Does the smoke coming fom Lisa's tail pipe spell doom?

Dear Car Talk

Dear Car Talk | Jul 01, 2007

Dear Tom and Ray:

I have a 2001 Dodge Intrepid with about 110,000 miles. I have the oil changed regularly, but recently noticed smoke coming from my tailpipe when I take off from a stop. This doesn't happen all the time, but it's enough to make me nervous. I know the car has a lot of miles, but other than that, it runs well, doesn't make any funny noises and idles pretty quietly. I do have to add oil between oil changes. Should I be super worried? Any suggestions for what I can or should do without spending a lot of money? -- Lisa

RAY: Well, I can tell you two things for certain, Lisa. First, you're burning oil. That's the smoke you see coming out of the tailpipe from time to time.

TOM: Second, it's not coming out from time to time, it's coming out every time you accelerate.

RAY: You may not notice it all the time because of the wind, or because you're -- get this -- paying attention to the road in front of you instead of looking for smoke in your rearview mirror. But I'm pretty sure it's blowing smoke all the time, because that's what cars do when they're burning enough oil to be visible.

TOM: What you do about it depends on how much oil you're burning. You say you're adding oil between oil changes. Are you adding a quart every 2,500 miles? In that case, you've probably got a long way to go before this becomes a crisis. The car could go for tens of thousands of miles. Or something else could end this car's life before your oil consumption ever does.

RAY: Right. Like a transmission failure. Or a run-in with a FedEx truck.

TOM: But if you're adding a quart every 300 miles, then you're already in a holding pattern circling the boneyard, and air-traffic control might clear you for landing there any time now.

RAY: In either case, you want to make sure you keep the crankcase full. Check the oil level frequently -- even more often than you think you need to -- because your oil consumption can increase suddenly, and you don't want to run out of the stuff. Plus, when the crankcase is full, the engine will burn less oil. That's because the lubricating work is spread among four or five quarts, instead of two, three or four. When there are fewer quarts, the oil has to work harder, which means it gets hotter and burns faster.

TOM: Also, keep changing the oil. A lot of people will say to us, "Well, I'm adding a fresh quart every week; why should I ever have to change the oil again?" The answer is, you can't decide which oil -- the old or the new -- the engine is going to burn. Itgoing to burn a mixture of new oil and old oil, leaving you with an engine full of the same mixture. So you still need to drain that old stuff out on a regular basis and refill it with new oil.

RAY: And you'll find that fresh, new oil burns more slowly than cruddy, old oil. So changing the oil frequently, and keeping it topped off, are two inexpensive things you can do to extend the life of the car.

TOM: But you've got an engine that's burning oil. And whatever stage it's at now, it's only going to get worse with time. So keep a close eye on it. And when you get to where you're adding a quart of oil every 300 miles or less, start looking at the '02 Intrepids. Good luck, Lisa!

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