Q & A #33 With The Auto Specialist
Q & A #33 With The Auto Specialist
Welcome back to the latest edition of the Auto Specialist. Lately, we’ve been covering a lot of great car questions involving nearly every part under the hood. From engines to transmissions to brakes and alternators, we’ve created an impressive library of automotive knowledge. I’d like to encourage you to write in with any car-related problems you’re experiencing so we can help diagnose them for you.
Last time, we helped a reader named Jonathan figure out what was causing the rotten egg smell in his car. We also helped Tony with his decision to buy a vehicle where the owner didn’t have the maintenance records. Today, we’ll help Tom with his Malibu’s head gasket and Doreen with her Cutlass’s fuel injectors. Let’s get started.
Question: I drive a 2000 Chevrolet Malibu with 112,700 miles. For the past six years, I’ve had to have the guys at my local garage take the head gasket out and put a new one in. I only drive about 14,000 miles every year and I know my car shouldn’t need a replacement this often (I read that online). It’s not a big deal because it’s just an annual thing, but it bugs me and it’s kind of expensive. Do you know why the head gasket in my car goes bad so quickly?
Answer: Thanks for writing, Tom. As you mentioned, replacing the gasket every year should be unnecessary. They typically last much longer. That being said, there are a lot of reasons why a gasket can fail. One of those reasons involves the surface of the engine block. Here’s what happens: the gasket’s job is to seal the area between your block and the cylinder head. A lot of times, the block’s surface is rough. That means the gasket can’t seal the area well. Coolant and compression leaks happen. Ask the mechanics at the garage to take a look at the surface of your engine block. I’m wagering that’s the problem.
Question: My car is a 1998 Oldsmobile Cutlass and the odometer says 157,247. When I press on the brake pedal, I can feel a pulsing sensation. I just had the brakes done recently, so they should be good, right? When I told the men who originally did the brake job about the problem, they couldn’t figure out the cause. Yesterday, I took my car to another repair shop in my area and asked them to take a look. They said my rotors have been trimmed too far and I need replacements. Honestly, I’m a little intimidated by mechanics. Can you tell me what they meant by the trimming?
Answer: Thanks for your email, Doreen. Here’s what the mechanics mean by trimming: when brake pads are replaced, the mechanic will sometimes “machine” the rotor if the pads are severely worn. Rotors can only be machined or “trimmed” so far. In fact, manufacturers will stamp the minimum right onto the part. If the rotor is trimmed below that minimum, the heat generated by your braking system will cause them to warp.
Your rotors are likely warped, which is why you’re feeling the pulsing sensation when you press down on your brake pedal. To the credit of the second group of mechanics, they’re right. You’ll need to have them replaced.
That’s a wrap for this installment. My thanks to both Tom and Doreen for allowing us to help them with their car problems. Next time, we’ll help Frank with his van’s fuel injectors and Jennifer with her car’s transmission. Be sure to come back for that. Until then, drive safely.
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Tags: Auto Specialist, Car Q & A
