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Q: I drive a 1994 Toyota Celica with 111,000 miles on it. About six months ago, I had the radiator replaced, because it was cracked and leaking. Today it exploded! I took it back to the same mechanic who installed it, because it was under warranty. The mechanic told me that he has never seen a defective radiator in all of his vast (six years) experience. He stated that the most probable cause was that my motor was bad and caused too much pressure to build up in the radiator, causing the massive and totally unforeseen explosion. He told me that if it is indeed the engine, if he puts in a new radiator it will just explode again in a couple of days. He also said there is no way to test this faulty-engine theory other than waiting to see if the new radiator explodes.
As I’m sure you can understand, I’m not too excited about the idea of driving around for a couple of days, waiting to be stranded on the side of the road again. My question: Does a bad engine really cause a radiator to explode, and is there any other way to test this theory? Any insight you may have into this situation would be much appreciated. Laura
Ray: Well, your mechanic is right that something is indeed wrong with your engine, and that it would be unwise to just replace the radiator.
Tom: But he’s wrong about testing it. There is a way to test it other than just driving around and waiting for the new radiator to explode.
Ray: I suspect you have a bad head gasket, Laura. You say that you replaced the radiator about six months ago, so my guess is that before you got around to replacing that radiator, the engine overheated — maybe several times. And that’s what caused your head gasket to fail.
Tom: What’s happening now is that pressurized exhaust gases are leaking out of the cylinders and getting past the broken head gasket into the engine’s cooling passages. That’s building up tremendous pressure in the cooling system — much more than is supposed to be in there. Usually when this happens, we see a cooling hose burst off before the radiator explodes, but I guess your hoses were on there pretty tightly. Our compliments to your mechanic for really tightening those clamps!
Ray: So now here’s what you have to do. Your mechanic has to put a new radiator in the car — at least to do the testing. You can’t do a head-gasket test unless you get the engine up to operating temperature, and you can’t do that without a working radiator.
Tom: Once the radiator is in there and the engine is warmed up, he can take his emissions-testing wand and hold it over the radiator opening. If we’re right, the hydrocarbon reading should go bonkers, because you’ve got exhaust gases — including unburned gasoline — pouring into the cooling system.
Ray: Then you can decide if you want to spend $1,000 on a head gasket for this car — plus the cost of a new radiator. I know you have a radiator warranty, but the radiator company will argue — fairly — that this wasn’t the radiator’s fault. So unless you bought the optional Radiator Explosion Rider, add a radiator to the bill, too, Laura. And good luck.
Question: Years ago, I read in the newspaper that you should not set your parking brake if there is snow on the ground or a freeze warning in the area, because the brake pads could freeze to the wheels. My uncle thinks I’m crazy for believing such a thing. He says there is no way for a metal or ceramic brake pad to freeze to a metal wheel. Who is correct? Justin
Ray: Well, fortunately for family harmony, Justin, we can say you’re both right.
Tom: Your uncle is right that there’s no way the brake pads can freeze to the rotor and keep the car from moving. But the cables that operate the parking brake can — and do — freeze.
Ray: In a lot of cars, the cables run under the car and are attached to levers that actuate the caliper, or the brake drum. And under certain wintry conditions, snow or slush can cover the levers or get inside the cable sheaths, and then freeze overnight. Then when you try to release the brake in the morning, the brake handle in the car moves, but the parking brake doesn’t.
Tom: So, when you’re driving in slushy conditions, with a chance of a freeze overnight, you’d be wise to park your car on a flat surface and avoid using the parking brake that night.
Ray: But you don’t want to make a habit of that, because there’s another kind of freezing that happens. That’s freezing due to rust. If a parking brake goes unused for a long period of time, rust can build up in the cables or on the levers. And then when you need the parking brake, it just won’t move.
Tom: So, our advice is to make a habit of using the parking brake all the time — except when there’s wet snow or slush on the ground and the temperatures might drop below freezing. In those instances, we recommend not using the parking brake, and then calling in sick the next day so you can stay home and watch your car to make sure it doesn’t roll away.
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