Ray Magliozzi

Ray Magliozzi

DEAR CAR TALK: I have a love-hate relationship with my 2015 Subaru Outback.

Driving from Michigan to Yellowstone National Park, it made a rhythmic noise that increased with speed all the way there and back. It made my wife and I very uncomfortable and nervous.

Upon our return, the dealership discovered we had defective wheel bearings in both front wheels. I heard the mechanic say something about so much heat buildup that parts were welded together.

New parts were installed, and a fairly quiet ride resumed.

But I worry about every little noise the car makes now. Could the damage caused by the heat buildup back then affect the car’s performance three years later? Welded parts sounds so bad. I wonder if all I got was a Band-Aid fix. — Tim

DEAR TIM: No, you’re fine, Tim. Although you might consider meditation for the Outback anxiety you’ve developed.

The parts that were defective were your wheel bearings. The wheel bearings attach the axles to the wheels, while allowing the wheels to spin. They’re made of two cages with a bunch of ball bearings in them, and the balls are what allow the wheels to spin easily while the bearings support the weight of the car.

If a bearing fails — due to poor manufacturing, mileage or lack of lubrication — it becomes harder to turn, and it gets hotter because of the friction. That’s what happened in your car. That’s why you were hearing that rhythmic noise all the way to Yellowstone and back. You’re a patient guy, Tim.

But here’s the good news: A wheel bearing is a completely self-contained unit. Even if it heated up and fried its ball bearings to the point that some of them fused together, nothing else around the wheel bearing would be harmed. Once the bearing was replaced, your car was absolutely fixed, and there’s nothing further to worry about.

I’d take them at their word that the original wheel bearings were defective, Tim. They’re gone now. Nothing to worry about. Enjoy your car.

DEAR CAR TALK: I have a 2017 VW Golf that I purchased used. It had 8,000 miles on it.

I noticed one of the tires did not match the others. I figured it had been replaced because of damage. After about six weeks of use, I got a low tire pressure warning. Sure enough, the odd tire was the one that was low.

I had winter tires on for five months. The odd tire did not lose any air while it was stored. I switched back to my summer tires and sure enough, after about six weeks, I got a low tire pressure warning again — same tire.

The tire has been checked for leaks; none can be found. It appears to only leak when driving. It has been removed from the wheel and remounted, same results.

Any suggestions? — Roger

DEAR ROGER: It’s not unusual for a tire to only lose air when it’s being driven. When the tire is just sitting in the garage on its rim, off the car, it’s not being deformed. It’s not being subject to all the forces tires are under when the car is stopping, turning and going over bumps.

At some point, when that tire is deformed in a certain way, it’s slowly losing air. Now, there’s a very small chance that the wheel is at fault. If the tire had to be replaced due to damage, it’s possible that damage was from a huge pothole that also bent the rim.

Perhaps the previous owner had the rim straightened, but there’s still a slight irregularity. I trust your mechanic — having dismounted and remounted the tire — would have seen anything obvious. And the car is too new to have rust or corrosion around the wheel.

You can test the “wheel” theory by moving the suspect tire to another wheel. Swap a couple of tires to different wheels and then see if the leaky tire still leaks. By process of elimination (let’s see ... you have the wheel and you have the tire), you can confidently conclude that it’s a bad tire.

I’m pretty sure that’s what it is, Roger. If it were my car, I’d skip the further experimentation and just invest $110 in one new tire. I think that’ll fix it.

In the unlikely event that the leak continues on the new tire, bring a friend to hand you tissues to cry into when you go to price a replacement wheel at VW.

Got a question about cars? Write to Ray Magliozzi in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.

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