[jseyfert3]

Well, it's time. Following up on my last post on a 2GR-FE water pump change, I now have successfully completed my 120,000 mile spark plug change on my 2014 LE. This may or may not be applicable to 2nd gen Siennas using the 2GR-FE engine. The spark plugs themselves should be, but the process of getting to them may be different, I don't know what a 2nd gen air inlet looks like.

General Process Overview & Possible Alternatives:
The front three spark plugs/coils are easily accessible from the front, at any point. The back three are where all the time goes. To get them out, per the FSM, you must remove the windshield wipers, wiper mechanism, wiper cowls, the complete air inlet assembly, and the air inlet manifold. Once you do, you have access to the rear plugs and coils pretty easily. This entire process took me about 6 hours of actual work time, not counting tool setup/prep, purchasing parts. I was taking pictures along the way, so I was slightly slower than I otherwise could have been. It's not too hard, but patience is required to not brake a bunch of clips and latches.

I've read about people who successfully changed the rear spark plugs without removing anything, by reaching around the back blind. Given the trouble I had working on a couple of bolts, I don't think I'd want to change these blind. But it may be an alternative you can explore to save some time, potentially.

Tools You Need:
Tools for this job were shockingly few. I used:

• 3/8" drive ratchet, with
  • 8 mm socket
  • 10 mm socket
  • 12 mm socket
  • 14 mm socket
  • 9-12" extention
  • 6" extention
  • 3" extention
• Pliers
• 5 mm hex wrench
  • I used an adapter with my ratchet
  • Needs to be fairly skinny for one of the bolts
• Two flat screwdrivers
  • One should be sufficient, if it's the right size
  • Used to pry covers and latches open
• A small allen key, or better a right angle pick
  • Used to pop a hard to reach wire harness latch
• Torque wrench
  • Should be capable of reading accurately in the 7-15 ft-lb range
• Breaker bar with 14 mm socket
  • Used on one of the top suspension mount nuts, which was a little sticky.
  • May not be needed, or may be needed on other bolts with different sized sockets.
• 16 mm spark plug socket
  • Not a regular socket, a spark plug socket has rubber or a magnet to hold the spark plug to install and remove it from the deep wells it resides in.
  • Bought a Performance Tool W38167 socket from Rockauto for $2.28. Not great, rubber kept pulling out of the socket, but it worked.

Here's everything I used. Oh, and I think I used a 12 mm combination wrench on one bolt, but I forget what or why, as I only used my ratchet putting things back together.

Parts You Need:
On the parts side of things, you obviously need spark plugs. Denso 3426 (FK20HR-11) are OEM, which I would recommend. Coils, well, some people say not to change them, but I've seen people report lifetimes of 150,000-230,000 miles on original coils. The best compromise seems to be change the three rear coils, keep as spares, and when a front coil dies, swap in one of the three you pulled from the rear, as the front coils can be changed in minutes with a single wrench, or even pliers in a pinch. I'd recommend this course of action. You do NOT want to repeat this in 25,000 miles because a coil died on the back. If you feel like spending another $150+, feel free to swap the front coils as well. Otherwise just throw one of the rear coils in your glovebox and keep the others in your spare parts box at home.

Other parts. I highly recommend you buy some vacuum hoses. I found mine had started to crack around where they push over the hose barbs on the majority of hoses, and one of these must be changed with the intake manifold off. One is much easier to change with everything off. Most of the rest is easily accessible later if you decide to skip. But get these on-hand before you start, as you can't buy from Rockauto and it'll take your dealer a few days to get them. I did not think about these hoses, and couldn't leave my van apart for 3 more days, so I get to go back and pull everything back apart in a week or three to change hoses. Joy! Save yourself the trouble and buy some hoses now.

Most people also recommend changing the PCV valve while you're at it. You can change this later if needed pretty easily, but but may as well change with the hoses and rest of the things.

All hose part numbers are Toyota PNs.

• Spark plugs, x6
  • Denso 3426 (FK20HR-11) are OEM, and what I used, and recommend. $12.50/each at Rockauto
• Coils, x3
  • Marginally optional, skip at your own risk
  • Denso coils are recommended.
  • I used Denso 6731309 from Rockauto at $54/each (OEM is like $125 MSRP)
  • Do NOT try to save a couple bucks going with cheaper coils!
• Intake Manifold Gasket, upper
  • Rockauto only had upper in sets with upper and lower gaskets. With a little more work, you can change the lower gasket, but I did not.
  • I used Fel-Pro MS96790 from Rockauto, at $35 for the set
• Throttle Body Gasket
  • Optional, if you remove the throttle body to clean (probably a good idea), you'll want one.
• Brake vacuum hose
  • 4477308040
  • Easier to change with everything off, but should be doable later without removing anything.
    • $75.39
• Evap hoses
  • 238260P130
    • $36.35
  • 238200P170
    • $32.84
• Vent hose no. 2
  • 122620P080
    • $41.77
  • MUST BE CHANGED WITH INTAKE MANIFOLD OFF, if you get no other hose get this one
• Hose assembly, vent
  • 122600P040
    • $24.77
• PCV Valve
  • 1220431120
    • $7.27

 

[jseyfert3]

May be a couple days. The laptop I was planning on using to sort the pictures decided to be glacially slow for some reason. So it may be a couple days till I’m back at my desktop and can sort the pictures out and get this how-to written.

 

[jseyfert3]

Couple other things. Wouldn't hurt to clean the throttle body while you're in here. I didn't, as I didn't plan ahead enough. If you do, get a new throttle body gasket, and some throttle body cleaner, and look up how to clean a throttle body.

Okay, it's get going. Got your tools, spark plugs, coils, and hoses, and get to work. We need to pull a bunch of this off.

My intake manifold gaskets, spark plugs, coils, spark plug socket, and headlamp.

Some homebrew to help the process along.

My FSM setup needed some work. But I couldn't find my 3-hole punch nor a binder. Ah well. I got the job done.

The first step I did was discharge fuel system pressure. This is NOT needed unless you want to remove the intake plenum under the intake manifold, to change that gasket or if you have a leaking head gasket you are also swapping. If you do, you touch the fuel lines, so you need to discharge fuel system pressure. To do this, pull this relay.

Then start the van, let it run until it dies, and start it again to make sure it didn't start. I needed 3-4 starts before it didn't run. Once done, disconnect the negative battery cable and put the relay back in and close the fuse box. All done here.

Next, we take off the windshield wipers. Before removing them, check your windshield for alignment dots. These are dots where the blackout paint in the lower section of the windshield, at one or both ends of the wiper blades, has been removed. If they do not exist on your windshield, use masking tape or similar to mark the position of the wiper blades before proceeding, so you have a reference when re-installing them to ensure they are at the correct location.

Use a screwdriver with some tape to pry the caps at the base of the windshield wiper arms off.

There's a nut under the cap. Remove this and the windshield wipers pull straight off. They are just splined shafts. I highly recommend you thread the nuts back onto the windshield wiper bolts, unless you like loosing things. I recommend unless it interferes with the next step, to immediately thread back in bolts/nuts removed once the piece in question is removed, as this in general is a great way to remember where they go, and not lose them. An alternative is a box with small compartments for the bolts/nuts from each step, and you notate which step they were used in, or just fill from left to right and empty from right to left or something like that.

Next pull off the covers on both sides of the windshield cover. These have like three different styles of clips. The one on the outside needs to push down as you slide it towards the inside of the van, I don't recall how the other clips worked. Just take it easy and you'll get it done. The strip going along the windshield is held with double sided tape from the factory. Mine also had some glue as the Safelite glass guy put some urithane glue on it as it wasn't holding down after he removed it. Not sure why he didn't just replace the tape.

Now the cowl itself. There is a guide pin in the center.

There's then a bunch of plastic latches that need to be removed. All but two were already broken (probably by the Safelite guy), and I broke the last two...here's a broken latch.

One the latches are free, or broken, lift off the center guide pin and pull forward, with a little wiggling at the rubber seals on each side of the engine bay, to remove. You also need to lift it above the windshield wiper connection points. This slides under the windshield (as well as being above it) so do not force it up or you'll break more things! Just slide it towards the front of the van, lifting just enough to clear the wiper joints when you reach them.

Once this is off, disconnect the wiper motor connector. This is a typical automotive electrical connector with a tab you press to release, then pull the connector free.

Once disconnected, there's three bolts with large washers holding the wiper mechanism down. Remove the bolts. Once removed, slide the mechanism to the right to clear the rubber bumper at the bottom that's in a slot, then pull it out.

Now it's time to remove the lower cowl (metal). First, on the passenger side, there's a big resistor or something. Disconnect this electrical connector.

It was starting to get dark, so I broke out the headlamp.

Meanwhile, the front three spark plugs and coils were just mocking me with how they can be removed without any of this other stuff removed...

Now disconnect the windshield heater element that sits under the wipers, and turns on when you turn on the rear window/mirror defrosters to keep ice from building up where the wipers sit.

The wiper/windshield heater wiring harness is still attached to the lower cowl.

Remove the harness from the cowling. These are pretty easy latches, they have a tab on two opposite sides, squeeze the tabs then lift the latch off the cowl. Hang the harness over the side of the van.

If I counted right, I've reached the 20 picture post limit, so more to come later (probably tomorrow).

 

[Therbi]

Wow, you are doing one seriously detailed write up. Nice work.
One thing I would add is checking wiper position before removing the arms. Most OEM glass has dots in the blackout paint to indicate where the wipers should be at rest but its always good to confirm before removing them. And if none exist, a bit of masking tape on the glass with a pencil mark so you know exactly where they go when you put them back on.

 

[jseyfert3]

Wow, you are doing one seriously detailed write up. Nice work.
One thing I would add is checking wiper position before removing the arms. Most OEM glass has dots in the blackout paint to indicate where the wipers should be at rest but its always good to confirm before removing them. And if none exist, a bit of masking tape on the glass with a pencil mark so you know exactly where they go when you put them back on.

Thank you. And that is a good idea.

 

[jseyfert3]

Remove the lower cowl assembly. There are two nuts on either end, I believe part of the upper strut mount, that need to be removed. And then there are 6 black bolts with washers along the sides/back that need to be removed. While not pictured, these bolts are easy to find. If you see a bolt on the upper part of the cowl, remove it.

Once all the nuts and bolts are removed, simply lift the cowl up over the studs on both ends and pull it forward, wiggling a litlle to get past the rubber at each side of the engine bay, and set the cowl aside. Your van should now look like this.

I recommend you take a moment and thread the bolts and nuts you just removed back where they belong, so you don't loose them/forget where they go.

Now, focus on the air intake at the front driver side of the engine bay. On the back of the air inlet are two vacuum lines. Remove the three latches on the hose clips to remove the clips from the air intake. One is where my finger is resting, one in the front of the picture, and one is below the image, just follow the lines down. The latches have two tabs you squeeze then lift the latch to remove, just like the wire harness on the lower cowl.

The air intake is held in place with two bolts at the front, remove these bolts.

Now pull the air intake towards you. On the back, you'll see two air joints separate.

Once they separate, with a little wiggling, pull the air intake up and out of the engine bay.

Now go to the back of the air filter assembly, on top. Disconnect the electrical connector from the mass air flow (MAF) sensor.

You have to disconnect the MAF sensor wiring harness too. This latch is pretty annoying, as it has a tab on both sides, and very little access. I was able to pop the passenger side tab by slipping a small allen key past the latch and then positioning it on the tab. Once in place, I pulled the allen key to press the tab and gently tilted the harness mount to bring that tab out of the hole and keep it there. While maintaining this gentle tilt, I used a screwdriver to press the latch on the driver side (opening of the latch mount), then pulled the harness mount out. A right angle pick would likely work better than a small allen key for this.

MAF harness unplugged and disconnected. You can see the tabs on the latch for the wire harness mount that you need to compress to get it out from the mount in this picture.

Now go over to the front of the air intake manifold. There's a small diameter vacuum line running to a hose barb on this. Simply pull this line off. (Center of image, just to the right of the little ball on a post that secures the plastic engine cover)

Back to the air filter assembly, remove this electrical connector on the vacuum control valve.

And remove the two wire harness mounts. One is a little two-wing latch that you should be pretty familiar with by now, the other is just a C-clip that secures the jacket of the wiring harness, just pull the harness out of this clip.

One minor tip to point out here. Note the white tape on the wire harness? That indicates the location that the harness attaches in the clip above the air intake valve in the above two pictures. Also take a look at the vacuum hoses, they have a paint mark on the sections they press into the C-clips. Handy for lining things back up when you re-install. Probably used on the assembly line for quickly positioning the harnesses and hoses.

Two more small vacuum hoses to disconnect. These are the bundled two you unlatched from the air inlet earlier. The larger of the two connects to the air filter box just to the left of the air filter access latch in this photo, to the right of the large rubber air bellows. Pull this off the filter box. The second one goes to the gray plastic tee just below the center of this photo. Pull this hose off the gray tee. If I'm motivated enough I'll replace this picture with a marked-up picture later. (Meant to do that on some of these photos, but got ahead of myself and uploaded them all before I remembered).

Here's where I wished someone had warned me about the vacuum hoses, as these small vacuum lines were cracking where they went over the hose barbs. This hose assembly with these two hoses (plus one more down where they terminate near the radiator under where the air intake was) are available as an assembly from Toyota for $116. I purchased bulk vacuum line from Bumper to Bumper auto parts for like $10 instead for all the small vacuum lines. Any auto parts store should have bulk small diameter vacuum line. I'll update with the ID of the small diameter vacuum hoses and how I changed them later, but as I didn't change them during my initial spark plug change we'll continue for now without changing these hoses.

Next, three small tasks to complete. Unclip the vacuum hose that's pressed into the rubber C-clip on top of the large rubber air inlet bellows. Remove the vacuum hose from the side of the bellows. This has a spring clip, which I initially tried to remove, but when I went to pull the hose off the plastic adapter just pulled out of the bellows, so that's probably easier to do here. Finally, loosen the bolt on the spring clamp on the throttle body side of the air bellows (the throttle body is the aluminum block the air bellows attaches to in the center-left of the image here).

This should be 18 images, so breaking here to leave room for two more images in case I forgot something and want to edit in another image or two later.

 

[jseyfert3]

Now remove the air filter assembly. There's only two bolts holding it down, both near the front of the box. One is pictured below, just behind the battery. A long extension and socket is what you need here. Be careful not to drop the bolt. A magnetic pickup to grab the bolt once it's loose would be useful here. The second bolt isn't pictured, but it's on the opposite side of the box, and easy to find.

Now pull the air inlet bellows off the throttle body, then grab the entire air filter assembly and pull it upwards to remove. The back of the assembly may seem to not want to come up. It's not bolted, just a post through a rubber bushing, so just pull and wiggle a bit to loosen if needed and it'll come up. Once loose, you'll have to maneuver and wiggle it a bit to get it to come out, it's a little tight but not too terrible.

With the air assembly out, you'll notice several small diameter vacuum hoses. If yours are like mine, some are probably cracking, so before you put this back in, I recommend you swap those hoses out, or at least inspect the ends of each hose for cracking to see if they should be replaced.

Your engine bay should now look like this. We are getting closer!

Getting even darker, so I added some extra light to supplement my headlamp. One of these days I'll have a nice garage to work on my vehicles in...

Next up is the throttle body cooling lines. Cooling being a bit of a misnomer here, as my understanding is the coolant is actually being used to heat the throttle body, to prevent the formation of ice in cool weather, high humidity driving. My cooling lines had white and black wrap on them, note which goes where, for me, the white wrap went to the driver's side hose barb.

Also we should note here that some people have mentioned that they do not remove the cooling lines, and just carefully maneuver the throttle body. I assume that means they remove the throttle body from the air inlet manifold, which I did not do. If you're going to remove the throttle body from the air inlet manifold to clean (which is probably a good idea) this is a route you can consider. Overall it's probably easier to just disconnect the throttle body cooling lines and remove with the manifold, then you can easily remove it from the manifold to clean it later, and not have it be in the way for the rest of the process and easier access for cleaning.

Finally the FSM said to drain the coolant at the start. If you also need to do a coolant change, feel free to do that prior to removing the lines. I thought "why would I do that? Not much coolant will come out" and I was right. So don't bother draining the coolant unless you need to do a coolant change.

Getting the lines off wasn't too terrible. Use a pliers to loosen the spring clamps and slide the clamps down the hoses a couple inches. Then twist the lines back and forth to help break them as you do that and alternate/combine with pulling. I was able to get them off this way. If they remain stuck, carefully using a screwdriver to push the ends of the hose off the barb can help loosen stuck hoses like this.

Once the hoses are off, keep them pointing up to minimize coolant loss. If you let them drop, you'll loose some coolant, maybe a lot, but almost none if you leave them up.

I tucked the hoses under the wire harness located right here to keep them out of the way and upright. It would be good to put some tape over the ends of the hoses to keep junk from falling into the cooling system lines.

This image shows how much coolant I lost. Not a lot, perhaps a couple oz at most.

On the back of the air inlet manifold, there's another vacuum line. Use pliers to loosen and move the spring clamp back a few inches, then pull the line off. Should come off easily, unlike the coolant lines (coolant lines always seem to stick really good).

Again, this hose was cracking. Except for one or two, all the vacuum hoses I removed were cracking. This is why I said to order those 5 vacuum hoses before you got started. Interestingly, the water hoses were fine, which was the case for the water hoses I removed earlier this year when I did my water pump. Either a better rubber, or the vacuum lines get exposed to gas fumes or something and degrade faster.

Anyhow, this vacuum line is connected to the brake system, which means it's what provides your power braking! So replace it if it's cracked, you don't want to loose your power brakes!

Remove the insulated vacuum hose from the front of the air intake manifold to the left of the throttle body in this picture, at the top. Squeeze the spring clamp and pull the hose off. Ignore the electrical connector hanging there, that's the windshield defroster power wire. Of note is the other end of this hose connects to the PCV valve, so you know where to find that valve if you are removing it.

A bit hard to see but a few small cracks in this hose too.

Now you need to remove the electrical connector and wire harness latch from the throttle body.

The wire harness latch is annoying. It's the first latch we've seen of this style (but not the last), and it's positioned so you can't see what you're doing. Look at the following picture of it removed before removing it to see how it works. The side facing the camera in the picture is normally facing to the back of the van (you can see the bracket this latch slides onto above and behind the latch). The little tab there must be lifted up with a small screwdriver to release it, and while holding the tab up, slide the latch toward the back of the van to release and remove it. Once the latch starts sliding, you can release the tab.

If you want to practice before doing it blind, this same style of latch is used to hold the wire harness for the front bank of spark plugs and coils. Borrowing a picture from later, you can see two of these latches on the top side of the wiring harness here. These do not need to be removed, but they are right in front of you and easy to practice on to get a feel of how the latch works.

One more vacuum line to remove from the air inlet manifold. This is the evap system vacuum line, which if I'm correct is what is pulling gas fumes out of the charcoal vapor canister in the back of the van.

Like the other lines, this one was cracked, but even more than the other lines. This, plus the hose it connects to on the other side of the vacuum valve seen in the prior picture, are two hoses of the 5 I told you to buy.

And another 18 pictures down, to be continued...

 

[jseyfert3]

Next, remove the inlet air control valve electrical connector.

And now we get to the curses. Behind the manifold and inlet air control valve, there's a bracket that secures the inlet manifold. It's a 12 mm hex head, and you may want a short extension on your ratchet (can't remember if it's required, but I used one).

You have to get this bolt out blind, so here's where the bolt is located when my ratchet was on it. Just feel back there with your hand to locate the bracket and the bolt.

If you're like me, you're probably cursing some unknown design engineer right about now, but we're unfortunately not done. There's a second bolt below the throttle body that needs to come out. This also requires a 12 mm socket, and I did not use an extension for this one.

Once those two bolts are out, we can remove the inlet air manifold itself! First remove the two nuts on either end of the manifold. You can see the stud on the left of the manifold clearly here (not the bolt my ratchet is on), and just barely peaking out the right side of the manifold. Once the two nuts are removed, remove the four bolts with a 5 mm allen wrench on a rachet, or T-handle allen, or anything long and skinny.

My initial choice of a 3/8" drive, 5 mm allen adapter worked for 3 of the 4 bolts, but was too wide for the last one. I got it out with a 5 mm hex bit and hex bit to 3/8" drive adapter. A 1/4" drive, 5 mm allen adapter and 1/4" extender is probably best here, if you have that (I mostly only have 3/8" and 1/2" sockets and drivers).

Once these two nuts and 4 bolts are removed from the top of the manifold, the manifold itself will lift straight up off the studs and then is free to remove.

Here's where I make an exception to my normal policy of putting nuts and bolts back where I got them. I would not recommend putting those 4 bolts and 2 nuts back on the air intake plenum where they bolted down the manifold, as you do not want to risk fumbling them and dropping them down the air intake!

My air intake was really dirty around the intake plenum openings, as shown below. I took a rag and very carefully wiped off this junk, taking great care to not push it down the air intake openings! I then took a clean rag and placed it over the air intake openings, to avoid dirt and the possibility of dropping things down the air intakes. Cover these openings with something! (Clean off the dirt first) A rag, or masking tape, or something of that sort. You do NOT want to drop something down these or you'll be cursing yourself as you tear the engine apart to recover it...

However, at this point we have access to the rear plugs and coils! Congratulations, go take a break, have a beer or something. I watched Spider-Man: Into the Spider-Verse with my girlfriend and then went to bed myself (okay, actually I fiddled for a bit longer before doing that, but this is a great point to take a break).

Just a couple more things before we can get the rear plugs out. First, the bracket holding that annoying bolt to the inlet manifold must be removed. This is another bolt with a 12 mm hex head.

Next, the rear ignition wire harness gets in the way of things, so you need to lift off several of the latches. Here's a picture showing my screwdriver prying up the latch tab before I slide the latch up and off the bracket.

Only at 12 pictures, but need to go get some work done. More to come later today!

 

[jseyfert3]

Lunch time, let's see if I can crank out a few more pictures.

Before we can remove the coils, we need to remove the stupid connectors on the spark plug coils. The locking tabs break very easily. Firstly, pressing the portion of the tab that is supposed to release the lock doesn't work, and on one of my coil connectors just pressing that snapped off the lock tab!

Next I tried using a screwdriver to pry up the locking portion of the tab (closest to the coil) while pulling the connector, and snapped off more tabs. I started on the front, and by the time I got to the back, I only snapped off 1 of the tabs. But I lost 4 in total. I hear everybody breaks at least some of these, just a bad design or bad material choice.

I should add I've heard of some people not removing the coil connectors, and just carefully pulling the coil while plugged in, but if you change the three rear coils, you do need to remove the connectors. You could try leaving the front coil connectors attached though, if you aren't changing the front coils.

There's an electrical connector alongside the passenger side front coil that is useful to unplug. This is a standard connector and unplugged easily for me with no issues.

Now time for the coils and plugs. I worked one spark plug at a time. I'd pull a coil, pull the plug, put a new plug in, torque it, insert the new coil (rear) or coil I pulled (front), tighten it down and connect it before moving to the next plug, to easily keep track of which ones I had already finished.

First coil I removed, starting on the front with easy access for practice.

Now pop your spark plug socket on a extension and pull the spark plug. Once it's fully loose, it should pull right out as the spark plug socket grabs it. If your spark plug socket has a rubber coil like mine, you'll need to (gently but firmly) push straight down to get it to seat. On my first attempt I didn't push, and it didn't grab the hex on the spark plug, because the socket was sitting up so high as the rubber wasn't pushed over the spark plug.

Mine all came out easily, but I've heard some people talk about stuck plugs, and possibly damaged threads from trying to rip them out. So if a plug seems to require excessive force, perhaps stop and read about how to deal with it before you break out the breaker bar.

Old plug vs new plug picture, don't need to tell you which is which. But like most here have observed, these old plugs are in good shape for 120,000 miles. My motorcycle plugs were so, so much worse at like 15,000-20,000 miles...

I did multiple times have the rubber insert in my cheap socket pull out when I pulled the old spark plug out of the socket after removing it from the engine. I just pulled it off and stuck it back into the socket and used a tool to press it into place in the socket fully. I was worried this would happen after I installed a new spark plug and the rubber would be stuck down there, but it only happened once. When it did, I stuck the socket back down the spark plug hole, pressed it over the spark plug, and pulled it off, and it came back up with the socket. May be a better quality spark plug socket is in order, or at least use some super glue to glue the rubber to the socket.

Now grab your new spark plug and press it into the spark plug socket fully. I did this with the plastic protector on the spark plug threads, then removed the protector once it was seated in the spark plug socket. Don't press on the electrode at the top of the spark plug to seat it into the socket!

I did not use anti-seize on the plugs. It seems the general recommendation is not to on modern plugs, but some swear by it. If you do, read up how lubricating fasteners changes the torque values and adjust appropriately.

Now, on a long, straight extension (I recommend not a flex drive), insert the spark plug into the hole. With the extension centered in the hole, carefully and by hand thread the spark plug into the engine block. DO NOT FORCE, if it doesn't turn something is wrong or it's cross-threaded, and you do NOT want to cross thread your spark plug holes! Once it's going, keep spinning it in by hand until it touches.

Now use a torque wrench to tighten the spark plugs. Toyota spec is 13 ft-lbs. If using a click-style torque wrench, do not use your 200 ft-lb 1/2" drive torque wrench, it will NOT be accurate down this low. I think on click-style torque wrenches the accuracy spec is for the upper 80% only, the bottom 20% is no good (so anything under 40 ft-lbs on a 200 ft/lb torque wrench). Get yourself a torque wrench with a usable scale. For click style torque wrenches, this is usually a 1/4" drive wrench, probably marked in in-lbs, around the range of 40-200 in-lbs. 12 inches in a foot, so divide those by 12 to get ft-lbs, and that is 3.3-16.6 ft-lbs.

As far as I am aware, beam style torque wrenches don't suffer an accuracy loss at low torques, as they are measuring how much the beam bends from the torque, which is very accurately determined with a simple engineering equation (for us mechanical engineers, this is probably in our textbooks). So I used my 3/8" drive Crafsman beam style torque wrench. Works really well, so long as you have enough room to swing it.

Regardless of which type of torque wrench you use, remember that tightening torque values are only valid if the fastener is moving. So continue to slowly but surely continue tightening until the scale says the torque (beam style) or it clicks (click style), then stop. If you need to stop to adjust, that's fine, just try to leave enough swinging room as it tightens that you aren't at 11 ft lbs when you stop. If you are, the wrench could possibly indicate 13 ft-lbs when you start, without the fastener moving. If you stop short of the click, and then it clicks immediately when you apply pressure again without moving, general procedure as I understand is to back the fastener off a bit (like 1/8 turn), then tighten again. It should start moving without clicking and then keep it going until it clicks. However, I'm not sure this is appropriate for spark plugs or not. I'd recommend you start snugging it with a torque wrench, mine threaded in a bit more than I could do by hand on the extension when I started with the wrench before the torque started building up. Once it starts building up, stop and adjust the wrench to leave as much swinging room as you can so you can get that click/indicator with a nice continuous tightening action.

Nerd alert: This happens because the coefficient of static friction is always equal to, and generally larger or significantly larger than the coefficient of kinetic friction.

Note: Denso does list hand tight plus x fraction of a turn for their spark plugs, if you can't use a torque wrench, but Toyota does not list this as an alternative and Denso says you should only use it if you cannot use a torque wrench, and to use a torque wrench if you can.

Once torqued, put the coil back in (new or original, depending on front or back).

I made sure to wipe off my old coils, and this let me easily see which ones I had done.

The rubber seals were dirty, so for the front coils I reused, I made sure to wipe them off.

The rear plugs are not hard, but at least one, I had to hold the socket with spark plug over the hole and attach the extension before lowering it in. For removing, I'd have to remove the ratchet once loose, pull the extension out, then disconnect the extension while holding the socket with spark plug to get enough room to remove it. Carefully move the wiring harness as needed to remove/install coils and plugs. Watch the connector on the very left of this image (red and green wires), there's not a lot of room and too much force on the harness could damage these very tiny wires. I wanted to unplug that, but unlike the rest of the standard automotive connectors (coil connectors not included) this one didn't unplug easily, though I tried on three separate occasions. So unplug if you can, otherwise just be careful.

I thought I'd need a click-style small torque wrench (I don't have one, only a large 1/2" one), but it turns out there was plenty of room to use my beam scale torque wrench on the rear plugs.

Comparison between the Denso coils I bought and OEM ones, which I was kinda surprised to see did not have a Denso stamp on them alongside the Toyota stamp.

Now we'll deal with the broken coil clips. I looked on here and most people seemed to recommend zip ties. Some appeared to have bought new connectors, but left no details as to if they spliced wires, or bought a new shell, depinned the old connector, and put the existing pins/wires into the new shell, etc. I used zip ties. I put one around the coil to hold it in, with another around the plug to hopefully keep it from sliding down off the connector.

Detail of where I put the other zip tie. Make sure it doesn't sit on the wires and ruin them.

 

[jseyfert3]

I will not give detailed instructions on putting things back together. It's essentially the reverse of taking it apart, with a couple extra steps I'll point out along the way. Before we talk about putting it back together though, I'd like to mention that as I didn't have the hoses, I won't talk about replacing them or the PCV valve. I also won't talk about cleaning the throttle body and MAF sensor as I haven't done that yet. I'll add an addendum to this thread when I have more details after I swap hoses and clean things.

First step on putting things back together is to replace that intake manifold bracket on the rear cylinder block. I left it just short of being tight so I could move it to line up with the intake manifold. I wonder if attaching it to the intake manifold first is possible, as it may be a lot easier to insert the lower bolt than it is the upper bolt.

Also the leftmost (most passenger side) of the ignition wire harness latches behind the intake air manifold should be left disconnected, for now. You'll thank me shortly. Be sure to connect the rest of the ignition wiring harness latches though.

If you want/need to change the vacuum hose that is under the intake air manifold, do that now!

Once done, because I planned to go back in and replace the vacuum hose under the inlet manifold (not pictured) in the next few weeks, I did not change my inlet manifold gaskets. But you should. Remove the old ones, make sure the grooves are clean, make sure dirt didn't fall into the inlet channels, and put in new gaskets.

Here's my original gaskets.

Interestingly, one had a tear. If this were not temporary, again I would have been replacing the gaskets, and I will soon. I'm curious how it got a tear, and there was not orange stuck to the inlet plenum that I saw. Perhaps someone removed it earlier? That seems odd, because all prior service was done at a Toyota dealer, the same dealer, for all 106,000 miles, so if someone did go in there the Toyota FSM says to use a new gasket, and they should have. Odd.

Remove the rag/tape over the inlet plenum, make sure the surface is clean, and drop the inlet manifold down over the two studs. Install and lightly tighten the four bolts on the intake manifold. Install and lightly tighten the two nuts on the intake manifold. Then, use your torque wrench to tighten things in the following order (bolts to 13 ft-lbs, nuts to 12 ft-lbs):

1. Front passenger side bolt
2. Rear passenger side bolt
3. Rear driver side bolt
4. Front driver side bolt
5. Passenger side nut
6. Driver side nut

Now the *** bolt behind the IAC valve. Pictured (barely) is the connector on the wiring harness that should not be connected yet. I did, and then had to reach back there and disconnect it so I could move the wiring harness to put the bolt into the intake manifold. You have to do this all blind, with a bracket that you need to line up, wiring harness in the way of the bolt hole, reaching around the back, cursing and trying to not drop the bolt. I only dropped it once or twice and it only took me 15 minutes or so (felt like 45 minutes). This is where I wonder if attaching the bracket to the manifold before installing the manifold is easier, and will update later when I do this again to change that hose if it is possible and if it is easier.

Latch the wiring harness connector down once the bolt is in and tightened, and don't forget to tighten the bottom bolt. And install the bolt under the throttle body too (the second one you had to remove from the back, blind). May be easier to install this bolt if you leave one of the other two bolts on the other side loose until you install this one and get it threaded. Connect up the wires and vacuum hoses you disconnected from the manifold.

If changing vacuum hoses, this is where you should stop and do the rest of the vacuum hose swaps and PCV valve change.

Install the air filter assembly. On the right backmost part of the assembly as pictured below, you can see a black stud protruding from the black leg. This needs to be lined up with and inserted into the white rubber bushing you can see just above it, down inside the engine bay. You'll need to do some wiggling and try a few positions to get this back into position, but it's a piece of cake compared to those two bolts, right?

Everything else is really a straightforward piece of cake from here. Just reverse what you did previously, it all goes back together nicely.

Once I got to the part where I was going to install the lower metal windshield wiper cowl, I just rested it instead of bolting it into place so I could test run the engine before finishing. Not like it makes a huge difference at this point, but still, it's something, in case something doesn't work.

Before starting the engine, remember that resistor you unplugged under the cowl? Plug that back in! I found on here that if you forget that, the van will start and then die in about two seconds.

I started the van up, and it ran just fine! Horray! You did it! Pat yourself on the back! Record the mileage for your service records. FYI if you've signed up for a Toyota Owner's account, and entered your vehicle VIN, not only can you see all previous dealer service, but you can enter DIY and 3rd party service records, for your reference, and presumably Toyota dealers can see this as well, and maybe future car purchasers? In any case, if not, it's at least a handy place to keep a record of your DIY service IMO.

I then finished up the install. For some reason I disconnect that resistor, don't know why, maybe I needed the room, or thought I did, to move the cowl to install it? Don't unplug unless you need to, and plug it back in if you do, once the lower cowl is installed.

Also when installing the windshield wiper mechanism, don't forget to plug that back in either.

When installing the windshield wiper blades, there should be three dots near the passenger side tip of the driver side wiper blade on the windshield, the blade lines up below but close to the upper dot (and one dot on the driver side of the driver blade on the windshield, which is easier to use). On the passenger side wiper blade, there should be two dots on the passenger side of the blade. Again it installs just below the upper dot. If they are above or below (seemed you could move them in about 1" increments), pull the wiper off the spline, rotate, and install again to change position. If you don't have dots on your windshield, line it up with that tape you put there, or if you forgot that, reference my picture below for approximate location.

YOU ARE ALL DONE! Fire it up, if you haven't already. If it starts and dies after a second or two, you probably forgot to plug that resistor below the wiper cowl in. I did, after I initially plugged it in for the earlier engine test but unplugged it afterwards, and started my van 6 times thinking because I discharged the fuel pressure it needed to get fuel back, not thinking about how I didn't disconnect any fuel lines so the pressure would be back instantly when the pump turned on as no air needed to bleed out. I finally remembered seeing that in passing on the forum that it would start but immediately die if that resistor wasn't plugged in, and did that.

And later when I started driving, I hit my windshield wipers and they didn't work. I turned back around, and in the light rain had to remove the wipers and upper cowl and plug the wipers back in. Oops. Got carried away by how easy it was and forgot to carefully check each step for missing actions. At least it was that and not the throttle body connector I forgot to plug in...

And just for fun, to push in the be prepared with hoses, here's three more hoses that I didn't previously picture that need replacing.

Good luck! Let me know if you have any questions, comments, or things I forgot. I'll post a mini addendum here once I tear it back apart to replace vacuum hoses, outlining that, plus outlining throttle body and MAF sensor cleaning.

 

[jareza]

Dude, we are not worthy of you!
you are the real hero!
I sold my GEN3 van, but this needs to be stickied!

 

[copydoc]

Now I see why it costs so much to “change a few spark plugs.” I guess the engineers had their reasoning.

 

[supra129]

Nice write up and I'm sure it will help out a lot of members on this forum. This is very similar to the second gen Sienna with the 2GR-FE engine. The only difference is the air filter box design, you don't need to remove the whole box just the lid on the second gen. The wiper cowl is not held on by the top strut bolts. Just about everyone breaks those coil connectors but they can be replaced, no need to splice the wires just de-pin them and insert them into the new connectors. Magnetic spark plug socket is a must, it's annoying to deal with the rubber insert coming off especially if it gets stuck in the spark plug hole.

4 Packs Ignition Coil Female Connector Plug Harness Pigtail Compatible with Chevrolet Toyota Lexus Pontiac Scion Ignition Coil Connector Harness L4 2.4L

Buy 4 Packs Ignition Coil Female Connector Plug Harness Pigtail Compatible with Chevrolet Toyota Lexus Pontiac Scion Ignition Coil Connector Harness L4 2.4L at Amazon. Customer reviews and photos may be available to help you make the right purchase decision!

www.amazon.com

 

[eiko]

Thank you. Absolutely invaluable. You could sell this info.

 

[Vanna13]

THANK YOU! I just did this last week on my 2013 XLE with 164k that threw P0300 and P0301 codes on a cold start up and used this as a guide. Having the part #’s all organized by you was invaluable. I also broke the first clip and repinned with a new plug as supra129 suggested. I was able to get the plenum off and plugs/coils changed without removing the cowl as some others have described. Overall a decent size job and satisfying to have completed. Van is running like new again!

 

[sbihue]

Lunch time, let's see if I can crank out a few more pictures.

Before we can remove the coils, we need to remove the stupid connectors on the spark plug coils. The locking tabs break very easily. Firstly, pressing the portion of the tab that is supposed to release the lock doesn't work, and on one of my coil connectors just pressing that snapped off the lock tab!

Next I tried using a screwdriver to pry up the locking portion of the tab (closest to the coil) while pulling the connector, and snapped off more tabs. I started on the front, and by the time I got to the back, I only snapped off 1 of the tabs. But I lost 4 in total. I hear everybody breaks at least some of these, just a bad design or bad material choice.

I should add I've heard of some people not removing the coil connectors, and just carefully pulling the coil while plugged in, but if you change the three rear coils, you do need to remove the connectors. You could try leaving the front coil connectors attached though, if you aren't changing the front coils.

There's an electrical connector alongside the passenger side front coil that is useful to unplug. This is a standard connector and unplugged easily for me with no issues.

Now time for the coils and plugs. I worked one spark plug at a time. I'd pull a coil, pull the plug, put a new plug in, torque it, insert the new coil (rear) or coil I pulled (front), tighten it down and connect it before moving to the next plug, to easily keep track of which ones I had already finished.


Now we'll deal with the broken coil clips. I looked on here and most people seemed to recommend zip ties. Some appeared to have bought new connectors, but left no details as to if they spliced wires, or bought a new shell, depinned the old connector, and put the existing pins/wires into the new shell, etc. I used zip ties. I put one around the coil to hold it in, with another around the plug to hopefully keep it from sliding down off the connector.

Detail of where I put the other zip tie. Make sure it doesn't sit on the wires and ruin them.

Well, you are past this but personally, if I am doing all that work, I would have replaced the connector housing by de-pinning the existing ones or just breaking them up since they would be discarded. Here is a set that I have in prep for when I have to do this job. Coil Connector Housing using this..Depinning Tool set

Being constantly exposed to engine heat, the plastic does become brittle over time and will fall apart. The trick to removing these is to first push the connector towards the coil which will relieve pressure on the tab and then use a pick to go inside the tab and lift it.


An excellent, comprehensive writeup