Dear Tom and Ray:

I own a 1988 Isuzu Trooper II that has 74,000 miles on it. A few months ago, we noticed that it was leaking antifreeze. No one can pinpoint where the leak is coming from. There is always coolant in the reserve tank. The hoses are fine and the head passed a stress test. We can smell the antifreeze near the front of the car after we've driven it and parked it. And a mechanic did find some antifreeze in the number three cylinder. Is it dangerous to drive? And will it be expensive to fix? -- Beverly

Tom: No, and yes.

Ray: Here's the story, Beverly. I think you have several leaks. The "internal" leak in your number three cylinder is by far the more serious of the two.

Tom: That's not the leak that you're smelling. But it's the one that's going to cost you many hundreds of dollars to fix. So you want to address that one first.

Ray: The coolant probably got into the cylinder through a blown head gasket or a crack in the cylinder head. I don't know what kind of stress test your engine passed (was your mechanic running on a treadmill while he worked on it?), but it couldn't have passed a bonafide head gasket test and still ended up with coolant in a cylinder.

Tom: It's not dangerous to drive. The worst that will happen is that you'll eventually run out of coolant and the engine will melt. But you can prevent that from happening for a long time by simply keeping a close eye on the antifreeze level. Just make sure you check the level in the radiator itself (when the engine is cold!), since a leak could prevent the reserve tank from giving you an accurate reading.

Ray: Eventually, however, if you want to keep this truck, you're going to have to fix the internal leak, and that's big bucks.

Tom: Your other leak, the "external" leak that you smell, could be coming from anywhere. But based on my experience, I'd look carefully at the "weep hole" of the water pump.

Ray: It may be an insignificant leak, because a very small amount of antifreeze can create a lot of antifreeze smell.

Tom: And it'll look even more insignificant next to the new cylinder head you need. So explore that internal leak first, Beverly, and make sure you plan to keep the car before fixing the small stuff. Good luck.

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Tom and Ray share secrets mechanics don't want you to know in their pamphlet Ten Ways You May Be Ruining Your Car Without Even Knowing It! To order, send (check or money order) to Ruin, P.O. Box 536475, Orlando, FL 32853-6475. You can also order online.

© 1997 by Tom and Ray Magliozzi and Doug Berman Distributed by King Features Syndicate, Inc.

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