Should I repair this oil leak when I can get by with just adding extra oil every few weeks?

Dear Car Talk

Dear Car Talk | Apr 01, 1995

Dear Tom and Ray:

I need some help making a decision. I own a 1984 S-10 Blazer 4WD. It leaks oil at a rate of about a quart every 1200-1500 miles. I have received an estimate of over $400 to have it repaired. I am not questioning the estimate--my question is should I bother to fix it? The truck has only 75,000 miles on it and has been well maintained. It looks and runs fine. And with one child in college and another on the way to college, I am looking to keep the truck for at least five more years. So, should I give my tax refund to my mechanic, or should I buy four or five cases of motor oil and keep my crankcase full?

RAY: The only oil leak I can think of that could cost 400 bucks to fix is a rear main engine seal. And that IS a complicated job. But before you do that, you should ask your mechanic to check your Positive Crankcase Ventilation (PCV) system.

TOM: The PCV system purges the crankcase of vapors. And if it's not working correctly, too much pressure can build up in the crankcase and force the oil out the rear main seal, for example. And we've found that many times, on modern cars, fixing the PCV system fixes the oil leak. So try that first.

RAY: If it still leaks, then there are two ways to look at it. The environmental approach would be to spend the $400 and fix it, because you're leaking oil onto the ground and you're polluting the environment. So no matter what size the leak is, it should be fixed right away.

TOM: The non-Sierra-Club-approved approach is to forget about it, because a quart every 1200 miles is really not much at all. And as long as you keep an eye on the oil level and keep it topped up, you won't do any damage to your engine.

RAY: So here's my suggestion. If the PCV solution doesn't stop the leak, put the $400 toward the first kid's tuition. Then convince the second kid to go to trade school instead of college, for a degree in auto mechanics. Then, after graduation, he or she can rebuild your entire engine for you. Because by then, you'll probably be leaking a quart every 12 miles.

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