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Automania/Repair & Maintenance
AUTO QUESTIONS AND ANSWERS FOR WEEK 49
by Bob Hagin
Q. I recently saw a locally produced TV show on simplifying your lifestyle. It showed a couple who had disposed of their late model car and now drive a 1964 Plymouth Valiant. Isn't it false economy to depend on such an old car for reliable transportation?
A. At 32, it would have to be in great shape before I'd trust it. Those shows don't fill in the details like maybe the pristine Valiant was a gift from Grandpa when he died. The idea seems idyllic until hot weather hits and it has no a/c. On the plus side, a pre-smog old-timer can be worked on at home, registration is cheap and so is insurance.
Q. My wife has a 1991 Chevrolet Lumina Z-34 with the dual overhead camshaft engine. I have had the alternator replaced two times within the last two years. The car runs flawlessly at all times but the cost of new alternators and the labor involved in replacing them is too much. I would replace it myself but it is buried at the bottom of the engine, between the block and the firewall. Because of the location, I don't think that the alternator is being cooled properly, even though there is a cooling fan for it. Could it be overheating? Any thoughts on saving my alternator would be appreciated.
A. You're right about that alternator being overheated by its location. I've had several letters like yours and as yet, now one seems to have come up with an answer to extend the life of the unit. But misery loves company and you have lots of it. Owners of other brands of General Motors vehicles have had the same problem. I'm told that the company is working on an updated and more reliable unit and it may now be available. Some of my readers have had success with alternators that have been rebuilt by independent shops but nothing seems to be foolproof. I think it's a case of a weak design that never should have been put into service.
Q. I purchased a 1985 Mitsubishi Galant new. It now has 62,000 miles on it and it recently started smoking from the tail pipe. Hoping to save money, I took it to an independent shop that is located close to my home. After discussing the problem with the mechanic (who is also the shop owner), he stated that the design of the engine was the problem since it has jet valves and they were causing the smoking. My car is still smoking after I got the bill for two new belts and four new jet valves. Do jet valves cause the engine to smoke? Can they be replaced without having to remove the cylinder head? The car doesn't smoke all the time, just after sitting for a long period of time or overnight.
A. Before you have anything else done, try using an internal engine cleaner like Rislone but follow the instructions. With only 62,000 miles in 11 years, it's possible that you haven't driven the car hard enough or often enough to keep engine deposits from forming around the piston rings. The jet valves on those Mitsubishis are part of the emissions control system. They pull a small amount of a very lean mixture into the combustion chambers at high velocity to "swirl" the main body of the incoming fuel to make it burn more efficiently. The jet valves can be removed without taking off the cylinder head but the valve rocker assembly has to be taken off first. The jet valves have their own small valve stem seals that keep them from leaking oil into the combustion chamber and they come preinstalled on new jet valves. If your Galant smokes after the jet valve replacement, I'd suspect that the valve stem seals on the intake valves themselves are worn out and leaking. To replace them, the cylinder head has to be removed and stripped. Getting the valves out can be a hassle because the ends of the stems sometimes develop burrs that have to be removed first by hand-filing.
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