QDear Tom and Ray:

My wife accidentally put about 3.5 gallons of diesel into her nearly empty 1998 Honda Odyssey. Upon realizing her mistake, she filled up the rest of the tank with gasoline. At that point, she wisely decided to call me before trying to drive it. I immediately called two mechanics to get their advice. I first called the dealer, and he said not to drive the car and to have it towed in. He said he would have to drain the gas tank and steam-clean it to get the diesel out and then check to see how far into the system the diesel fuel might have gotten. Then I called my trusty curbside mechanic. He said that we probably could drive it. It would smoke some while the diesel burned out, but he thought that it might be okay, except maybe we would have to replace the oxygen sensors. What should we do before driving it? -- Neil

ARAY: Well, I think the dealer gave you the correct advice, Neil. But you may not need to be quite as thorough as he's suggesting. And you certainly don't have to let him do the work, if you like your buddy, Crusty McToolbox, better.

TOM: It sounds like your wife never even ran the engine with the diesel fuel. So we can say with confidence that none of it got into the fuel lines. All of it's still in the tank.

RAY: The tank needs to be removed and drained. You can probably skip the steam-cleaning phase, as I'm guessing that less than half a cup of diesel will remain on the fuel-tank walls.

TOM: After you reinstall the tank and refill it with gasoline, I'd have Crusty remove the fuel line where it joins the fuel rail, up in the engine compartment. Then you can cycle the fuel pump (without running the engine) and take a sample of the fuel in a glass bottle. Let it settle out and see if it looks clean. Do this several times, or until you get good, clean-looking gasoline. Then hook everything back up and drive it.

Dear Tom and Ray:

I'm part of the male population that, in the past, you have politely referred to as "anal-retentive" when it comes to car care. I'm getting better, though. However, this one is killing me. I have an '86 Mercury Grand Marquis that runs great but is getting long in the tooth (224,000 miles). In order to keep a closer eye on things, I installed temperature and pressure gauges. At highway speeds, the temperature hovers around 210 degrees on warm days. Should I be worried? If not, what would be considered the point at which I should start worrying? -- Garry

RAY: When you see plumes of steam wafting up from your engine compartment, Garry.

TOM: Actually, you're nowhere near the worrying point. Worry when it gets up to 240 or 250 degrees.

RAY: Under pressure, antifreeze doesn't boil until it hits about 260. So, 210 is absolutely fine. You're in no danger of overheating this old beast.

TOM: But more important, Garry, I can see you've still got work to do. Are you staying with the 12-step anti-retentive program we recommended?

RAY: Or are you still stuck repeating the first step over and over again to make sure you've got it right? If so, it may be time to call your sponsor, Gar. Remember, one day at a time, baby.

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(c)2004 by Tom and Ray Magliozzi

and Doug Berman