This week, what makes that body rattle?

Dear Car Talk

Dear Car Talk | Apr 01, 1990

Dear Tom and Ray:


I have a 1985 Mitsubishi Galant which has developed a chatter when I accelerate, back up, stop at a stop light, or even just rev the engine to 3000-4000 rpm. The transmission was replaced less than a year ago and the mechanic has checked it thoroughly and found nothing wrong. Any ideas?
Robert

RAY: The fact that you continue to hear this noise even when the car is stopped (when you're idling at a light) suggests that it's a "body rattle" rather than something in the transmission. And the piece most likely to rattle and chatter on a car of this age is the "heat shield," a metal covering under the car that surrounds the catalytic converter.

TOM: In some ways, the heat shield is a carry over from ancient times. Back then, cars lived in grassy meadows and forests and had to hunt for their food. The heat shield kept the hot parts under the car from touching grass and leaves and starting a fire.

RAY: Well, my brother is embellishing the theory of evolution a bit, but that IS what the heat shield does. It also keeps the heat from rising UP into the passenger compartment and cooking the brown-bag lunch you left on the console between the seats.

TOM: Have your mechanic inspect the heat shield. If it's come loose, he can either weld it or replace it. Either way, it's a relatively simple repair.

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