Q: The owner’s manual for my lawn tractor emphasizes that I use straight weight SAE 30 motor oil. Why can’t I use the same oil that I use in my cars? And, why is straight weight oil more expensive? — R.R., Round Hill, Va.
A: Air-cooled lawn mowers and tractors run much hotter than automobile engines. Cars run at a constant 195 degrees, but lawn equipment may go up to 250 degrees or higher. A single viscosity oil holds up better. Multi-viscosity oils generally start out with a low-viscosity base oil to which viscosity-index improvers (along with pour-point depressants) are added. Although you could use them in your tractor, Mike Barnett, a spokesman for Briggs & Stratton, advises against it unless the outside temperature is 40 degrees or lower. Using multi-viscosity oil in warmer temps may result in high oil consumption. Single-viscosity oil prices, he said, are a result of the supply and demand market factors. John Deere, on the other hand, advises using its Turf-Gard multi-viscosity oil (which meets automotive API SL and ILSAC GF-3 ratings) in all its engines.
Q: Every time I hear an ad by some oil company talking about how their additives clean up your intake valves, I think about certain auto companies bragging about their direct injection. The only problem is, all those additives don’t go through the intake valves anymore. I haven’t heard anybody talking about dealing with this problem. Have you? — F.K., Algonquin, Ill.
A: Nope, we have not. In fact, direct gasoline injection should result in clean valves for the life of the engine. With typical fuel injection systems, atomized gasoline is squirted into the air rushing down the tunnel of the intake manifold where that air picks up the fuel and carries it into the combustion chamber. Some of that fuel can collect on the backs of the intake valves where it builds up into sponge-like crud that causes driveability problems — particularly on a cold engine. With direct injection, the problem is solved.
Q: I have an Olds Cutlass with 40,000 miles and I want to use synthetic oil. I was told that if I do, I will have to use it all the time. Why? — S.V., Chicago
A: Whoever told you that is wrong. You can switch to synthetic oil and switch back any time you wish. In fact, you can even combine the two with no ill effects.
Q: I have a 2002 Chevy Impala. Sometimes the turn signals work and sometimes they don’t. I took it to a garage, but they could not find the problem. Should I take it to the dealer? When the signals don’t work I use hand signals. — S.Z., Windsor Locks, Conn.
A: The turn signals are integral with the hazard warning flasher module and we suspect this is the part that is going bad. It is not easy to get to, requiring removal of the steering column cover and the instrument cluster trim. Dealer technicians could be more savvy about this job than a general repair shop tech who may not have done one yet. We are frankly surprised that anyone today understands hand signals — other than the one made with a single, raised digit.
Q: We have a Chrysler Grand Voyager with 140,000 miles. We have a lifter or valve tap. My wife puts in STP or some other additive, but is there a cure? Our mechanic said that we should replace the engine. My neighbor said it’s not that bad and it could last a long time. We recently had a rebuilt transmission installed. — W.E., Coopersburg, Pa.
A: Without hearing the noise firsthand, and not knowing the van’s age, it is hard to advise you. If the interior and exterior are in good shape, you may want to keep driving the vehicle until the engine problem gets so bad that a rebuilt would be worthwhile. If that does not make economic sense, drive it until it dies.
Q: I bought a 2011 Ford Escape. How do you change the rear wiper blade, or clean under it? It does not lift up like the front ones. I have asked a Ford dealer and a few mechanics and no one seems to know. — R.R., Calumet City, Ill.
A: According to Ford’s published warranty information: “Where a vehicle has no factory-related defect, and is therefore not entitled to a warranty-related repair, replacement or adjustment, it is Ford policy nonetheless to provide certain maintenance items, when necessary, free of charge during a limited period….” It continues: “Wiper blade replacements will be provided during the first 12 months in service, regardless of miles driven.” We hope this helps until we have an opportunity to change one firsthand.
Bob Weber is an ASE-certified master automobile technician. Send questions to Motormouth, Rides, Chicago Tribune, 435 N. Michigan Ave., 5th Floor, Chicago, IL 60611, or email with name and town to motormouth.trib@verizon.net.
