Gregski,

On VERY hot days the compressor would lock up, twice the High Pressure Relief Valve on the compressor blew the freon out....the sound of a jet engine roar, and a cloud of white vapor billowing from under the hood. Now that says something because the blow off pressure is something like 538 psi!

The dealer replaced the pressostat and freon to the labels on the sticker under the hood, but it happened again.

When it happened a second time, it was 2,000 miles out of warranty and Volvo wouln'd commit to repairing it again for free, even though they never really 'repaired' it the first time.

So I bought the green book and did the research myself. It turns out that the freon sticker on my car said that it was an 'executive car with rear a/c'. The amount of freon listed was 1 lb, more than a standard S90!

So I beleive my car was overfilled at the factory, and then again at the dealership by someone who just read the amount listed on the Volvo sticker. But... this did not explain why the High Pressure cut-off did not shut the compressor off before it locked up or the blow off valve popped. It had to be a bad high pressure cut-off sensor (on the condensor).

So I replaced the High Pressure cut-off sensor, the pressostat (which was toast again), the accumulator and put in a smart Variable orific valve and had the shop igonore the Volvo freon sticker and put in the correct amount which was 1 lb less. It's now been working flawlessly for the last 2.5 years.

DEWFPO
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1998 S90 068,300 and 1995 964 152,300