Q. I would like to change the PCV valve on my 2001 Caddy DHS but can’t find it. Can you tell me?
J.G., Chicago
A. You will never find it because your car doesn’t have one.
Q. Are maintenance-free auto batteries really free of all maintenance or should their fluid level (beneath the two rectangular caps on top of the battery) be checked periodically and distilled water added as needed? If so, how often?
D.N., Lake Forest
A. Yes, maintenance-free batteries are, well, maintenance free. There is no need to check the electrolyte level because the battery is designed so none evaporates. If you are looking for something to occupy your idle hands, our pickup needs to be waxed.
Q. I have a 2001 Ford F-250 HD 7.3-liter diesel with 109,000 miles that occasionally will not start. It will turn over. When it does start, it runs fine. And if I turn it off and start up again, it takes off fine. If I let it sit overnight, the truck will not always start the next morning. I have replaced the fuel filter. When I took it in to the mechanic, it started every time so he couldn’t find anything wrong. It is sitting in the driveway unable to start. I plan to take it to another mechanic, and I am hoping it won’t start there so they can get to the bottom of it. Do you have any suggestions?
K.K., Marengo
A. We have a hunch there is a problem in the glow-plug system. When the engine is cold (cold block, cold cylinder heads, etc.), it is difficult to ignite the fuel by compression alone. The metal absorbs much of the heat created. To help get your diesel started, glow plugs in the heads are turned on. You should see the indicator light glowing on the dash, too. On most Fords, the glow plugs may stay on up to seven minutes though the light will go out much sooner. During subsequent starts, when the engine is not so cold, glow plugs are unnecessary.
Q. I replaced the original tires on our Lexus LS430 with Dunlop SA2 tires, but after three days, they were replaced with Dunlop SP 5000 tires–same as the originals. After this, I noticed a vibration through the steering wheel. The salesman from whom I purchased the car agreed, but the shop foreman said nothing was wrong. A second dealer said the same. I returned to the tire store, where they installed Goodyears, but the vibration did not go away. I am at wit’s end.
M.L., Downers Grove
A. We can pretty much rule out the tires because three types have behaved the same. That leaves the wheels or spindles as suspects. One of the wheels may have been damaged in the mounting process. Or the lug nuts may have not been tightened evenly, creating run-out, which causes wobble, at the mating surface. Ask your tire dealer to have all of the rotating components checked out with a dial indicator, which measues runout.
Q. I have a 2000 Cadillac Deville. Between oil changes, I have to add oil to keep the level full. If the oil-life monitor is reading 45 percent oil life before I add one quart of oil, why does it still read 45 percent after? Is the monitor bad or are they just not quite as great as the manufacturer claims,and should I go back to the tried-and-true three months or 3,000 miles?
C.B., Morris
A. Adding a quart of oil is not like changing it. Though it may extend the oil life somewhat, it is not that significant. All of the junk and crud remain in the engine.
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Bob Weber is an ASE-certified Master Automobile Technician, having recertified every five years since 1978. Write to him in care of Motormouth, 17717 Silcott Springs Rd., Purcellville VA 20132. Send e-mail, including name and town, to motormouth.trib@verizon.net. Answers will be supplied only through the newspaper.
