Dayton Daily News

Q I'm considering replacement tires. Presently my car has the original equipment tires that were installed at the factory. They are Michelin MXV P195/65R15 tires. It's my understanding that the car manufacturer and the tire manufacturer matched the tires to my car.

In my search for new tires, I have found tires of the same size that are less expensive than the tires on the car. Is it ok for me to have a different brand of tire of the same size installed? E.W., E-mail.

A This is such a great country. There are so many choices available that meet or exceed car manufacturer specifications that you should not have any trouble finding a set of tires for less money.

As long as the new tires equal the present tires that are on the car, you should not notice any difference in performance. Actually, new tires should respond better than the old tires after a few hundred miles .

Experienced technician will find cause

Q I own a 1990 Ford Ranger with 130,000 miles. I've owned it since it was new. It runs great and has been well maintained all of these years. But lately in the morning, it is difficult to start.

I talked this problem over with a mechanic friend who suggested that the electric fuel pump in the fuel tank probably is the failing. He suggested that I turn the key on for a few seconds before starting the engine.

I followed his advice and the engine starts right up. Then the truck starts without fault the rest of the day. I've been doing this for a while but now I have to turn the key on and off a few times. Will a technician with the proper equipment be able to determine if the fuel pump is the source of hard starts? C.I., E-mail.

A Yes indeed, an experienced technician with the proper diagnostic tools can determine if the fuel pump is the cause of the trouble.

It's possible that the pump is worn and does not deliver the volume of fuel the engine needs. A technician can check the fuel pressure and volume but he will need to do this at the start of the day.

There also is a lot more to starting the engine than you may think. There is a fuel pressure regulator, fuel pressure regulator solenoid, engine control module, fuel pump relay, air flow sensor and more that all need to be working properly. A technician should perform tests to make sure these items are working correctly. However, from what you describe it's likely the fuel pump is the cause of your concern.

Q My 2006 Pontiac Grand Prix with a 5.3 liter V-8 uses too much oil. I purchased the car when it had 6,000 miles on it. Now it has 15,000 miles. I have changed the oil every 3,000 miles. The engine hasn't used any oil in between oil changes.

Recently I switched to synthetic oil. After driving 1,700 miles, I noticed that the oil was low about half a quart. I topped it off to the full mark. After driving another 350 miles, I checked the oil level. It was down one half quart again.

Was it a bad idea to switch to synthetic oil? How often do you recommend that I change the oil now that I'm using synthetic? B.C., E-mail.

A According to General Motors, it is acceptable for the engine to consume a quart of oil every 2,000 miles. Oil consumption may vary depending upon driving habits. If you tow a trailer or drive aggressively, oil consumption may increase.

Switching from mineral oil to synthetic lubricant may have an effect on oil consumption, but generally it doesn't.

In your case, oil consumption seems to have increased. Perhaps the valve seals are leaking oil into the cylinders. If so, replacement is the cure.

As for how often you should change the synthetic oil and oil filter, every 3,000 miles or three months, whichever occurs first.