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Three A/Cs died. Why?

My 2001 sable wagon had great a/c. Last summer, the car was overheating and we replaced an evaporator fan. Then the A/C went in early fall and we replaced the compressor. It was barely used before winter set in. Fast forward to spring. The new a/c failed after a few weeks work and, after failure, the car made a clicking noise (and smelled like burning plastic). The mechanic replaced the compressor under warranty, but we had to pay for a pressure relief valve. One week later, the a/c failed again – 180 miles from home – with same noise and smell. Also, the check engine light went on. I called my mechanic who said I could drive the car home, as long as I didn’t use the a/c. (It was 100 degrees out). When I got off the highway, the car was making an awful rattling noise. It is now at the mechanic, who said it is the compressor. Really? A brand new compressor? They said they replaced everything. Does anybody have any idea what in the car could ruin three compressors in less than a year?

There are many possible causes for the repeated failures and finding the cause will require hands on testing. Your mechanic sounds qualified and seems to be making every effort to take care of the problem since the system works well when he finishes and he honors the warranty. Certainly, he may have overlooked something in the previous repairs and he will likely make a great effort to cover every possibility this time. When looking through the Sable’s system I found that the high pressure switch is spec’d at 460psi and that seems extremely high. If the condenser fan is not operating perfectly the high side pressure will rise excessively when driving at low speeds or stopped and I would expect that something mechanical would fail long before high side pressure reached 460 psi. But of course, engineers who earn a great deal more than I ever have designed the system. Good luck on the current effort.

Did they flush the AC system prior to installing the new compressors? When compressors fail they can leave debris in the AC system. If this debris isn’t flushed out of the system it can eventually damage the new compressor.

Tester

Thanks, I’ll ask about both. When the second a/c failed, the mechanic said something about the pressure getting too high before the fan cycled on. Now, he mentioned something about the clutch failing not the whole compressor.

Did the mechanic replace the accumulator when he replaced the compressors? Did he add the correct amount of oil to the a/c system?

He now says it is the computer – that it is not remembering the settings and is causing the ac to work at too high a pressure. He wants me to replace that, but can’t be sure how long there has been a problem or whether the defective computer has damaged other aspects of the car. Time to junk it?

This is a far fetched diagnosis - I think the mechanic is grasping at straws with this idea. When a compressor goes bad it puts debris (pieces for metal) junk into the refrigerant that gets caught and collected on other AC components, mainly the evaporator. At this point a new compressor only is just going to fail again unless everything the compressor is connected to replaced as well. A new computer isn’t going to get rid of the debris in the rest of the system.

I think you need a new mechanic.

Thanks.

3 A/C compressors on your Sable. Do a Google search for “Ford A/C Black Death.”

BTW, the engine computer on your car has nothing to do with how hard the compressor works.