I guess my 06 Sienna is about as dinosaur as it gets, I've never heard of vacuum mounts, hydrolic yes but vacuum... that sucks... drum roll please. That seems about as over achiving as upgrading standard headlight fluid to synthetic.

Does/has anyone acualy felt a differance?

 

Yeah it's odd. Installing a solid mount in place of a hydraulic mount really helps to tighten up overall engine response in an older car, but with the added side effect of slightly more engine noise and vibration in the cabin at idle and lower RPMs. Personally, I prefer that, but it's not exactly ideal in a family vehicle.

 

The mount wears so that's up for discussion. If the air intake flapper thing hasn't given you trouble for 300k miles, why mess with it now? If you must, there's discussion in the mods section about how to disable the flapper leaving it in the wide open position. Folks swear doing so adds up to 50hp!

Sixto
04 LE FWD 237k miles

 

Interesting you bring that up. I'm not looking for more performance, it's got plenty of power 😅

However, since I have two vehicles with the same engine, I get a lot of opportunities to compare them side-by-side, and the Sienna often feels noticeably somewhat sluggish off the line and at lower RPMs compared to the Highlander (although some of that could be attributed to the larger-than-stock 235/65R16 tires vs the stock 215/65R16 size, but the Highlander is also AWD, so.... 🤷? I abhor the "whale on rollerskates" look with the 215s).

I've also been concerned about a slight rattling noise the engine makes at WOT, which stops right at ~4500 RPM, consistently... Which is about where the intake runner butterfly valve (ACIS?) activates. It's not piston slap, I'm reasonably certain of that. Definitely gonna check that system out, though, since the Sienna has a junkyard engine out of a 2010 that looks like it sat outside for 3 years 😑

 

I honestly never realized there was such thing as a vacuum-actuated engine mount… let alone such a device in our mid-2000s minivan. Learn something new every day!

Do we think that extra complexity is mostly/entirely in the pursuit of lower noise in the cabin?

I bring all this up in the hopes that I’m not the only shade-tree who feels mystified (on a regular basis) by “new” vehicle tech that’s probably pretty common and basic in 2008 let alone now. I see a lot of good points made in this thread and I’m definitely curious of any results that come from experimenting with, say, a solid mount like OP mentions.

 

You know, it could be a vent for air in the cushion chamber of the mount. I think this is being over thunk, actually.

 

I honestly never realized there was such thing as a vacuum-actuated engine mount… let alone such a device in our mid-2000s minivan. Learn something new every day!

Yeah, lots of extra complicated things going on under the hood for sure. If this was German, it would be far more complicated and require attention every 50k miles 😂

Do we think that extra complexity is mostly/entirely in the pursuit of lower noise in the cabin?

Oh, absolutely. I poked around some more last night, I guess the 3rd gen Sienna has this system too... Which is really weird, because our Highlander (which is the same gen as the 3rd gen Sienna) doesn't have this system and is somehow more quiet than my Sienna, even with all the dynamat I installed.

I bring all this up in the hopes that I’m not the only shade-tree who feels mystified (on a regular basis) by “new” vehicle tech that’s probably pretty common and basic in 2008 let alone now. I see a lot of good points made in this thread and I’m definitely curious of any results that come from experimenting with, say, a solid mount like OP mentions.

It's less mystifying when you look back and realize how much of what controls the engine (points, dizzy cap/rotor, coil, wires, etc) all required servicing at some point or another, and how all of that has been consolidated into a couple sensors and individual coil packs. I think it lends credence to why modern vehicles routinely hit 200k miles with little service required.

Electronics in general are far more reliable than the equivalent mechanical systems they replaced. The catch is that they are more expensive to repair and can be a pain in the ass to trace if you don't have a degree in EE (which I happen to have 😅).

 

I honestly never realized there was such thing as a vacuum-actuated engine mount… let alone such a device in our mid-2000s minivan. Learn something new every day!

Same, I had to loosen those mounts when I replaced the water pump on our van and never paid attention to it.

Sienna often feels noticeably somewhat sluggish off the line and at lower RPMs compared to the Highlander

Weird, we find our Sienna to be more responsive than our 2016 Higlander.

My wife was the first one to complain about the Highlander being sluggish.

 

Weird, we find our Sienna to be more responsive than our 2016 Higlander.

My wife was the first one to complain about the Highlander being sluggish.

Interesting! I'm assuming your Highlander is also equipped with a 2GR-FE? If so, do either of them make any abnormal buzzing noises between 3000-4500RPM at wide open throttle? I also see your Sienna is AWD - what about the Highlander, is it FWD or AWD?

 

The thing is, the main difference between the Sienna and the Highlander is that the Highlander's main market is the SUV/truck market. The Sienna market is the soccer mom/road trip market. If you've ever done a long road trip in a pickup truck vs. the Sienna, you will know why I am working so hard to keep my Sienna on the road. I want my Sienna to run and drive like a Sienna, NOT a Highlander. Could you change them out? Probably. It's entirely possible the PWM logic has a feedback circuit to the ECU and you'll get a make/model-specific code. It's also possible that there's some sort of different P/N for the valves. Specifically, the flapper valve might have an emissions effect if you were to change that. If you live in a State with emissions testing, that would likely be an automatic fail. Of course, it's up to you. However, if you DO decide to do it, let us know how it works out!

 

The thing is, the main difference between the Sienna and the Highlander is that the Highlander's main market is the SUV/truck market. The Sienna market is the soccer mom/road trip market. If you've ever done a long road trip in a pickup truck vs. the Sienna, you will know why I am working so hard to keep my Sienna on the road. I want my Sienna to run and drive like a Sienna, NOT a Highlander.

About that - we've taken both cars on the same 500–mile roadtrip route more than a few times each (not at the same time, just custody schedules). The Sienna drives wonderfully, but the Highlander handles it just as good. The cars were loaded with the whole family and all the kids' stuff every time for a 1:1 comparison. The kids (5 of them) vastly prefer the Sienna for obvious reasons (space, roof mounted screen, space, softer ride, space, etc), but both cars are quite good on roadtrips.

Could you change them out? Probably. It's entirely possible the PWM logic has a feedback circuit to the ECU and you'll get a make/model-specific code. It's also possible that there's some sort of different P/N for the valves.

I'm still waiting on my new Denso radiator to come this week, so I won't be able to test it until this coming weekend. I'll test it with them unplugged to see if the computer throws a fit. If it does, I'll leave them plugged in and tucked away somewhere. Or install a dummy load. We'll see what happens ¯\(ツ)/¯

Specifically, the flapper valve might have an emissions effect if you were to change that. If you live in a State with emissions testing, that would likely be an automatic fail. Of course, it's up to you.

Luckily, I know the local inspector personally 😅

However, if you DO decide to do it, let us know how it works out!

I plan to! Like I said before, I'm not looking for performance or "sick gains" 😂, I've got motorcycles for that. I go to the MR2 forums for 2GR-specific things anyway, those guys know their way around the 2GR blocks.

My '94 Accord had one.

Yeah, a lot of cars have these things... My most notable one was a failed hydraulic mount in my 1992 Ford Taurus (which this van ultimately replaced). A solid rubber mount made a world of difference, especially with its boat anchor Vulcan V6; way more responsive, and you could definitely feel the drivetrain had tightened up.

Weight?

The Highlander (Limited AWD 7-seater) is over 300lbs heavier than the Sienna (LE FWD 8-seater), at 4508lbs and 4177lbs, respectively.

 

The Highlander (Limited AWD 7-seater) is over 300lbs heavier than the Sienna (LE FWD 8-seater), at 4508lbs and 4177lbs, respectively.

Final drive ratio? Your Sienna's U151 is 3.08. Is your Highlander's U660F 4.154? That would make a very big difference.

 

Check exhaust heat shields starting with the manifold and cat shields for buzzing.

Sixto
04 LE FWD 237k miles

 

I can assure you it's not that 😅. The noise is consistently between a very specific RPM range, only with heavy throttle, and immediately disappears at ~4300RPM.

Here's a video I took last year, it's the same issue as this guy.

I did some data logging on the Highlander earlier this evening to see how the timing advance does in a known-good 2GR-FE. Again, once my radiator comes, I'll take the Sienna out and do the same data logging and compare the two. I'm also replacing the tiny filters in the oil lines (factory metal lines 👌), plus the VVT solenoid o-rings as they're leaking pretty good; all those bits were ~$30. Might as well knock it out while I'm in there.

Also - Anybody know how to pull the variable runner flap thing out of the upper intake plenum without destroying the thing? I pulled the plenum off to get at the solenoids and the flap motor looks like it's glued in. Maybe I'll yank the Highlander's upper intake to "test" it.... I threw 12V at it though and it seems to work 🤷‍♂️

 

Definitely ADHD. But I like it! How far we've come from the powerglide

 

Good news, my new Denso radiator came today! A day early! And a new Gates rad cap, of course.

Too bad, though, I still have to wait for the weekend anyway. Got 5 kids, 2 of them are sick with strep, and 2 more of them have birthdays on Saturday and Sunday (celebrating late because sick).

I hope I can remember how everything goes back together 😂

 

Good news, my new Denso radiator came today! A day early! And a new Gates rad cap, of course.

Too bad, though, I still have to wait for the weekend anyway. Got 5 kids, 2 of them are sick with strep, and 2 more of them have birthdays on Saturday and Sunday (celebrating late because sick).

I hope I can remember how everything goes back together 😂

I've been facing the same exact issues... Wife's car needed an oil change. She finally took it to the mechanic because we kept having rainy weekends and kid obligations. Then she asked me to work on her friend's car, but we still have the same rainy weekends and kid obligations. My van has been sidelined while waiting for a new rear axle beam. I finally got it on Monday. Wouldn't you know it... rainy weekend coming up! Mother's Day is the weekend after that and it has me thinking I'm taking a day off to do car stuff sometime soon.

 

Replacing the beam axle is done under the car. Put on some waders and you'll be fine in the rain

Are you keeping the original springs or original rated springs?

Sixto
04 LE FWD 237k miles

 

Replacing the beam axle is done under the car. Put on some waders and you'll be fine in the rain

Are you keeping the original springs or original rated springs?

Sixto
04 LE FWD 237k miles

I only fish saltwater, so I don't have waders.

I'm currently planning to swap out the bushings with new ones, transfer over the backings and shoes, transfer over the hubs (which are relatively new), install new shoes and hardware, disconnect and replace the shocks, pop out the springs, drop the exhaust, rug up some kind of brace/shield/hanger to keep the beam from falling on my exhaust when I disconnect it, disconnect any hangers, brackets, or wires clipped onto the beam, put the wheels on the new axle, drop the axle, then roll the new one in there. The springs actually look pretty good, but, if I discover that they are rusted or broken when I pop them out, I may get some new ones. If I do it right, most of the work will be done before I actually try to do the removal and reinstallation of the beam itself.

 

Got a few things done tonight before tomorrow's radiator job.

All 4 VVTi solenoid o-rings changed out (pretty sure zipties would have made better seals than these ancient artifacts, they snapped right off):

Also installed new VVTi filters. Naturally, they were both clean as a whistle:

My youngest decided his car also needed fixin':

Don't worry, we learned about proper jack safety afterwards and how to use jackstands; we don't want that 20-pound beast of a car coming down and crushing the little dude... Luckily he was wearing his super-awesome Mohawk helmet.

I didn't have time to get to the cooling system today since I ran out of light, and I've gotta get an early start tomorrow since we have a lot going on. Then I can finally test the intake flaps and motor mount (needs a new vacuum line anyway).

All that, and she's ready to go for tomorrow (I should really take a pressure washer to the engine bay, it's filthy in there):

 

Finally completed the radiator job! Took her on a test drive after everything was put back together and refilled with coolant. I plumbed the vacuum motor mount directly to the intake vacuum source, and rerouted the pre-filter intake flap to the vacuum tank so it stays open at all times. Didn't really notice anything different in drivability. I also left the ACIS flap (inside the upper plenum) unplugged, and the ~3000-4500 RPM "clattering" at WOT disappeared entirely. Not sure exactly what that means. Didn't really notice a difference there, either, besides the lack of noise. Plugged it back in and the noise returned... So I unplugged it again. We'll see how that goes over the next week or so.

Also, the van has been leaving mysterious fluid drops on my driveway the last several months, and I found the source - a heater hose between the engine and one of the tee fittings that was leaking at the engine side and running down the backside of the transmission:

I had installed some screw type clamps as a temporary measure after replacing the tee fittings last year. That was replaced with a new length of heater hose and proper constant-tension spring clamps. The backside of the transmission was absolutely covered with coolant-infused dirt and grime, only really visible after pulling out the air filter box. I was almost certain it was the transmission pan leaking, but apparently I was wrong. Still going to keep an eye on it though.

 

Final result of the vacuum line re-routing looks factory enough to pass the visual inspection portion of the emissions test here in Utah:

The ~2.5" length of vacuum line between the motor mount's VSV to the motor mount itself was hard as a rock, and cracking pretty badly, so there wasn't really a difference in drivability after bypassing that VSV at that point (I stuffed the line from the filter box into the dried up short line). Today though, I finally had a chance to run a fresh line into the mount (had to use a 1/4" windshield washer fluid line and 1/4" to 3/16" vacuum line adapter to mate it to the filter box line), and HO-LEE SHIT did it improve the drivability! It drives almost like my wife's 2015 Highlander 😂. Almost. No more low-RPM-high-load "bouncy" downshifts, and the previous clunkiness has been all but eliminated. So if your van feels a bit too clunky when shifting, check that vacuum line between the mount to the VSV. It's probably leaking. Or the mount is shot. You decide!

Anyway... There's a lot of slack left on the line from the filter to the adapter, and normally I would trim and route it better, but we've got a 500-mile roadtrip tomorrow morning, and I'm sore and tired 😅. The slack has been secured with a zip-tie to a bracket just off the subframe, out of the way of any errant fan blades. No CEL since I removed the VSV, either.

And finally - the other day, I had a brief conversation with Marc of Frankenstein Motorworks, regarding the ACIS being noisy when activated. He knows the 2GR-FE inside-out (even tunes Sienna ECUs for MR2 engine swaps, you guys should check out his youtube channel), and he suggested just leaving it unplugged as it won't trigger a CEL at all. Seems to be a common thing with MR2 guys. So I'm leaving it unplugged indefinitely. I may even swap the upper intake to a 2GR-FXE unit, as that intake doesn't even have ACIS; but that's another project for another day.

Also had my little helper with me before dinnertime, gotta teach them young:

 

Another update:

Over Memorial Day, I was perusing the local junkyard's fresh shipment of 2nd gen Siennas when I came across a decent-looking 2008 with the 2GR. Poked around the engine bay for anything useful and, on a whim, decided to peek at the VIN tag. Turns out the engine happened to have a VIN from a Japan-built 2008 Lexus RX350 (Do all 2GR-FEs have those godforsaken brackets on the back of the intake manifold?? Mine doesn't have them at all, and pulling the junkyard intake was not a fun time)

Since the ACIS in my intake was being problematic (making odd clattering valvetrain-like noises when activated), I bought the junkyard intake for a whopping $35 and swapped it over. Plugged in the ACIS that had been previously left unplugged due to said noises, and gave her a good whooping around town. I'm happy to report that the odd clattering noises are gone, replaced with happy 2GR noises, and - at least according to the butt dyno - uphill performance feels slightly improved as well.

I also decided to plumb the engine mount vacuum directly to the vacuum tank instead of the filter box, and I can't say I've really noticed a difference in NVH while idling, neither in Drive nor Park. But she sure pulls harder at WOT now, so that's nice.