AC stops working after 10-15 minutes - Volvo, S70 SE, year 2000

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Bob135 - 31 May 2006 21:12 GMT

Hi,

I have a problem with the Air Conditioning in my Volvo. After 10-15
minutes of working just fine it stops working and it will blow only air at
the outside temperature. If I shut down the engine for a while the air
conditioning will start working again for another 10-15 minutes.
The 10-15 minutes that is working the Air Condition is working properly
and is cooling very well.

I had the car cheked air Conditioning freon and presure and the guy told
me that there is no problem with AC so they have to check the electrical
system.

Can anybody tell me what is the possible problem with the AC?

Please advice!

Thanks

Bob

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Mike F - 01 Jun 2006 13:31 GMT

> Hi,
>
[quoted text clipped - 16 lines]
>
> Bob

There are 2 common causes of the A/C working fine for a while -
typically 30 minutes - then cuts out and doesn't work until the car has
cooled off.

One is a superheat switch that turns the compressor off when it gets too
hot. This switch is on the backside of the compressor. You need to
join the 2 wires going into it together. The best way is to follow both
wires to a connection about 6" (15 cm) away, disconnect the superheat
switch wires and connect the 2 other wires together. (The connectors
will just plug into each other.) Do not remove the superheat switch, as
the refrigerant will come blasting out. Note that the design idea of
the superheat switch was to save the compressor from overheating, its
setting is too low, causing the compressor to turn off when there's
really no problem.

The other cause is that the gap in the compressor clutch being too
large, and the magnetic force is not strong enough to engage the
clutch. (Removing the superheat switch from the circuit as described
above will help this problem, as it will increase the voltage available
to the clutch a small amount.) Others have used the wire going to the
clutch to engage a relay that is fed power directly from the battery.

Signature

Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

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Eric - 01 Jun 2006 17:09 GMT

Hi,
I've got the other problem with my AC. My clutch doesn't engage. I'll try
the fix this weekend and post an update

Thanks

Eric

>> Hi,
>>
[quoted text clipped - 39 lines]
> to the clutch a small amount.) Others have used the wire going to the
> clutch to engage a relay that is fed power directly from the battery.

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Bill - 01 Jun 2006 13:43 GMT

I had the very same problem this week with my 98 V70. Took it to the
shop and they sucked out the freon and found it significantly low. They
recharged with the right amount of freon and added a leak detector dye.
The system has been working perfectly since then.

Bill

> Hi,
>
[quoted text clipped - 16 lines]
>
> Bob

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