[DMCForum] Re: AC Went "POOF!"

["content22207" <brobertson@xxxxxxxxxxxx>]

Does your car have the high pressure cutoff switch? (I think this was
added to later production). A/C cycling is controlled by low pressure,
not high.

If you're missing that switch (or if it fails to activate properly),
and something like ice on the low side obstructs freon flow, you may
have built up too much pressure on the high side. My system has a pop
off valve next to the accumulator for just such emergencies -- perhaps
that was added later too.

A/C hoses are sealed to the compressor with O Rings (recessed into the
compressor back but flat against the hose manifolds). Same seal
arrangement as intake manifold to the heads. If the compressor is
allowed to keep pumping the high side when it should have been cut
off, those O rings could be the weakest point of failure.

Bill Robertson
#5939

>--- In DMCForum@xxxxxxxxxxxxxxx, "Videobob Moseley" <videobob@xxxx>
wrote:
> I was driving my car to a local car show yesterday, I hadn't driven
it for 
> about a week,
> it was about 100F and I had the AC pumping full.
> I was sitting at a stop sign about a block away from my house,
> (the car had been running only a few minutes)
> and there was this loud discharge from the engine, like something 
> pressurized
> had popped, I could see a spray of smoke in the rear view mirror
coming from
> under the engine lid.
> I quickly turned the car off.
> The car was not over heating, or had even warmed up yet.
> I guessed that I had blown a water hose, but there was no water!
> No oil, no grease, or no sign that any thing was discharged.
> There were no holes, busted hoses or anything visibly wrong.
> 
> I cranked the car back up and it started and ran just fine....
> ...except no AC!
> The fan was going but the compressor would not kick in.
> So I must assume that the explosion was my R12 shooting into space.
> The problem is, I can not figure out from where, or why?
> 
> Does anyone here know what happened and what I need to do to fix it?
> Should I take it to a Volvo dealer, or someone that deals with older
Euro 
> cars
> and what parts should I refer to as far as compressors and hoses?
> Is this standard stuff they will recognize?
> 
> Thanks for the help.
> - Videobob

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