Q: You recently wrote that it's against the law for carmakers or dealers to require you to use their oil filter. Can you explain that more? I have a Subaru and have been purchasing their oil filters for my Forester.

R.S., Chicago

A: The Magnuson-Moss Warranty Act prohibits manufacturers from requiring consumers to use only their parts to prevent losing their warranties. Some service facilities mislead customers into believing that the dealer service departments must install only original equipment replacements. The Federal Trade Commission enforces the act.

Q: In your column on March 9 in the Minneapolis Star Tribune, you answered a question regarding oil usage in a Subaru Forester. Your answer said that one quart of oil every thousand miles is considered normal usage, with some engines doing better than others. My question: Is the thousand-mile rule true for blended oil? Synthetic oil?

A.P., Apple Valley, Minn.

A: If both oils are the same viscosity, there should be no difference in oil consumption.

Q: For the reader who complained about excessive oil consumption, Subaru issued TSB 02-157-14R, titled Surface Treatment Change to Oil Control Piston Rings, in which they indicate a course of action for correcting the oil consumption issue in several models with the 2.0-liter and 2.5-liter engines. Subaru's fix was to change the surface treatment of the oil control piston rings.

On affected vehicles, Subaru will replace the piston rings at no charge under the provisions of the car's warranty. On vehicles out of warranty, customers will have to pay for their vehicle's repairs, a major out-of-pocket expense, since the engine has to be disassembled, piston rings installed and the engine reassembled.

S.W., Chicago

A: I am so grateful when our readers report something that I missed.

Q: I am curious about something I read long ago and wonder if it still applies. When filling your tank with gas I read it is a waste of gas to continue to pump the handle once the auto shutoff has stopped the gas flow. I see people do it all the time to get to an even number, I guess. Does that extra you add just evaporate or is it actually going in the tank?

K.L., Bath, Pa.

A: Many of us used to top off the tank, rounding the price to an even number, sometimes to the nearest dollar. Many of us also used to use cash and this simplified paying. But it is not a good idea anymore.

Adding more fuel after the nozzle has clicked off may cause the emissions control evaporate canister to become saturated, leading to an expensive repair.

Q: It's that time of the year again. Please print the recipe for cleaning car windows.

G.A., Orland Park, Ill.

A: At the risk of sounding like Heloise, the ingredients are 1 cup of distilled water, 2 tablespoons of distilled white vinegar and 1 cup of isopropyl alcohol. Mix them up in a spray bottle. I also suggest using a microfiber cloth.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician.