Question — Each time I had my car's oil changed at the dealership, the dipstick showed that the oil level was a quarter of an inch to almost an inch above the "full" level. According to the owner's manual, over-filling could damage the engine. I called this to the mechanic's attention several times, and each time he insisted that the amount he put in was correct. He also claimed the extra oil would cause no damage. Finally, he checked his oil-dispensing gauge and found that — guess what? — it was not accurate, after all. He then proceeded to correct it. I still want to know if that previous overfilling could have caused any damage.— Will
TOM: It's unlikely, Will. It's true that overfilling the crankcase with oil can damage the engine. But in the vast majority of cars, you won't do any damage in the quantities we're talking about here.
RAY: A quarter of an inch on most dipsticks equals a quarter of a quart. And adding an extra quarter of a quart, or even half a quart, won't hurt anything.
TOM: When you overfill the crankcase by a quart or more, then you risk "foaming" the oil. If the oil level gets high enough, the spinning crankshaft can whip the oil up into a froth, like the stuff that sits on top of your cappuccino. And the problem with that is that the oil pump can't pump froth.
RAY: It's like trying to drink from a straw when there's not much left in the glass — what you get is mostly air. And air can't lubricate your engine.
TOM: Now, there are some cars that are more sensitive to overfilling than others. Volkswagens with four-cylinder engines come to mind. And if you had one of those, and the mechanic overfilled it by half a quart, I'd tell you to have him drain the oil and refill it more precisely. But unless your owner's manual specifically warns you — in dire language — not to overfill the oil, I wouldn't worry about it unless it's approaching a quart over.
RAY: And by the way, your dealership should be giving you free oil changes for life. If you led it to discover that it was giving away an extra quarter of a quart of oil with every oil change, think of all the money you're now saving the dealership on oil!
Question — Back in the 1980s, I drove a huge Chevy van. The steering wheel was so loose that I could turn corners using only a pinkie (of course, the steering wheel wobbled a little on straightaways, too). Now my wife has acute arm-muscle pain and needs a car with very easy steering. None of the new cars we've tested are easy to steer. If I want that same old-fashioned, easy steering, do I need to buy an old car? — David
RAY: You might. You're referring to the old GM power steering of the '70s and '80s. The "slosh" that they worked decades to perfect.
TOM: It's hard to find that now. These days, customers prefer to have a better feel for the road. So manufacturers have reduced the amount of steering boost they put in their cars. And you're right, almost all American cars now have more resistance in the steering wheel than they did 20 years ago.
RAY: So what to do? Well, first of all, you should really ask yourself — and answer honestly — whether your wife SHOULD be driving anymore. If she's got severe arm pain, will she be able to react and steer fast enough to get out of the way in an emergency? Will she put herself or other families in danger on the road because she can't swerve when necessary? If she has trouble steering an average, power-steering-equipped car, it might be time to give up the keys.
TOM: If you decide that she is well enough to handle emergencies as well as normal driving, then I'd look at the most traditional American cars you can find — cars like the Mercury Grand Marquis, the Ford Crown Victoria, the Lincoln Town Car and the Buick LeSabre. Those cars cater to older drivers, drivers who still like their seats wide and their steering soft.
RAY: If none of those does the trick, you certainly can look for an older used car. Or you can consider handicap controls. We have an area of our Web site dedicated to drivers with special needs. It's at the Car Talk section of www.cars.com. It's called the Special Needs Zone, and you'll find it in the "Got a Car?" area. Good luck, David.
The Magliozzi brothers' radio show, "Car Talk," can be heard Saturdays at 10 a.m. and Sundays at noon on KUER FM 90.1, and on KCPW 88.3/105.1 FM Saturdays at 9 a.m. and Sundays at 10 a.m. If you have a question about cars, write to Click and Clack Talk Cars c/o King Features Syndicate, 235 E. 45th St., New York, NY 10017. You can e-mail them by visiting the Car Talk section of the Web site www.cars.com.