The Shaking LeBaron

Dear Car Talk

Dear Car Talk | May 12, 2015

Dear Car Talk:

I have a 1988 Chrysler LeBaron convertible. I had a remanufactured 2.5-liter engine installed. The engine vibrates. The engine and transmission mounts were replaced, and the vibration is worse; I can really feel it in the steering wheel. The dealership said the shop that installed the engine might not have reset the timing in the two balance shafts. In addition to that, what else would cause the engine vibration?

-- Lin

Wow. An '88 Chrysler LeBaron. I just had a Ricardo Montalban flashback.

I'd suggest that you go back to the shop that installed the engine, and have them figure this out for you, Lin. Since you bought a remanufactured engine rather than a used engine, it should perform like a new engine. Certainly, it shouldn't be shaking the car enough for your hands to look blurry when they're on the steering wheel.

If you came to my shop with this problem, the first thing I'd do is check your compression. Actually, the first thing I'd check is your credit limit. But after that, I'd make sure that the compression is good in all four of your cylinders.

If one cylinder has low compression, you'd essentially be running on three and half cylinders. That definitely would cause the engine to shake.

Another thing I'd check for is a vacuum leak. It's not unusual, when you remove and replace an engine, to accidentally crimp a vacuum hose or forget to reattach one. A vacuum leak also would cause the engine to run roughly and shake.

On modern cars, a vacuum leak would turn on the Check Engine light and set a code. But your car's so old that the Check Engine light's probably been on since 1991.

There is a balance shaft in this car that's run by one of the timing belts. If that belt is off by just one tooth, the balance shaft will be out of sync, and it won't be able to do its job and dampen the vibrations.

Unfortunately, the only way to check that is to remove the front covers of the engine, remove the timing belt and start over ... lining up the belt and the timing marks from scratch.

If it turns out the valve timing is the cause of the shaking, then the remanufacturer really should bear the cost of the repair. The valve timing is set at the factory, before the engine is shipped, so your installer would not be at fault there.

But if he's a good guy, he'll call the remanufacturer on your behalf, explain the situation and make arrangements for the remanufacturer to pay him for the repair -- letting you off the hook.

And, obviously, if the engine compression is low, that's the remanufacturer's fault, too. But in that case, the engine's going to have to go back to the factory ... for re-remanufacturing. Good luck, Lin.


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