01 Jetta TDI: Shimmy / Vibration / Shake

ERICKTDI · February 21st, 2009, 18:06

I am at a dead end and can't figure out this problem. Hopefully someone can help???

Over the past 5k miles or so our car has developed a nasty shimmy, shake, or vibration most noticable between 35 and 45 mph under acceleration. The vibration is minimal (if at all) when braking or coasting. I am set to get new tires and an alignment but want to resolve the vibration first.

Here is the car info...
We have a 2001 Jetta TDI that is bone stock with 188,000 miles. Maintenance is up to date for timing belt service, brake fluid flush, auto transmission fluid flush and filter, oil, and intake cleaning. The front sway bar bushings were replaced in the last 10k miles. The shocks are stock original. The tires are 205/60/R15 and are due for replacement.

Attempts to diagnose...
I put the front end in the air and checked for any loose steering drivetrain or supension parts, none were identified. I rotated the tires thinking it was a wheel out of balance, no noticeable difference.

HELP PLEASE!!!

Thanks,
Erick

JASONP · February 21st, 2009, 18:09

Warped rotor?

roadhard1960 · February 21st, 2009, 18:52

Bad cv joints? If it is nasty can you drive on a 4 lane highway with someone watching from the second car. If you see wheels hopping about you might have a clue.

Where do you live? I live in a smooth road area so my suspension does not suffer the same way that a car driven in Ohio or Michigan might suffer.

cadman1940 · February 21st, 2009, 19:46

First thing to check is for loose rubber inside of tire. This is done with car jacked up in neutral grip tire top and bottom and very quickly switch top & bottom maintaining contact with tire note if you feel marbles inside tire if so remove loose rubber and rebalance assembly. Another possibility is a bent wheel this can be checked for by simply rotating wheel while holding a stabilized rod to determine runout or woble in wheel. A warped rotor will only cause problems when braking. These are just a few but the first ones I check when I have problems. Thanks cadman1940

ERICKTDI · February 22nd, 2009, 10:04

I have updates...

I just took the car for a 10-12 mile drive. The vibration is probably better described as a rhythmic pounding felt in the steering wheel. At parking lot speeds on a smooth surface it is very slow and results in a rhythmic tug on the steering wheel that jerks it about 3-4 degrees at each rotation of the wheels. Obviously as speed increases the piston like movement turns into a violent shake at 40 mph and then over 60 mph it is a smooth buzzing vibration. If I brake or accelerate the vibration does not change and by shifting into neutral and coasting the behavior continues with no change.

Based on all this I am leaning toward it not being a wheel balance, rotor, or drivetrain issue. It seems more like a bent axle, if that is even possible. If this were my old rear drive chevy I would say that a front spindle was bent?

Also to answer roadhard's question, yes we live in a pot hole prone area of Kentucky.

I am trying to figure if there is something on this car that I should target for diagnostics or if I am over my head and need an expert.

Thanks always for any help!
Erick

JASONP · February 22nd, 2009, 10:07

I'm still guessing rotor,let us know!
GL!

roadhard1960 · February 22nd, 2009, 10:27

Someone just mentioned a good idea. Jack up car. Spin every tire looking to see how true the tires are. Post results of runout. It is possible that you have more than one tire damaged or running out of true or out of round. Rotating tires might just put another bad tire in the same place. I had a set of tires where one tire would always cause a pull. When it was rotated to the back the pull went away. Same car never had tires that were all that true. Maybe the Brazilian GTI wheels were not that true to start with.

My brother has destroyed at least one tire in a chuckhole. It may be possible that you have done belt damage to more than one tire so that is the reason for inspecting each tire looking at them from the front or back and from the side while spinning. Weird wiggles and weird hump/high spots are problems.

ERICKTDI · February 24th, 2009, 15:21

And the winner is... Roadhard and Cadman.
After lifting the car and checking every possible suspension and drivetrain component for the third time I still found nothing. My fear was paying for 4 new tires and the problem not going away. I just got home from the tire place with 4 new tires and the problem is solved. It appears that the tread or belt had seperated in a tire which caused the vibration. When I rotated the tires the vibration went from not so bad in the rear to nearly unbearable when the bad tire was up front. Anyway, thanks again for the help.
Erick