Heat shield repairs. Also, the Geo Prizm.

Dear Car Talk

Dear Car Talk | May 01, 1993

Dear Tom and Ray:

I have a 1984 Volvo GL with 119,000 miles on it. Lately, I've noticed that when my car is cold, it sounds like a tree limb is dragging underneath it After about a mile, the noise is gone. The car runs great, but I would like to know what is causing this strange sound. I have looked underneath and there is no limb there.

TOM: I've read about this in my medical journals, Nicole. Doctors call this a "phantom limb."

RAY: Actually, Nicole, what I think you're hearing is a loose heat shield. Like most cars, and the Starship Enterprise, this Volvo has a heat shield on the catalytic converter. But this car also has several additional heat shields on the front exhaust pipe. And our vast (or at least half-vast) experience tells us that that's probably the cause of the rattling noise.

TOM: What happens is that the heat shield, which is a thin piece of metal, loosens up over time, and starts to rattle. It's worse when the exhaust system is cold, because things shrink when they're cold. After a mile or two, the exhaust pipe heats up, things expand, the heat shield tightens up, and the rattling stops.

RAY: The time honored remedy of backyard mechanics is to just tear the heat shields off. But we'd recommend you ask your mechanic to weld it back together for you. Good luck, Nicole.


RAY: You may know that Chevy and Toyota build a car together in California. At Toyota dealers, they call it a Corolla, and at Chevy dealers, it's called the Geo Prizm. But the Prizm is the one we recommend.

TOM: Except for minor details, the Corolla and Prizm are the same exact car. And it's a very nice car. The engine is smooth. It handles well, and rides well. It's got a decent amount of room and is pretty comfortable for a small car. It's got an airbag, optional anti-lock brakes, and it's put together well...just what you'd expect from a Toyota.

RAY: It's obvious that they thought this one through before they built it. It's got a lot of little features that are great, too. Besides cupholders and places to put your stuff, it's got height-adjustable seatbelt harnesses, so short people don't have to drive with the shoulder belt across their mouths--although I must say, I consider that a real advantage when I drive with my brother.

TOM: So, you may be wondering, if they're the same car, why are we recommending the Geo Prizm over the Toyota? Because for some inexplicable reason, the Geo costs $1,000 less! We don't know why. Maybe Toyota is charging a premium for the Toyota name and its reputation for quality.

RAY: Or perhaps Geo is trying to beat the Japanese at their own game; selling a car at a loss, or for not much profit in order to build market share, and develop and stable of happy, satisfied customers. GM's hope is that these customers will come back and maybe buy a real Chevy someday.

TOM: Whatever the reason, we suggest you take advantage of it. Although I'm not a fan of small cars, if you're looking for a good quality, modestly priced small car, the Geo Prizm is one you definitely have to look at.

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