Q: I recently purchased a 2008 leftover new Toyota Tundra truck. It is an extra cab with a six-foot bed and four-wheel drive. Recently, I got a flat tire, so I put on the spare. To my surprise, the spare is a Bridgestone tire, while the other four tires on the truck are Michelin. I called the dealer to ask him if this was normal, and he said he checked the other trucks and they all have Bridgestone spare tires. Can you tell me if this is normal? Also, can you ask the manufacturer if this is common practice for a new truck?

A: I have seen this in the past with other vehicle manufacturers, especially if the “full size” spare is an option. Because most vehicle manufacturers use more than one tire supplier it is not surprising that the spare tire is a different brand. It is also not unusual to see four alloy wheels and a steel wheel as a spare. But just to be sure, I checked with Wade Hoyt, the public relations manager for Toyota. Wade checked with his truck guru and in his words, “this is common industry practice.”

Q: Most car owner’s manuals recommend frequent checks of the engine’s oil level, yet don’t state whether this should be done with a warm or cold engine. I check the oil in my car when the engine is cold in the morning, and it is always over the full mark. Does this mean that the tank is overfilled or does the engine oil level change when the engine is warm?

A: The engine oil in your car should be checked as recommended by the vehicle’s owner’s manual. In my car, for example, the manufacturer recommends warming up the engine, shutting it off and allowing it to cool for three to four minutes, then checking the oil. For most cars this is the typical procedure. The bottom line: Check the oil often—driving without sufficient oil will surely result in engine damage.

Q: I purchased a Nissan Altima in 2006. When I received the title, I noticed it was a salvaged title. I would have never purchased this car if I knew it was a totaled/stolen car. My problem is the “check engine light” keeps coming on. I have had the EGR valve cleaned and then replaced, and the engine de-carbonized twice, but the light still comes on. Now the mechanic decided the computer is a problem, giving false information and turning the light on. He feels that eventually the light will go off, because all the problems are repaired. The car runs OK; can you give me additional advice?

A: If your car was salvaged because of flood damage, you may be chasing this “check engine light” forever. Any wire that has any amount of corrosion and causing a poor connection could be causing the light to go on. I am a little concerned by your mechanic’s response that the computer will eventually straighten itself out. At this point, I would consider a second opinion with a technician that has the tools and knowledge to properly diagnose and repair your car.

Q: For the past six months, the battery in my 2004 Acura MDX has been dying for no apparent reason—never in my driveway, but always after I have driven somewhere and want to go home. One time, the battery died at a gas station: I turned my car off to get gas and then it would not start again. I took it back to the dealer and they said everything is fine. This is very frustrating—help!  

A: I am not aware of any particular starting problems with this model or its twin, the Honda Pilot. At this point, I would start with the basics: Testing the battery, all of the associated wiring, the ignition system as well as any anti-theft devices. 
 
Q: I have a 2005 9-3 Saab Linear, purchased new. In the winter of 2007, I had the front and rear brake pads replaced because the brakes squealed as loudly as a transit bus during cold weather. Despite replacing the brakes, they still squeal. Do I need to have the brakes replaced again? Is this a common problem with 2005 Saabs? I had a 1998 Saab 900 prior to this car and never experienced such a problem with the brakes. What should I do?
 
A: Brake noise is generally caused by the brake pads moving or vibrating very slightly. The brake pads and their associated hardware should be inspected. The second issue is that in the last decade or so, brake manufacturers have completely moved away from asbestos brake pads. Asbestos worked well as a brake component but has serious health implications. Since the switch to a safer material, brake noise has become more of a problem. At this point, I would return to the dealer and see if there is an alternative brake pad available.

Q: I have a 1998 Audi A4. This past month, I have had trouble filling it with gas. I can only get it to take about a quarter of a gallon of gas at a time before the pump sensor stops it as if it were full. It takes a very long time just to get a $20-worth of gas in the tank. What should I be looking for to fix this problem?

A: Look at the vent hose on the side of the fuel tank, as well as the “roll-over” or gravity valve. One or both of these could cause slow fueling.

Q: During the cold weather last year, the passenger side door stopped opening, along with the power windows on my 1990 Acura Integra. With the warmer weather, the windows work, but not the door. I cannot take the interior door panel off to fix the window because it is held on by screws accessible only when the door is open. Looking at the locking mechanism for the driver’s side door, I think the latch may be accessible by drilling a hole into side door panel. Do you have any other suggestions?

A: A locksmith may be able to manipulate the latch mechanism with a tool similar to those used to unlock a car with the keys locked in. The other option is a body shop, whose technicians run into these problems from time to time.

Q: Will stability control stop someone from swerving to avoid a child or accident?

A: Stability control and antilock brakes will help control a skid, but may not prevent a crash. Keep in mind Newton’s first law of physics: An object in motion will remain in motion unless acted upon by another force. Although these electronic advancements are very helpful and may get you out of trouble, you can’t overcome basic physics.