Timing chain’s wear and tear
Q: Thank you for your column on automotive advice. I worked on cars when I was in my teen years, and I appreciate the details and common sense that you offer. Your column reinvigorated the discussions I had in the past about the timing setup for my 2005 Toyota Scion xb. It had a timing chain (like the triple primary drive chain on my Harley with metal links as I imagined it). Does it make any difference in wear and tear and longevity? — P.C., Chicago
A: The primary drive chain on your Harley is quite similar to the Scion timing chain. And the final drive belt on your bike is similar to a timing belt of rubber reinforced with tensile cords. There is no schedule for replacing the long-life chain so I would not do so unless doing an engine rebuild.
Q: I read your article about tire pressure dropping 1 psi for each 10 degree drop in ambient temperature and I agree. I have struggled with setting the tire pressure in summer vs. winter. If recommended “cold” tire pressure is 35 psi, then what is the proper pressure when it is 35 degrees out in the winter? Should you always set it to 35 psi regardless of the ambient temperature? — J.M., Rochester, New York
A: Your question apes that of many readers who are confounded by inflation pressure versus ambient temperature. Short answer: No matter the ambient temperature, inflate your tires to the pressure on the door sticker. Period.
Q: This is in response to your advice to R.P. of Nevada regarding the 2008 Toyota Solara tire pressure warning light. This reminded me of a similar situation l had with my mother’s 2011 Toyota Avalon. It turned out that Toyota had fitted the car with a full-size spare tire, which also included a sensor. I inflated the spare tire to specifications and the problem was solved. — R.S., Fitchburg, Massachusetts
A: Right you are. Because full-size spare tires are almost extinct, I blew it.
Q: I have a 1983 Mercedes 380SL that on rare occasions blows a dense whitish smoke from the exhaust. The car has a little over 80,000 miles on it. I have had several mechanics attempt to remedy the problem with no success. The car is stored during winters and only runs from April to November. This past summer absolutely no smoke for over 300 miles, then, last week, smoke. It usually happens when first started and driven. Also, it happens after the transmission seems to hang up shifting gears. The automatic transmission fluid is full. I’ve had the transmission modulator changed three
times using both aftermarket and genuine Mercedes parts. Each time the rubber in the modulator looks fine, but the problem continues. It only smokes for a couple of minutes and then stops. Any ideas as to cause and remedy? — D.G., Old Saybrook, Connecticut
A: As I began reading your question, my thoughts jumped to a problem with the transmission vacuum modulator. It is as if there is a tiny leak in the diaphragm allowing transmission fluid to seep into the housing. When you start the engine, it sucks the fluid in, burns it and emits smoke from the tailpipe. But there is another source for white smoke (steam): a bad head gasket. Keep an eye on your coolant level. If it drops and there are no obvious leaks, the gasket may be the culprit.
Bob Weber is a writer and mechanic who became an Ase-certified Master Automobile Technician in 1976. He maintains this status by seeking certification every five years. Weber’s work appears in professional trade magazines and other consumer publications.
His writing also appears in automotive trade publications, Consumer Guide and Consumers Digest. Send questions along with name and town to motormouth .tribune@gmail.com.