Q–The thermostat of my ’89 Ford Taurus 3-liter has been changed three times with three brands. After each change, the meter reached about 40 degrees above the cold mark (normal) and seemed to be fine for a week or so. But after a couple weeks, the meter would only occasionally reach normal and would drop to cold suddenly and never get up again to normal. J.Z., Chicago
A–We think the problem is with the coolant temperature gauge or, more likely, the coolant temperature sensor. Ask your technician to test the sensor with an ohmmeter as the engine warms up. Another possibility may be corrosion preventing a good ground. If it checks out OK, he may want to carefully examine the wiring.
Q–You state (Motormouth, Oct. 16), “Though Honda recommends a 60,000-mile belt replacement on some engines, on others, it suggests 70,000 miles.” The higher interval is incorrect; it should instead read: “Though Honda recommends a 60,000-mile belt replacement on some engines, on others, it suggests 90,000 miles.” Generally, the longer interval is recommended on engines in recent model years. K.S., Chicago
A–We are gratified by the number of well-informed professionals (and well-above-average do-it-yourselfers) who read our column. Our biggest problem is finding the right keys on our keyboard. Thanks for putting us straight.
Q–I see where the recommended frequency of oil changes is 3,000 miles or three months, whichever occurs first. What is the significance of three months? Is four or five months OK?
Should oil be changed when it is warm/hot or cold. I would think cold is better because then every drop of oil is in the pan and drains more completely. Less oil in the filter, I’ve found, also reduces spillage. H.L., Naperville
A–Oil change intervals are expressed in time and mileage because it may take some people two years to drive 3,000 miles. Short trips are very damaging for the oil and ultimately the engine.
Regarding hot versus cold oil changes, the school we attended taught us to do it after the oil had warmed up. Cold, thick, gooey oil drains very slowly and much of it clings to the oil pan while the sediment lies in the bottom. Warm oil rushes out, carrying suspended crud with it. The biggest problem with draining hot oil is the risk of French-fried fingers.
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Bob Weber is an ASE-certified Master Automobile Technician. Send questions to Motormouth, 17717 Silcott Springs Rd., Purcellville, Va. 20132. Send e-mail with name and hometown to motormth1@aol.com. Answers are supplied only through the newspaper.
