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Vibration from front end

5K views 17 replies 8 participants last post by  bmconway76110 
#1 ·
Just took the first half off a road trip from Reno to Denver in my 2005 Deville DTS. On the way out Reno, about an hour into the trip I got a noticeable vibration in the steering wheel. I check the TPMS and all of the tires were at 38/39 pounds. I pulled over and used my hand held tire gauge to drop the pressure to 34. It help a lot. Has anyone else had this issue?

The second odd issue was when I pulled off the highway in Denver I hit some of the worse railroad tracks I have ever experienced in my life, and I hit them hard. I thought I had blown a tire put it turns out the car had actually died. Dash was off, engine was off. I pulled over, put it in park and it started up fine.. I took the car into Firestone and the front and right rear were way out of alingment. They aligned it and balanced the tires. Vibration is still there but I know they put more than 35psi in the tires. Could over inflation be the cause?

Also, I checked for codes and there were none. I am wondering if my hand flew up and hit the ignition when I hit the tracks.
 
#2 ·
38/39 PSI is WAY too high. Proper pressure, checked COLD, is listed on the drivers door.

Over inflation can amplify a vibration, but not cause one. The cause is an out of balance rotating part: damaged rim/tire, corrosion buildup between the rim/rotor/hub mating surfaces... A bad motor mount (usually the front mount) can also cause vibration..... Gone over hundreds of times here and in the Eldo/Seville forums.

FWIW, if the tracks are what threw the alignment off, one or more steering/suspension components are damaged. Rims and especially tires may be as well.
 
#3 ·
Firestone gave me the before and after on the alignment and it all back in spec. I drove it out to Blackhawk and it drove straight as an arrow, just the annoying vibration over 60ish. I will check the cold pressure in the morning. I wonder if a Road Force Balance would help. The tires have plenty of tread on them but I have only had the car 5 months or so. Could be there is a bad belt. Since lowering the air pressure seems to reduce the vibration I am inclined to think wheel/tire over motor mount. I did put it in neutral at highway speed and it didn't seem to make much difference.
 
#4 ·
I think your car is spec'd for 30 psi tire pressure, COLD. Never check and/or bleed tires when hot - the cold inflation pressure recommendations take the normal temperature pressure rise into account. That recommended pressure is an all-around ride quality-tire life-handling-gas mileage-braking figure. Some people cheat a bit and run 32 psi cold (Me, for one).

On your tire sidewall is a "maximum cold inflation pressure" stamp. That would (could) be used for your Bonneville Salt Flats speed runs - but at no other time.
 
#7 ·
I have to drive back to Reno this weekend. Will make sure the tires are at 30 PSI when I leave and see how she rides. Keep in mind the vibration showed up before I hit the tracks and Firestone looked everything over. I had told them I hit the tracks so they had a chance to try to find something wrong and do the repair. Not saying they may not have missed something, just thinking its probably more of a tire issue then a suspension one.

Anyone have any thoughts on why it may have died when I hit the tracks.
 
#10 ·
Thanks MC. I wonder if its a computer thinking there was an accident thing, although you would think it would have called OnStar

Les Schwap has a road force balance machine. They offered to looked at everything and check the balance on the tires. I will run it over tomorrow while my friends are at work.
 
#14 · (Edited)
Problem solved. The Road Force Balancer showed all four tires out of round and one with a nasty high spot. They put four new tires on her and she was smooth as, we'll, a Cadillac on my short freeway run.

Next project will be to replace the leaking strut I noticed today, but that can wait for a while.

Thanks to everyone.
 
#17 ·
Problem solved. The Road Force Balancer showed all four tires out of round and one with a nasty high spot. They put four new tires on her and she was smooth as, we'll, a Cadillac on my short freeway run. .

Glad to hear your problem is solved. :cool2: I am having some hi-speed vibration issues as well, and I've got appointment for four new Michelin sneakers tomorrow.
 
#15 ·
Depending on the speed rating of the tires you installed (your car is set at a 130 mph limiter) you could get outta town and verify that the car is smooth to 100+.

Speed limiter setting - the tire rating on the driver's door sticker --------
 
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