'99 V70 AC Problem

Post by **Rob3** » 10 Jun 2007, 22:40

This seems to be somewhat common, yet I haven't seen a solution.

AC works fine until outside temp approaches 90

Post by **Ozark Lee** » 11 Jun 2007, 10:31

The compressor has a thermal sensor that will turn it of if it decides the compressor is overheating. My understanding is that the condition is exacerbated by an improperly shimmed A/C clutch.

There was a good thread on the subject over on VS that includes a good writeup on re-shimming the compressor.

http://volvospeed.com/vs_forum/Ac-Therm ... 76833.html

...Lee

Post by **Rob3** » 11 Jun 2007, 20:21

Thank you! That was excellent.

Does anyone know what temp the switch is supposed to open at?

My thought is to replace the "bad" one with a good one (of a completely different type) and mount it on the Compressor, somehow.

cyclmck · Post by **cyclmck** » 11 Jun 2007, 20:40

Check to see if the fan is coming on, that would explain why the a/c works when moving but not at a standstill (no airflow through the condenser means no heat exchange)

Post by **Rob3** » 11 Jun 2007, 21:12

The Fans all seem to be working fine. Engine temp is fairly constant, too.

The only thing that seems to matter is outside temperature. Below 85

Post by **matthew1** » 11 Jun 2007, 22:38

Collapsing hose?

Post by **Rob3** » 12 Jun 2007, 21:20

Thanks for the info.

I hope to get a look at this in a couple of weeks. I'll remember to look for this, as well as the Compressor Clutch Gap and the Thermal Cutout Switch.

Thanks again for everything, including the reply.

Rob3

TheDrivenMan · Post by **TheDrivenMan** » 02 Jul 2007, 08:19

I'm having the same issues with my '95 850

Ice cold a/c for a while, then nothing; turn off the a/c and wait a few minutes and it is cold again.

The cooler it is outside, the longer the a/c will function normally. If I'm in slow traffic on a very hot day, the a/c fails too cool at all.

Plenty of line pressure

R

Post by **Rob3** » 03 Jul 2007, 05:52

Sorry. I haven't tried to fix this yet. I've so many other things going on and the cool lasts from home to work and back, so I haven't been trying too hard to find extra time. I know it needs to be done...

Post by **Rob3** » 15 Jul 2007, 15:02

Just FYI:

I removed the Relay that Operates the Compressor. I disassembled it and looked at it. The Relay showed signs of heat, but it showed a Reliable Connection with my Meter. I operated the Relay several times and each time the Connection was reliable.

I placed a 12 Volt Lamp across the Relay Coil and inserted the Relay back into the car. I routed the wires from the Lamp so that I could position the Lamp near my Wipers. In this way, I can see if the Compressor is being told to turn On while I'm driving down the road.

Since then, the AC System has not failed. It has been a couple of weeks, so far. I don't know if it has to do with the Relay, or if it is just coincidence.

If things change, I'll let you know.

BTW, the Relay is in the Triangular Box nearest the Battery, with the Large Fuses. It is the narrow Relay which is closest to the Engine.

Rob3