Click and clack's response to "Is my husband nuts?"

Dear Car Talk

Dear Car Talk | Feb 01, 1991

Dear Tom and Ray:

I feel stupid asking you this question, but I think my husband is nuts. He tells me to put oil into the gas tank of our 1980 Chevette. He says this will make it run better, but every time I do it, the car smokes and backfires. Please tell my husband that I'm right.

TOM: Well, Carrie, this is one of those good news, bad news situations. The good news is that you're absolutely right.

RAY: The bad news is what you're right about; your husband is indeed nuts. For decades, people have been adding things like "Marvel Mystery Oil" to their gasoline. No one knows exactly what it does; I guess that's why it's called mystery oil.

TOM: Actually, it's a "top end lubricant." That's a light weight oil designed to coat the upper parts of the engine--the intake valves in particular. What your husband is doing is using motor oil as a top end lubricant. And as you can tell from all the smoke and backfiring, motor oil is much too heavy for that purpose. Basically, you're making your car run like it burns a lot of oil.

RAY: But we should at least consider the possibility that your husband is not a complete nut, Carrie. Maybe he's just embarrassed to have the only Chevette in town that ISN'T burning oil. He may just be showing his compassion; making the car backfire and belch blue smoke just so all the other Chevette owners won't feel so bad. What a nice guy, huh?

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