another vibe question

[jcaps]

I have '99 Jetta VR6, 5spd, with 110K miles.

I get vibration in the front end that is felt through the steering wheel, shift knob, and a little bit in the floor at around 55 - 65 mph.

I only get the vibe when the engine is under load. It's more pronounced during acceleration, less but still persistent maintaining 55-65mph, and more pronounced if maintaining speed up a hill.

I can get the vibration under heavy load at lower speed (say 45), but the vibration seems to stop during cornering with heavy acceleration (gunning it on a sharp turning on-ramp).

No squeaks, rattles, or grinding.

coasting at any speed = no vibration.

The rims are not stock, but the tires are new, re balancing and rotating does not help.
The axles were replaced. no help.
Checked the dogbone (tranny mount). Looks great to me.


engine mounts?
springs?
shocks?
CV joint? inner/outer?


I would like to know how to pinpoint it without shotguning parts.

thanks,
Jeff

[vwmercer98]

check to see if your wheels are bent. mine does almost the same thing. i cant go past 85 or feels like the back end is bouncing. this will make the shift knob shake. i switched my wheels back and it went away. but bbs' look sick so i deal with it. see if it gets worse when you drive faster

[dewsburylad]

yeh i agree ..... or even a wheel bearing or the wheels may need balanceing

[jcaps]

The vibration stops over 65mph.
No change in vibration after replacing tires and re balancing and rotating them several times.
No vibration from the rear. Only the front.

So, to move things along, let's say it is not the tires, or wheels.


Without just replacing parts, how can I pinpoint it to something specific?




Thanks.

[mcrow]

check your engine/tranny mounts, they will send a good amount of vibrating if they are shot.

[jcaps]

Engine and tranny mounts look good. I removed, inspected and replaced the dogbone. All OK.

Did the wiggle test for the wheel bearings and Tie rods. All OK.

For argument sake we'll say these are all good:
- Wheel bearings
- Tie Rods
- Wheels
- Tires
- Balance
- Engine mounts
- Tranny mounts
- alignment
- Axles/CV joints


What's next?

[brokentoe]

rotors bent? maybe. them bent alittle will send a vibration.

[jcaps]

Originally Posted by brokentoe

rotors bent? maybe. them bent alittle will send a vibration.

hmm. The bakes have been replaced a while back (not for this problem). All new rotors and pads. Same vibe before and after.



I suppose a hub could be out of balance. Any way to check this at home?

[luism_12x]

I had the same problem with my car. My wheels are 17"s. Everything on my car is in great condition. I honestly came to the conclusion that mk3's are sensitive to wheels that weigh a lot. I have switched mine to stock and the vibrations goes away.

[jcaps]

Well, I guess I'll have to find a set of stock wheels to try.