Failing Water Pump - Now a How-To Guide for 2GR-FE engines (V6, used from 2007-2016)

q0987 said:

Hello jseyfert3,

Does Aisin WPT803 come with o-rings?

Thanks

Click to expand...

It comes with a new gasket that goes between the water pump and the engine block. This is the only gasket that is part of the water pump itself.

However, to get access to the water pump to remove you have to remove the thermostat and thermostat housing, breaking three gasket/o-ring sealed joints. These three should be replaced. I listed the Toyota part numbers you can use to search for these, plus the non-OEM ones I actually got from Rockauto. On a place like Rockauto or other car parts site you can use the Toyota PNs to find non-OEM ones. That’s how I found the three O-rings on Rockauto, by searching the Toyota PNs and choosing an oring that popped up with that PN search, as the parts have OEM numbers that they replace. Not all of them actually showed up on Rockauto under my vehicle, but all showed up with a Toyota PN search.

I got the Toyota PNs by looking at diagrams on parts.Toyota.com

I should also note the part numbers I reference are for the V6 engine in my 2014, but parts.Toyota.com listed two different engines. It appears this was sold through 2012 with an option for an I4, and if that’s the engine you have these PNs won’t work.

@q0987 quick update. I got my Aisin pump and it actually had two of the three o-rings/gaskets I said you needed to buy separately. The only one it doesn’t have is the thermostat O-ring. Probably tomorrow I’ll post more details, pictures, and update my post with the part numbers to indicate this.

Another general update: I removed the tensioner pulley from below the van. I also confirmed you can relatively easily remove and install the idler pulley from below as well. So there’s no need to worry about changing the tensioner/idler pulleys or pulley bearings when you do a water pump swap if they still look good and spin smoothly, cause you do NOT have to tear everything apart to remove these pulleys, you can simply remove the front tire and then remove the pulleys through the wheelwell after you remove the belt.

I also got a good look at the tensioner this way and there’s no way the tension itself could be removed without removing the AC compressor. So for the people that said they replaced the tensioner, I have no idea how you managed to do that without pulling the compressor, unless you had a different engine than the one I have.

More details and pictures of all of this will be posted soon, probably tomorrow evening. I expect my van will be drivable tomorrow, as I’ve successfully removed the old water pump so I’m officially halfway through this job. Haven’t been working on it a lot, been busy with work and other things so mostly just been doing 10-45 minute chunks mainly. I’d agree with estimates I saw here that you could do it in 4-8 hours if you had the parts all lined up and had reviewed the information on how to change the pump. I suspect if I did this again it would take about 3-4 hours if I had all the parts and did it all in one go.

Okay, so I'm going to turn this thread into a how-to. This will likely be a multi-part post, over the next day or two. Hopefully this is helpful for the next person and saves them time looking up a lot of information. This how-to is for the 2GR-FE engine, which is the 3.5L V6 uses from model year 2007-2016, but some of the steps may slightly differ for the 2nd gen vans, as they may have different space limitations or engine mounts, even if they use the same engine.

So, is it hard? Not really. If you've done other minor repairs before, you're probably good to go here. It's more frustrating than anything, due to the tight quarters. Timewise I've seen estimates from 4-10 hours for DIY jobs. I took maybe 8-10. Hard to tell exactly, cause I was busy and did a lot of small sessions before and after work, before cranking out the majority of this this weekend. I got the new water pump in last night with most of the bolts finger tight, so today was starting at just after the halfway point. Took 4 hours of work, including breakfast. So 8 hours total seems like a pretty reasonable estimate for my time.

Parts you need:

• Water pump - The Toyota OEM part is 1610009442. I went with the Aisin WPT803, bought from Rockauto. The OEM pump is also made by Aisin. In theory, these are identical pumps, but in practice they may be different. Aisin offers a 12 month/12,000 mile parts warranty. Toyota offers a 12 month parts-only warranty. So in either case, you're good if the pump fails, but in neither case will labor be paid out for a replacement.
  • Both of these come with the pump gasket, the thermostat housing gasket, and the water outlet pipe o-ring. It appears most if not all the pumps on Rockauto come with these three seals, but verify they do. If you see two different sizes of o-ring in the pump picture, then they should.
  • If the pump you choose does not come with these other two gaskets/o-rings, then you need Toyota PN 163250P020 and 9676124021 or equivalent.
• Thermostat gasket - Toyota OEM part is 1632562010. I used a Fel-Pro 35445 from Rockauto, mainly because they were one of the brands that could ship from the same warehouse as my pump the same day.
• Thermostat - Toyota OEM part number 90916A3002. I used an Aisin THT019 from Rockauto.
  • Technically, you don't need a new thermostat. But the Aisin one was $15, and since I was removing it, and I've had to replace thermostats on other vehicles before 200k miles, I figured may as well change it.
• Coolant: 2-3 gallons Toyota super long life pre-diluted coolant, or compatible equivalent. Compatible is the key word, as mixing incompatible coolants can lead to bad things.
  • Like transmission fluid, I prefer to use the manufacture's fluid for this. Doing research, the Toyota stuff is really good. All the aluminum cooling channels were in pristine shape on the inside, so this stuff works well. I spend $23/gallon at my local dealer.
  • Capacity of the system in total is just a tad under 3 gallons, so get three if you want to be safe or you plan to remove the engine drain cocks for a more complete coolant flush while you're at it. I'm pretty sure my coolant was flushed ~13k miles ago, so I wasn't worried about locating the engine block drain cocks to do a complete drain. Though doing so would likely make it slightly less messy when you pull the pump. More details on that in the picture section.

Note: Technically speaking, you don't need to remove the thermostat. You just need to remove the thermostat housing. However, I tried installing the housing with the coolant pipe you remove to get at the thermostat installed, and couldn't easily put it back in like that. But the service manual doesn't specify to remove this pipe or the thermostat, so technically it's possible...

Parts you may want to replace:

• Radiator hoses - A lot of people change the radiator hoses at this time. I skipped this, my hoses looked in good shape. But since you have to drain your coolant, it's not a bad idea.
• Idler and tensioner pulleys - You have to remove these to get the pump out, so a number of people change these at the same time. They aren't terribly expensive, but the tensioner pulley isn't sold by Toyota as a replacement part. Only the tensioner itself (including a new pulley). Other people buy replacement bearings and press out the old bearings and press in new bearings.
  • I skipped doing either pulley or bearing replacement after I realized both of these pulleys can be removed from the passenger front wheel-well. You only need to jack the front of the van up, remove the passenger tire, remove the plastic shield between the tire and engine, and remove the belt and you can remove both of these pulleys without doing anything else. I think a lot of people thought they had to go through the long and tedious process required to gain access to the water pump to remove these pulleys. It's not hard to get them out later through the wheelwell, so as long as they spin smoothly I'd personally say just leave them.
• The sky's the limit. Some people have replaced alternators and even AC compressors as PM during a water pump swap. I thought that was going just a tad too far. But certainly, if you remove your belt and your alternator isn't turning smoothly, or your AC compressor isn't working, now's the time to replace them.
• Tensioner - A lot of people mentioned replacing the tensioner itself at this point, also as a PM. But on the 2GR-FE engine, the mounting bolts for the tensioner are behind the compressor. You can't remove the tensioner without removing the compressor. And removing the compressor is it's own can of worms.

Tools you need:

• 10, 12, 14 mm sockets.
  • I also used a 14 mm deep socket, but I can't remember why
• 10, 12, and 14 mm combination wrenches
  • 12 point wrenches are highly preferable for some of the bolts
• Ratchet + various length extensions
  • 3/8" drive is what I had.
  • 1/4" drive ratchet and sockets would have made several of these bolts easier to get off.
  • 1/2" drive would be too big.
• Security lug key + 19 mm socket key
  • Or the other size that fits this key, or a regular deep socket if you don't have security lug nuts
• Pliers
• Breaker bar or similar for lug nuts.
• Jack & jack stands

Tools that are useful, but may not strictly be required:

• Various flat screwdrivers for all the tasks flat screwdrivers are used for that doesn't involve driving screws (prying/pounding/etc)
• A hammer, to help persuade sticky parts with the afformentioned flat screwdriver
• A wire brush for cleaning off bolt threads
• 5 mm hex key, or similar, to hold the tensioner pulley open for easy drive belt removal/install
• Locking pliers, the poor man's special service tool (SST) substitute for SST 0996010010
  • Looked up just now, this is apparently $350-450! But it appears there are similar tools starting at $30
  • It may also be possible to crack these bolts free before removing the drive belt, thereby avoiding any sort of tool to hold the pulley. But I didn't check, and the belt may not hold it securely enough to keep it from spinning while you crank on the bolts.
• Torque wrench, if you want to torque the water pump to specified torque
  • I also use a torque wrench on my lug nuts. Don't want my wheels coming off, but also want to be able to get the lugs off on the side of the road if I need, so I always use a torque wrench on my lug nuts.
• Anti-seize: All the bolts came out pretty easy as far as car work goes, but I did use some for the engine mount bolts as well as all the screws that went through sheet metal and so had gotten very rusty.
• Funnel, for filling coolant.
• Fast Orange, for cleaning your hands
  • I used to use Goop, but Fast Orange works so much better. If you work on your car, just get the gallon jug with the pump and keep it in your garage. Cleans off the stickiest grease and wipes clean with shop/paper towels, unlikely the oily residue Goop left
• Shop towels/rags
• Headlamp
  • Working on vehicles, a headlamp is just the best thing you can have for light. Get one with a floody (wide) beam, don't get one with one of the tightly focused beams. Those are good for walking at night, but you want a really wide throw for close-up mechanical work.

Here's everything I used for this job. The only thing not shown in the picture is the thermostat and thermostat gasket. P.S. Don't stick your new water pump on a rough surface like this, you could scratch the sealing surface. The one pictured is the old pump, so I didn't care.


More coming tomorrow, stay tuned.

q0987 said:

Q1 > How many engine mounts on the bottom of the car did you loosen?

Q2> When you jack the engine up through the oil pan, did you notice any deform of the oil pan after you finish the job? I am curious how much weight the oil pan can support?

Thank you!

Click to expand...

None, because I did not jack up the engine. The FSM says to jack the engine up so the lower, longest bolt of the passenger top engine mount bracket clears the AC lines. Then you are supposed to lower the engine again until you're done and jack it back up so you can get this bolt back in. I was able to get the bolt out and in simply by loosening the bracket holding the AC lines and gently pushing them back towards the side of the engine bay, and wiggling the bolt/bracket combo out.

I only used the jack to raise the entire front of the car off the ground so the wheels weren't touching, then set it down on the pair of jack stands, so that I could pull off the front passenger tire and access the belt and some of the screws from below. It's probably not strictly necessary for this job, but without it it would be a lot harder to reach a couple of the bolts on the water pump and get the belt back on.

The jack in the front center was mainly because I've never liked how if you jack at a corner, the jackstand can't go where you jack, so you're either jacking where you aren't supposed to, or placing the jack where you aren't supposed to. The exception for this is the clever, but expensive jack I once saw that had a slot cut into it so the jackstand could fit in where you jacked the vehicle up, which avoids this issue.

When I had the Toyota TIS subscription I downloaded the page that showed the proper jacking locations, which are essentially the same as what is listed on tsienna.net, though that is for the 2nd gen. The front center jacking location is on the front crossbeam. Look under the van, at the back edge of the plastic splash guard. There's a semi-circle cutout on this back edge in the center. Behind this cutout is the crossbar, with a slightly lowered "hump". This "hump" is where you position a jack to raise the front end of the vehicle. Then place the jack stands at the side frame edge behind the tires, between the notches. Also note the precautions for jacking a vehicle front and/or rear end, the precautions listed are the same on tsienna.net as they are in the 3rd gen FSM. For how to chock the tires before jacking, and to release the parking brake and shift to N before jacking. I did this, but put the parking brake back on after I jacked the front end up and placed it on the jackstands and before working under the van. Then I released the parking brake after checking the chocks before jacking the front end back off the jackstands and lowering it back to the ground.

I didn't do it this time, but another trick I learned somewhere was as a backup to the jackstands, if you remove a tire, place the tire on the ground just behind the jack stand. That way, should the jackstand fail or slip for some reason, there's something else solid below the frame to hopefully catch the vehicle before you end up catching it... I've also used the jack itself as a backup to the jackstands, but this isn't as solid as a tire, but still better than nothing. If I use a jack as a backup to a jackstand, I apply the full weight to the jackstand, then position the jack under a suitable place, keeping it just off from touching the vehicle so it's not taking any load, and ensure the valve is shut completely. But do not, I repeat DO NOT work under a vehicle for any reason that is supported by a jack, only ever work under a vehicle supported by jackstands, after lowering the weight off the jack and onto the jackstands, and verifying it's securely supported.

Okay, lets start this off. I've got some 60 pictures

I'd probably start by finding a level surface you can work on the vehicle, and jack it up. I used the front center jack point, as outlined in the above post, and placed jackstands in the two front jacking points, leaving the front tires just off the ground when lowered onto the jackstands. Remove the front passenger tire, and the plastic divider between it and the engine. This plastic divider has two screws and a plastic clip, the latter of which was jammed and broke on me. I need a new one but don't have the PN for it yet. Once you get this off, you have access to the drive belt from below.


Stick a 14 mm wrench on the tensioner pulley and twist it counter-clockwise to loosen the belt. There's a hole on the bottom once you fully loose the belt that fits a 5 mm hex key nicely. This holds the tensioner pulley, so you can remove the wrench. Now you can easily slide the belt off without trying to hold the pulley as you do so.


Once the belt is clear, if you aren't sure if the water pump is indeed your issue, you can now freely spin the water pump pulley. Try to wiggle it side to side. If it doesn't turn easily, or has play when you wiggle it side to side, it's definitely not good.

Go back to the top, and remove the AC line bracket screw using a 10 mm socket and a long extension.


There's two black wires, one to the engine, and another tee'd off this that runs to the back. I'd remove both of these wires. You can leave them hanging from the upper left mount. There's a black connector on the ABS dohickey on the left. Pull the gray part of the plug up, it comes up about 1/2" or so, then the plug can be pulled straight back to remove. Just let it chill out there. It just needs to move down slightly to get a bolt out in a second.



The torque mount, the big black thingy, needs to be loosened at the engine bay side. Give it a few turns, but no need to remove it entirely.


Remove the upper engine mount bracket. Start by removing the bolt on the torque mount. Then completely loosen the three bolts on the upper bracket. The top one also bolts down a small black bracket that goes to the right, where it's held in place with two nuts. Remove the two nuts and the small black bracket. Then remove the one bolt that holds the small aluminum bracket that's bolted under the black bracket by the the two nuts. Now slide the upper engine mount forward to clear the torque mount bracket and remove. I left the bolts in so they didn't wander or get mixed up. I also stuck the two nuts back on the engine mount bracket so they didn't get lost, and threaded the single bolt holding the small aluminum bracket back into the engine for the same reason. (in some pictures the small black and aluminum brackets are missing, cause I put the bracket back in and forgot them, then had to remove the one bolt so I could re-install them)





Remove the 5 bolts holding the lower engine mount bracket. Leave the pictured bolt for last, this is the troublesome one. Once the first four are out, noting where they go cause there are several different lengths, remove the 5th bolt. This will hit the AC lines. Once it's free, make sure the bracket is loose, then gently pull the AC lines towards the side of the engine bay while wiggling the engine bracket to the side and towards the rear of the van. You need to get the bolt to the left, and then the right side of the bolt can wiggle free under whatever it's stuck on as you wiggle and twist the bracket towards the back of the vehicle. Once the bolt comes free on the right side, it'll lift up and out. Removed picture shows the 5th bolt. Once out, I put the other four bolts into the holes so I'd know where they went and set this off to the side.



Should now look more or less like this.


Remove the tensioner and idler pulleys. The tensioner pulley is easiest to remove from below. This is a left-hand threaded bolt, so turn it clockwise to remove it!!! In the below picture it's already removed. Then remove the idler pulley. This may be easier to reach from the top, but can also be removed from below as shown. This is a normal bolt, turn it counter-clockwise to remove. Set both pulleys off to the side, and leave the bolts and dust covers with them in the proper orientation and position. The tensioner has only one dust cover, the orientation of which matters. The idler pulley has two, the orientation of which doesn't matter, but they are two different sizes, one of which is on one side, the other on the other side. Don't mix them up (the FSM lists sizes and which one goes where if they do get mixed up).


Drain the coolant. Place a drain pan of some sort under the center of the van. Look behind the radiator at the base. There's a plastic drain cock. Loosen this, there's no need to remove it completely. Coolant will start to drain. It almost lines up with the hole in the splash guard, but some got on the guard and drained out of holes on the sides. Take note, some extra containers or rags may be useful.


Once drained, remove the clamp on the radiator hose, then slide the hose off the metal tube. I was able to grab the hose and twist it to break it free, then it slide off easily. Set this off to the side. I'd recommend stuffing a rag in the opening to avoid junk getting in it like what happened with mine.


Remove the two nuts holding the metal tube onto the thermostat housing with a 10 mm socket, extension, and ratchet. The top back nut is fun to re-install later...



When installing, be sure to not install the idler pulley first like I did, or you can't get the tube on and need to remove the pulley again.


Remove the thermostat. I grabbed it with a pliers cause it was stuck, which bent it, but I was replacing it anyway, so it didn't matter. When reinstalling, be sure the jiggler valve is up (the little loose metal piece near the top).


Limited to 20 pictures per post, so breaking here.

The thermostat gasket has a partial slot in it, it goes around the thermostat. Use a new gasket when installing, regardless of if you choose to re-use the thermostat or not.


Remove the clamp from the water outlet hose.



Now remove the thermostat housing. There's two bolts and a nut. You can remove the water outlet hose first, but I couldn't get a good enough grip on it to do so. I removed the bolts and nut, then the housing was stuck on the metal tube o-ring. I needed to use a screwdriver and a hammer to gently tap this left where it meets the metal tube. Once the housing was loose, I could move it back far enough with the outlet tube installed that I could grab the tube, twist it to break it loose, and then slide it off. I screwed the nut back onto the water pump stud, and placed the bolts back in the thermostat housing so they wouldn't get lost.


Once removed, you can now see the thermostat housing gasket and outlet pipe o-ring. Both of these need to be replaced when installing the new pump. Be sure the grooves are clean when installing the new ones. Both of these should be included with your new pump. I didn't realize and bought them separately.




There's a plastic guard over whatever this is behind where you just disconnected the water outlet hose. I had trouble with the water pump here. I got the pump out but couldn't get it back in without removing this guard. Go figure. Held in place with two bolts, use a 10 mm socket and ratchet to remove.




Now you have to remove the water pump pulley. There's a special tool for this I mentioned in post #25, but it's $400. There's other similar tools that are much cheaper that should work. I used a locking pliers over one of the bolts, pushed up against the shaft, and this held the pulley still while I cracked the three other bolts. Then remove the pliers, rotate the pulley, clamp down on one of the loose bolts, and crack the fourth bolt free. When installing, finger tighten the four bolts, then clamp onto one and tighten the other three. Remove, rotate pulley, clamp onto another bolt and tighten the last bolt.



Once the pulley is loose, we can now get to the main event, removing the failed water pump. There's a 16 bolts, some hard to get to. Like this one my 3/8" ratchet wouldn't fit. Luckily I had another one that did. A 1/4" ratchet would probably be better here. Or a 12-point combo wrench. I had a 6 point combo wrench in 10 mm but the 6 points didn't give me enough room, and the open end wouldn't fit securely on the bolt. One of the other lower ones a 12 point wrench came in quite handy, which I happened to have a 12 mm wrench in 12 point.

As you remove the bolts, a recommendation I found here was to lay out the new pump, and as you remove each bolt place it in the same hole of the new pump. There's three different bolts here, so you don't want to get them mixed up.




At this point, as the pump bolts were removed, it started leaking coolant. This was a bit messy, and break out the drain pan(s) again. I think if you loosened the two engine block drain plugs, this wouldn't leak here, but I didn't want to spend the time to find these, especially as the coolant was changed on my van ~13k miles ago. All in all, this job still needed two gallons of coolant, and the system holds three, so I swapped 2/3rd's of the coolant. Not bad.



Once all the bolts are out, tilt the back end out, rotate it up, and lift the pump out.




Congrats! The pump is now removed! Pat yourself on the back and take a break. You're halfway done!

Also we've reached the 20 picture limit again, so I'm going to go check on dinner and eat. More to come.

Once the pump is out, the gasket may be stuck to either the pump or the engine block. Mine was stuck to the engine block, but came off easily.


Here's my two pumps. Note the new one is sitting on a rag, so the sealing surface on the bottom doesn't get scratched. The new pump, as mentioned, is Aisin, bought from Rockauto. The old pump is made by Aisin for Toyota. It's stamped both AISIN and TOYOTA. The Rockauto one is stamped AISIN but where TOTOTA is on the old pump there are grind marks. From searching, it appears Aisin just makes these with the Toyota stamp, and any not sole to Toyota have the marks ground off and are sold to 3rd parties like Rockauto and other auto parts stores. If you buy this from a Toyota dealer, the Toyota shouldn't be ground off though.

Note the old water pump holding all the bolts for me. I originally used the new water pump to hold these bolts to remember the locations. Once the old pump was out, I carefully transferred over all the bolts to the old pump to hold them instead, so I knew where they went on the new pump.


Clean off the gasket sealing surface on the engine, and you're ready to install the new pump. At first I tried to install it while holding the gasket on, but I couldn't get it in. It was hitting that plastic guard I told you to remove earlier. I tried putting the pump in without the gasket, but no luck. That's when I removed the plastic guard. However, I still seemed to have issues with clearance with the gasket on the pump, so I took the gasket back off and put it in without the gasket. Same as for removing, with the long part of the pump up, slide it down like so, then rotate it into position.

Be sure that when you install the new pump, you've put the old pulley on it first. But do not put any of the bolts on it. Just slide it over the shaft and make sure it doesn't fall off. Once the pump is installed, the pulley can no longer fall off. But that also means you can't put it on, either. If you put the bolts on the pulley outside the engine, which is tempting, then you can't install a couple of the water pump bolts. So put the pulley over the pump shaft, don't install any of the bolts, then slide the pump and pulley down into the engine bay and into place.


Once rotated down, it sit nicely for me here away from the engine. This made putting in the gasket easy.


I carefully slid the gasket into the space between the pump and the engine block. I held it lined up and threaded in this bolt up front, and brought it close to, but not quite, touching. Once this bolt is in, it holds the gasket lined up on the front of the pump. I repeated this by putting in one bolt in the rear of the pump. Once these two bolts are in, the gasket is "locked" into place, so you don't need to worry about it slipping out of alignment anymore. However, I kept both bolts just not quite touching, to leave the gasket room to shift slightly until I got the rest of the bolts in.


I then installed all the rest of the bolts, except the two "C" bolts, which spec Three Bond 1344. I used Loctite Blue, which is equivalent, but held off on that just yet. Once all except the two were installed, I tightened them all finger tight. I used a socket held in my fingers to do this.


Now I started torquing down all the bolts. I started with gently hand snugging the "A" bolts with a wrench, then did the same to the B bolts. I then broke out a torque wrench and tightened down the "A" bolts first, then the "B" bolts. I couldn't fit a torque wrench on all of them, so some I had to just use a combination wrench and estimate the torque, which I did by slightly loosening then re-tightening the same amount a bolt I had previously torqued with the torque wrench to get a feel of how tight it should be. The tsienna manual for the 2nd gen has out-of-date torque specs, the new torque specs are 15 ft-lb for bolts "A" and 8 ft-lb for bolts "B" and "C".


Now I applied Loctite blue to the threads of the "C" bolts, and installed them and torqued them down. After this, I re-checked the torque on all the rest of the bolts I was able to, and double checked the torque on these last. But note you have like ten minutes before the Loctite starts curing, so that's why I waited to install these bolts till last.

Also note that the manual doesn't specify an install order for these bolts, the order and steps I did this in is based on my previous experience tightening things.


Congrats! Your new water pump is installed! Now just reverse all my previous removal instructions starting from tightening down the pulley on the new water pump using the locking pliers in the previous step. As you go, things important for the installation process were put in bold print.

Still to come - the coolant fill and air bleed process. But that'll have to wait till tomorrow.

Oh, torques for re-assembly:

• Idler pulley - 40 ft-lbs
• Tensioner pulley - 35 ft-lbs
  • I couldn't get a torque wrench on this. Probably why Toyota specs a SST for this, which is just an extension. But the SST changes the torque spec since it adds length. If you do this, refer to the FSM or do the calculations to adjust the torque accordingly.
• Water pump bolts - 15 ft-lbs
  • Same note if you use the SST that's an extension for this, which I did not. I just hand tightened them
• Wheel lug nuts - 76 ft-lbs

I think there were some other torques specified, but none I really cared enough to use a torque wrench on, personally. If you do, refer to the FSM.

Okay, so now it's all back together, ready to rock, except the coolant is empty. First, reach back down behind the radiator and hand tighten the plastic radiator drain cock. Once that's done, locate the air bleeder valve near the thermostat outlet tube. This is a brass metal fitting with a hole in it. Put a wrench on this and crack it open about 1/2 turn or so. Don't remove it.


Oh, at this point I also removed the hose on the bottom of the coolant reservoir tank to drain the coolant in that too while I was at it. Reinstall the hose after if you do this.

Grab a funnel and start filling the radiator. You should hear air coming out of the air bleeder valve after a bit. Continue filling until coolant starts flowing out of the bleeder valve. You may get a few drops coming out, but what you want is a steady stream. Once this happens, go ahead and tighten that valve up.


Keep filling the radiator, slowly, until it's full and no more air is bubbling up.


Fill the reservoir tank up to the FULL mark. Install the radiator cap. Squeeze both of the big radiator lines by hand several times, and check the level of the coolant in the reservoir tank. If it's dropped, top back off to the FULL mark.

At this point I started the van and moved it out of the garage, shut it off, and used a hose to rinse out the engine bay. This is so if there were leaks later, I could see them and know it wasn't residue from the water pump replacement/drain process.


Now bleed the air from the cooling system. Start the van and idle it at 2500-3000 RPM. I used a stick to the armrest of the driver seat and tweaked the tilt and forward/backwards in really short bursts to set the idle speed.


It says to warm up the engine until the thermostat opens, and circulate coolant for several minutes. I waited until the engine was at normal temp on the gauge, then went for another 5 minutes or so. The radiator hose leading to the thermostat started getting hot and it felt like coolant was flowing. Once the engine is warm and coolant is flowing, squeeze both of the big radiator hoses by hand to help bleed air. USE EXTREME CAUTION! Hoses are hot, the one hose is right by the drive belt, so pay very careful attention you don't get your hand in the belt! And the fans may kick on at any time.

Now stop the engine, and wait for it to cool down completely. Check the coolant in the reservoir tank. It's probably lower than the FULL mark. Top back up to FULL. Check for any coolant leaks.

Congrats! You're done! I took a 20-ish minute drive after this, and several hours later it the reservoir was down about 1/2". I topped it up with the last of the 2nd gallon of coolant. Took another 20-ish minute drive home, and the next morning it was down another ~1/2". Did not top up. Drove about 15 minutes to work, and after work it still seemed to be about 1/2" down. I'll watch this over the next week or so every time I use the van in the morning, before it warms up. It may continue to drop as the last of the air works out. Once it stabilizes, you're good.

I'll try to review everything I've wrote in case I missed something, but I think it's good enough to figure out how to do it. Good luck, let me know if you have any other questions relating to this!

djjuniortai said:

Hi - thanks for the guide! I recently bought a 2012 V6 Sienna now at 183k miles. Carfax history doesn't show anything about water pump or thermostat being replaced. Some questions:

• Do they usually have signs that they are about to fail? I see you heard some metal tinging sounds and felt water pump pulley loose.
• Should I proactively replace these or should wait till I hear such signs of imminent failure?

Planning to replace the belt in the meantime since it's easier. Thank you!

Click to expand...

The main sign on mine was a soft metallic wobbling sound at idle when stopped. It was quiet enough that I could only hear it when stopped. Then the belt started squeaking for a few minutes on startup. Then I lost enough coolant to see the temp gauge go all the way to hot and bounce back and forth from hot to cold—not a good sign. I stopped the engine instantly. Called a friend, filled up with water, drove back to a shop, replaced the water pump, and it is still running good 2 years and 28,000 miles later.

After we got it back to a shop, I could see that the water pump pulley was visibly wobbling. If I had known what to look for, I might have spotted it before it got so bad.

I wouldn't replace it proactively, but if you're in there already e.g. changing the belt, I'd definitely consider it. Might be a good idea to watch the Car Care Nut YouTube videos on the Sienna, particularly the 2007-2010 model. It has the same engine as yours, and he talks about the water pump being somewhat common to fail.