Seizing car symptoms point to air conditioner

Dear Car Talk:

While driving on the freeway at about 70-75 mph with the air conditioner running in my 2006 Acura TL, all of a sudden, I heard this horrendous noise.

It sounded like my car was suddenly in too low a gear. The air conditioner stopped blowing cool air, although it was still running. This went on for about 30 minutes while I was just praying it wouldn’t break down on the way home.

All of a sudden, the car lurched forward. If I had been right behind somebody, I would have hit them. Once it did that, the noise stopped and the air conditioner started working again.

I took it to Acura, and they couldn’t find anything wrong and said to bring it back when it happens again. My regular mechanic didn’t find anything either.

Now it’s been almost a year, but I’ve been reluctant to take it out of town or in excess of 70 mph. I should note that nothing on my dashboard lit up as to any errors or engine issues.

It seems we’re all stumped, so I’m hoping you can help me out. I’m considering getting a new car just because I’m fearful of driving this car out of town. Any suggestions or advice?

— Debbie

I think your air conditioning compressor seized up, Debbie, or partially seized up. The clues all add up.

If your AC compressor suddenly seized up, or just became very hard to turn, it would no longer be able to compress your refrigerant. That means no cold air.

And if the belt was trying to turn the compressor pulley but couldn’t, the belt would slip, and that could account for the noise you heard.

Why hasn’t it happened regularly? I don’t know, but it’s possible that the problem occurs only when the compressor

gets really hot — like when you’re cranking the AC and driving at 75 mph for a long stretch.

I think selling the car — especially if you like it and it’s otherwise in good shape — is premature. Instead, ask your regular mechanic if he’d be willing to drive it for a few days. If he takes it out on the highway and can get the symptoms to recur, he’ll be able to confirm right away what it is.

And if he can’t make it happen, well, maybe he’ll make you a good offer on the car.

Or you can just go ahead and replace the AC compressor. That’s easily going to run you $1,000. But given the age of the car and your description of the symptoms, I think there’s a high likelihood that’ll solve the problem. And if you’re otherwise scared to drive the car, it may be worth the investment.

Do it now, before AC repair shops institute their midsummer “I’m desperate” surcharges.

Good luck, Debbie.

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