Our van feels "Darty" or twitchy" on the highway

[ARCOgraphite]

Originally Posted by 1911CHAMPION
I keep the Coopers aired up at 36 psi.

The darty problem was not noticed until after the second alignment in April which was shortly after I had taken the snow tires off and put the all seasons back on.

The van drove fine after the new shocks and struts but something in the front was clunking. I replaced all moving parts in the suspension/steering that at the time I thought could cause the clunking. Now the clunking is gone and it feels solid but the darty problem started.

If I have time this weekend I'll rotate tires.

Thanks for the suggestions!


That reads like way too much PSIG

Also possibly loosen and retighten the lCA bushing when the car is Level with weight on the tire/wheel.

And after a car being up in the air and dangling, I'm always getting air in struts and it seems to
take forever for then to settle down.

Also, are the strut coil spring pigtails in their perches properly?

I hate Mac struts; unless every thing is perfect the car steers like a crash waiting to happen.

Also make sure you have slight toe IN. Maybe have someone load up the tires by pusing them outwards and dial it
till you see near ZERO toe approaching from the negative side. Some alignment guys will let you "help" if your not much of a pest.

- Ken

 

[1911CHAMPION]

Originally Posted by ARCOgraphite
Originally Posted by 1911CHAMPION
I keep the Coopers aired up at 36 psi.

The darty problem was not noticed until after the second alignment in April which was shortly after I had taken the snow tires off and put the all seasons back on.

The van drove fine after the new shocks and struts but something in the front was clunking. I replaced all moving parts in the suspension/steering that at the time I thought could cause the clunking. Now the clunking is gone and it feels solid but the darty problem started.

If I have time this weekend I'll rotate tires.

Thanks for the suggestions!


That reads like way too much PSIG

Also possibly loosen and retighten the lCA bushing when the car is Level with weight on the tire/wheel.

And after a car being up in the air and dangling, I'm always getting air in struts and it seems to
take forever for then to settle down.

Also, are the strut coil spring pigtails in their perches properly?

I hate Mac struts; unless every thing is perfect the car steers like a crash waiting to happen.

Also make sure you have slight toe IN. Maybe have someone load up the tires by pusing them outwards and dial it
till you see near ZERO toe approaching from the negative side. Some alignment guys will let you "help" if your not much of a pest.

- Ken




Door sticker says 35 psi Front and back. They're all measuring 34.5 - 35 cold currently (using digital tire pressure gauge and checked this morning before leaving for work and it was 65° Outside).

Coil springs are nested in the strut perches correctly. I checked before installing them and looked again last night.

I'm going to rotate tires first see if that changes anything, then swap two snow tires on front and if still no difference then I have some ideas on how to check the big control arm bushing at home before taking it into a repair shop. Prying on it with a pet bar only motivates it up or down vertically. Can't get in there to pry it left/right relative to vehicle centerline.

I'll report back by some time this weekend.

 

[wag123]

Originally Posted by 1911CHAMPION
Originally Posted by ARCOgraphite
Originally Posted by 1911CHAMPION
I keep the Coopers aired up at 36 psi.


That reads like way too much PSIG


Door sticker says 35 psi Front and back. They're all measuring 34.5 - 35 cold currently (using digital tire pressure gauge and checked this morning before leaving for work and it was 65° Outside).
Having owned a gen2 Sienna for almost 16 years, and having gone through several sets of tires in over 180k miles, I can tell you for a fact that 36 psi is not nearly enough on this van, as many other owners have attested-to on the Sienna forum. At the 35 psi that Toyota recommends, and at the 36 psi that the OP is running, the gen2 Sienna will wear the front tires on the inner and outer edges relentlessly, indicating underinflation. The van is simply too heavy for the 35 psi that Toyota recommends. If not rotated, a gen2 Sienna owner can wear-out a pair of front tires in only 12k miles if kept at 35 psi. In a VERY long thread on the Sienna forum, many owners experimented with tire pressures to find the sweet spot for tire wear as well as traction, handling, and braking performance. Some owners even did contact patch testing. It was mostly agreed that 40-42 psi in the front tires would even-out the tire wear and improve performance (at the cost of a marginally firmer ride), and it was mostly agreed that 40-42 psi was too high for the rear tires and 37-38 psi was the sweet spot. After several sets of tires, I can absolutely confirm these findings. I started out running 40 front and 37 rear but noticed that the front tires were still wearing to the inside and outside a little (but VASTLY improved over 35), so I went up to 42 front and 38 rear. I now get excellent tire wear and life. Rotating them, I got over 50k miles out of the last set. I'll bet that you haven't gotten anywhere close to that on your Sienna Champion.

 

[wag123]

I should have added that, on AWD Sienna models, the tire pressure should be kept equal on the front and rear. A good compromise is 41 psi all the way around on gen2 AWD Siennas.
I also should have added that is is best to rotate the tires from front to rear ONLY on Siennas, not side to side. Some brands of tires can have problems related to running them in an opposite direction then they were originally installed, as 40w8 pointed out.

 

[1911CHAMPION]

Originally Posted by wag123
Originally Posted by 1911CHAMPION

I keep the Coopers aired up at 36 psi.

I'll bet that you haven't gotten anywhere close to that on your Sienna Champion.


I remember reading that article on sienna chat and actually aired all 4 up to 38 and ran em for a while up until the end of last last year. The Cooper CS5 Grand Tourings are rated for 80,000. new tread depth was 12/32 they're still all measuring about 7/32 with my tire gauge and there are about 40,000 miles on these tires. Oddly there was a slight shake in one of the tires that I could feel until doing all this suspension work. Now they're smooth as glass.
I Fully expect to get 60k plus out of this set.

 

[wag123]

Originally Posted by 1911CHAMPION
Originally Posted by wag123
Originally Posted by 1911CHAMPION

I keep the Coopers aired up at 36 psi.

I'll bet that you haven't gotten anywhere close to that on your Sienna Champion.


I remember reading that article on sienna chat and actually aired all 4 up to 38 and ran em for a while up until the end of last last year. The Cooper CS5 Grand Tourings are rated for 80,000. new tread depth was 12/32 they're still all measuring about 7/32 with my tire gauge and there are about 40,000 miles on these tires. Oddly there was a slight shake in one of the tires that I could feel until doing all this suspension work. Now they're smooth as glass.
I Fully expect to get 60k plus out of this set.
The really long thread was on the old (now defunct) Sienna forum. Many owners were very unhappy with the tire wear they were seeing. That is exceptionally good wear for the tire pressures you are running. It is a testament to how good the Coopers are. My current tires are Coopers and they are wearing well. Previously, I only ran Michelins. This last time I decided that spending over 50% more for the Michelins on my high mile van was not a wise investment. I chose Coopers because I have always had very good luck with them going back to the 70'S.

 

[ARCOgraphite]

Originally Posted by 1911CHAMPION
Originally Posted by wag123
Originally Posted by 1911CHAMPION

I keep the Coopers aired up at 36 psi.

I'll bet that you haven't gotten anywhere close to that on your Sienna Champion.


I remember reading that article on sienna chat and actually aired all 4 up to 38 and ran em for a while up until the end of last last year. The Cooper CS5 Grand Tourings are rated for 80,000. new tread depth was 12/32 they're still all measuring about 7/32 with my tire gauge and there are about 40,000 miles on these tires. Oddly there was a slight shake in one of the tires that I could feel until doing all this suspension work. Now they're smooth as glass.
I Fully expect to get 60k plus out of this set.


Wow 35psig is surprising unless its for fully laden rear uprating..

That means the tires are likely undersized if toyota spec a pass car tire here.

This doenst take LT tires?

What are the OEM tires size? 235 65R 16?

- Good luck anyways. I seem to fight this same problem on may cars. Had to toe my FWD jetta to near zero to get rid of excessive front tire wear on the outside.

 

[another Todd]

Originally Posted by stroked93
Caster is off, that gives you the stability on the highway. look at the lower control arm bushings as they wear on a front wheel drive it will pull the wheel forward under power as those bushings flex and move.


Caster was the first thing I thought of also. Could have been altered with the new struts.

 

[wag123]

Originally Posted by ARCOgraphite
Originally Posted by 1911CHAMPION
Originally Posted by wag123
Originally Posted by 1911CHAMPION

I keep the Coopers aired up at 36 psi.

I'll bet that you haven't gotten anywhere close to that on your Sienna Champion.


I remember reading that article on sienna chat and actually aired all 4 up to 38 and ran em for a while up until the end of last last year. The Cooper CS5 Grand Tourings are rated for 80,000. new tread depth was 12/32 they're still all measuring about 7/32 with my tire gauge and there are about 40,000 miles on these tires. Oddly there was a slight shake in one of the tires that I could feel until doing all this suspension work. Now they're smooth as glass.
I Fully expect to get 60k plus out of this set.


Wow 35psig is surprising unless its for fully laden rear uprating..

That means the tires are likely undersized if toyota spec a pass car tire here.

This doenst take LT tires?

What are the OEM tires size? 235 65R 16?

- Good luck anyways. I seem to fight this same problem on may cars. Had to toe my FWD jetta to near zero to get rid of excessive front tire wear on the outside.
IMO, the passenger car tires ARE undersized given the weight they are asked to carry, especially in front. The standard tires are P215/65R16 on the gen2. I upsized mine to P235/60R16 (same diameter but wider and with a higher load capacity) on my second set. The gen2 Sienna's weight will typically exceed 5000 lbs for a 2WD carrying 4 passengers, and more than 5600 lbs in an AWD with 7 passengers, luggage, and a full tank of gas. 35 psi in the Sienna's tires is FAR too low to carry this kind of weight. Sometimes it isn't wise to follow a manufacturer's tire inflation recommendation when it is clearly inadequate.

 

[1911CHAMPION]

Well...

After crawling around under the van for about 2 hours this afternoon I believe the culprit is worn rack and pinion bushings. I restrained the left and right wheels with ratchet straps to the chassis and there seems to be a lot of left and right movement in the steering rack when my helper (wife) gently turned the steering wheel left and right with the van in neutral and holding the brakes.

The control arm bushings are solid. I pried on them every direction I could and they barely budged. I am confident I found the problem causing the twitchy behavior on the highway. I had my wife hold the steering wheel as hard as she could while I He-manned the tires left and right on each side. There is definitely some movement and it's not in the control arms; and it's definitely not in anything else cause all those parts have been replaced.

Steering rack bushing were probably not on anybody's radar I can imagine, but I'm pretty positive that's the culprit.

Thanks for all the help and suggestions! Motivation for me to get under the van again and take another good look.

Thinking I'll ratchet strap the steering rack towards one direction and take it for a spin and see what happens.

 

[1911CHAMPION]

It's one of the tires...

The steering rack "fix" made no improvement.

I rotated the tires front to back side to side (X pattern) and now it feels planted in the front and kinda "wonder-y" in the back.

So congratulations to whoever suggested that it was the tires. I'm guessing it's just one Though. I'll swap front to back on one side and then drive it and vice Vera to narrow down the one that causing the issue.

Definitely would prefer to replace only 1 or 2 tires instead of The entire set.

Firestone All seasons any good? They're $70/ea on Amazon right now. The reviews on TireRack are mixed. Curious if those would be a suitable replacement for a pair on the Sienna so I can at least have a matching pair of tires on each axle....

 

[wag123]

Originally Posted by 1911CHAMPION
It's one of the tires...

The steering rack "fix" made no improvement.

I rotated the tires front to back side to side (X pattern) and now it feels planted in the front and kinda "wonder-y" in the back.

So congratulations to whoever suggested that it was the tires. I'm guessing it's just one Though. I'll swap front to back on one side and then drive it and vice Vera to narrow down the one that causing the issue.

Definitely would prefer to replace only 1 or 2 tires instead of The entire set.

Firestone All seasons any good? They're $70/ea on Amazon right now. The reviews on TireRack are mixed. Curious if those would be a suitable replacement for a pair on the Sienna so I can at least have a matching pair of tires on each axle....
For safety's sake, always replace tires in sets of two and put them on the same axle.
IMO, the Coopers are better than the Firestones in the Sienna's size. I didn't pay much more than that at Discount Tires for the Cooper CS5s I have now. You may be able to get a warranty adjustment on the bad tire.
I suspect that you may have run into the Cooper tire problem that 40w8 suggested. I have heard this before, and it isn't just Coopers that can have the directional-set problem. It appears that this mostly occurs on on heavier vehicles. Several people complained about this in the Sienna forums and this was even known to occur on the OEM Michelins and Dunlops. On Siennas, I strongly recommend that when you install them on one side, keep them on the same side. I mark my tires.

 

[1911CHAMPION]

The Coopers locally are $102/ea at Discount tire plus mounting and balancing
For $80 more (4x$70) I can have a new matching set of tires if I get the Firestone's. More or less inclined to go that direction.

It's been YEARS since I've driven on Firestone tires. I would be venturous enough at this point to give them another try...

I 100% agree that the 98 load rating In this tires size for this vehicle is definitely not adequate. I use my van like a pickup truck. Hauling stuff, helping people move, road trips with the family occasionally while trying to reduce mileage accumulation on our 2016 Sienna. And I occasionally tow a 5x10 steel trailer with a ramp tailgate hauling lawn mowers and landscaping materials, it's not light.

These Cooper tires have been put through a lot in the last 4 years! They've been thoroughly tested and they were definitely an improvement over the Goodyear Assurance Fuel Max tires that came on the van when we bought it.

 

[ARCOgraphite]

I'd throw some LT tires on there.

 

[SpitFire6]

Good, you got it sorted and it wasn't the tracking toeing out too much dynamically.

 

[wag123]

Originally Posted by 1911CHAMPION
The Coopers locally are $102/ea at Discount tire plus mounting and balancing
For $80 more (4x$70) I can have a new matching set of tires if I get the Firestone's. More or less inclined to go that direction.

It's been YEARS since I've driven on Firestone tires. I would be venturous enough at this point to give them another try...

I 100% agree that the 98 load rating In this tires size for this vehicle is definitely not adequate. I use my van like a pickup truck. Hauling stuff, helping people move, road trips with the family occasionally while trying to reduce mileage accumulation on our 2016 Sienna. And I occasionally tow a 5x10 steel trailer with a ramp tailgate hauling lawn mowers and landscaping materials, it's not light.

These Cooper tires have been put through a lot in the last 4 years! They've been thoroughly tested and they were definitely an improvement over the Goodyear Assurance Fuel Max tires that came on the van when we bought it.
The Coopers have really gone up since I bought mine. I paid $82/ea for the 4 upsized P235/60R16 Cooper CS5 Grand Tourings at Discount Tire about 2 years ago. The grand total out the door with mounting/balancing, valve stems, road hazard, and tax (and tax) was about $500.

 

[1911CHAMPION]

Update:

The rack and pinion bushings are shot!

It wasn't tires... I wasn't ready to cough up $400 without further investigation.
I even took it to a reputable local auto repair chain and they couldn't find anything loose, at least they didn't charge me... And the technician said he could "feel" it during the ride along.

Link to video showing the movement in the rack when turning wheels left and right parked in the garage.

https://youtu.be/JJPrZj7NCiM

Polyurethane bushings are on order and I'll get those replaced as soon as I can!

I also just had to replace the oil cooler line so that's why the underbody looks so oily. Pin hole leak in the oil cooler line pushed out probably 3+ quarts.