Q. I have a 2000 Mitsubishi Montero with 3.0L V-6 and over 180,000 miles on it, and recently had oil smoke and oil leaks. The estimate for repairs was more than the value of the vehicle, so after a little research I used a "Stop-Leak" product from Bars, and for $20 solved everything. Do you think this fix will last?

A. At twenty dollars, you had practically nothing to lose. These types of additives cause the seals in the engine to swell, stopping the oil. The additive most likely fixed the oil smoke by restoring the valve guide seals and the external leaks by swelling the camshaft seals and other gaskets. At some point, the seals will fail and an actual repair will be necessary. I have used this product and seen thousands of miles before repairs were necessary. Good luck!

Q. My 2007 Toyota RAV4 has a loud, annoying rattle when the car hits 1500RPM at about 40 miles per hour. My mechanic checked the heat shields but that hasn't helped. What could it be?

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A. One area that may be a problem is with the drive belt tensioner. This is the device that holds the “fan” belt tight during normal engine operation. At certain speeds I have seen the tensioner shake and rattle causing this type of noise.

Q. Ever since I had my car battery replaced at a big parts store my car is making a funny noise when starting in very cold weather. Other times, at high speeds, the engine feels like it is straining. I have never had a problem with this car, which is a 2002 Toyota Camry with only about 52,000 miles on it. I took the car back for them to check and they assured me it was fine. They suggested it was the starter, but it never happened before changing the battery. Is there any possible relationship?

A. Since you didn’t have any of these problems before you had the battery replaced, I certainly would start with rechecking the battery. A garage should first test that the battery is fully charged (many new batteries are not). Then the mechanic should test the battery, starter and alternator for possible problems. I would also want to see a voltage drop test performed to test for possible poor connections. A poor engine ground could cause some of these symptoms.

Q. I am considering buying a mid-sixties car and I have always liked the Chevy Corvair, in spite of what Ralph Nader thought of the car. Do you have any suggestions before I start looking for a Corvair?

A. The Corvair is a fun car. I owned one for a while, but you do need to be careful of what you purchase. Corvairs can have plenty of structural rust problems and are notorious for oil leaks. They can also be a good bargain when compared to other 1960’s cars. The first thing I would do is go to a Corvair meet to talk with owners who know all about these cars. You may even find one for sale. In Massachusetts, a great resource is the Baystate Corvair Club or any nearby chapter of Corsa, the world wide Corvair club at www.corvair.org.

Q. I am in the market for two new front tires for my 1995 Honda Civic. I'm planning on buying a newer car this summer, but need new tires on my current car. Can you recommend a good place to buy new tires? Are there tires available that are new, but low-end, and will get me through 25,000 miles? I don't want to spend too much on this car, since I will be getting rid of it in three to four months.

A. Tire stores sell a wide variety of tires in a range of prices that should fit your budget and needs for your car. Since tires are made of petroleum byproducts, the cost of tires has gone up along with the price of oil. As a cost saving alternative you might want to consider visiting your local salvage yard and purchasing used tires. It is certainly possible for you to find a pair of tires with decent wear that will fit your car and budget.