PontiacBonnevilleClub.com

I've read enough around here to know that a vibration at highway speeds is not uncommon, but I was wondering if some more specific info might help me diagnose mine!

I've had this 2002 SLE for about a month now and it is running great. I do notice a vibration right around 70mph typically. If I speed up a little to around 72-73 or slow down just a few mph it goes away. It's kind of a wobble if that make sense. I can live with it if it isn't indicative of some larger problem. The car itself runs great and seems to be very well taken care of.

The vibration itself isn't bad...and I feel it mostly through the gas pedal. I don't feel it through the steering wheel at all. Does this help narrow it down?

I plan on taking this Bonneville on a road trip to Missouri over Memorial day, so I'm probably going to be having a mechanic take a closer peek soon anyway.

Also, I believe the LIM gasket has been changed to an aluminum one, but it still has Dex Cool in it. Should I be worried about this? (grin). Is there a general consensus on whether to flush and switch or leave it be if the gasket has been replaced? The car has approx 100,000 miles.

Flush the dex-kill asap. You are slowly deteriorating the lower intake gaskets and the plenum. I have a vibration I can feel under my pedal/floorboard. Most likely it is the wheel bearings. When (if at all) were they replaced?

Could possibly be a trans mount maybe, hard to say without seeing it.

PLAGUE PHANTOM wrote:Flush the dex-kill asap. You are slowly deteriorating the lower intake gaskets and the plenum. I have a vibration I can feel under my pedal/floorboard. Most likely it is the wheel bearings. When (if at all) were they replaced?

Don't know. I just got the car a few weeks ago. Carfax showed fairly religious oil changes at the dealership over the life of the car...and the I am fairly sure the Lower Intake gasket was changed to an aluminum one, but I have no clue about any other maintenance being done.

Look between the LIM and the head. If its a black gasket, its the old design. If its a silver/aluminum color, it has been replaced. But get that dex out.

How dose your front trans/engine mount look? Any oil seeping out of it between the two halves?

Hows the tread on your tires? Have you had the balance checked on them?

I won't have the chance to look at anything till Saturday....I do appreciate the replies and will update this weekend.

As far as the front trans mount...Is this visible from above? Not exactly sure where this is.

The tires look almost new as far as tread goes...they are Uniroyal TigerPaws.

wader2k wrote:I won't have the chance to look at anything till Saturday....I do appreciate the replies and will update this weekend.

As far as the front trans mount...Is this visible from above? Not exactly sure where this is.

The tires look almost new as far as tread goes...they are Uniroyal TigerPaws.

It is viewable from the top, but may not be able to see if its leaky from the top. Its right where the engine and trans bolt together and connects to the sub-frame behind the radiator.

Had the car over by a mechanic. Wheel hubs are showing no play. Front motor mount is needing replaced. All other looks clean. Mechanic said the vibration is most likely the mount.

Got a quote of $250 to have it replaced(along with some other minor items).

I'm supposed to be driving down to see my folks in 2 days. 1000 miles round trip. Shouldn't be a problem to drive it as is as I won't be getting the mount done for a few weeks?

wader2k wrote:Had the car over by a mechanic. Wheel hubs are showing no play. Front motor mount is needing replaced. All other looks clean. Mechanic said the vibration is most likely the mount.

Got a quote of $250 to have it replaced(along with some other minor items).

I'm supposed to be driving down to see my folks in 2 days. 1000 miles round trip. Shouldn't be a problem to drive it as is as I won't be getting the mount done for a few weeks?

More annoying than anything.

You can do a solid front mount with a long bolt, some washers, a couple bushings and 3 hockey pucks. most here have done it, gives the car a more positive feel. If you are interested in that, use the search function and poke around. Lots of posts out there about it.

That's hefty for a mount. How minor are those items?

nos4blood70 wrote:That's hefty for a mount. How minor are those items?

+ Fuel filter.....

I'd hate to see what they charged for the rear mount(s?).

You can seriously do it yourself if you have a couple wrenches and a jack. May take 30 min. And if you get the stock style mount from RockAuto with the club discount(basically covers shipping) you'll come in waaaay less than $100.

Id start with some of the basic maintenance items first; alignment and balance/rotate the tires.