Question: My 1985 Ford Thunderbird was delivered with a spotted windshield. It looked like simple dust or dirt spots that would wash off. I've tried Windex, Glass Wax, ammonia and newsprint to no avail. Can you recommend a product? The Ford dealer is not helpful.--S.B.M.
Answer: You have tried most of the common glass cleaners, so we can assume your spots were deposited on the windshield by some unusual liquid solution that will not be dissolved by ammonia, the most common ingredient in glass cleaners.
It sounds as though the spots are clear and not a thick film, such as a sap or lacquer. If they are a thick filmy substance, you might try to gently scrape them off with a single-edge razor blade.
Otherwise, your best bet is a little experimentation and a lot of elbow action. I suggest trying to rub them out with a cloth soaked with white vinegar or lemon juice. The weak acid in those liquids could help dissolve an alkali deposit. You might also try such things as alcohol or paint thinner. Be careful not to let any of these get on the paint since they may damage it.
If all this fails, find a professional glass shop. The spots can probably be rubbed out with glass rouge, a polishing substance that is not usually sold at retail stores. In any case, don't use any abrasive cleaners because you will certainly scratch the glass and probably ruin the window.
Q: I purchased a Nissan pickup with a standard four-cylinder engine. It now has 1,200 miles on it. Lately, while starting it in the morning, I hear a pronounced bearing slap when it first starts. It lasts one or two seconds. The local Nissan dealer said it is normal, but a bearing slap on a brand-new engine worries me. What causes it?--G.L.
A: The bearing slap on the Nissan engine is a known problem. The company is confident that the bearing slap will not reduce engine life, and it has found no damage in high-mileage engines. Nonetheless, Nissan is working on a fix.
The noise is created by a lack of oil in the crankshaft bearings in the initial seconds after the engine is started. The deficit of oil is caused by oil draining out of the oil passages inside the crankcase and then down to the oil pan.
The noise subsides once the oil pump delivers oil to the crankshaft bearings. But in the few moments without oil, the slapping noise you hear is metal against metal without proper lubrication.
You might be able to help eliminate part of it by using an original-equipment oil filter, but this is of limited benefit because the oil does not drain down through the filter. Nissan is looking at installing a check valve that will lock oil into the crankshaft when the engine is shut off.
Q: Is it OK to use dish-washing soap to wash your car? I usually use water, but sometimes it's hard to remove dirt or grease. Doesn't soap take some of the wax off?--P.R.O.
A: Dish-washing soap is a fairly mild soap and should remove far less wax than a laundry detergent. Of course, water will remove the least wax, but not using any soap has its drawbacks. On a filthy car, dirt will become embedded in the cloth or sponge and you risk scratching the paint.
Car soaps sold in auto-supply stores have emollients that are designed to dissolve grease and other common road grime, but they aren't nearly as inexpensive as dish soap.
Ralph Vartabedian cannot answer mail personally but will respond in this column to automotive questions of general interest. Do not telephone. Write to Your Wheels, You section, The Times, Times Mirror Square, Los Angeles 90053.