S60 - Air Conditioner issues Topic is solved

[anon]

So I've got a 2004 S60 with about 94k on the clock now. I've read other postings about A/C issues, some of them I think said Volvo charges it at dealers from the high side? I wanted to get the right info for my issue, as summer is coming up and I'd like my A/C to work as well as possible.

Currently, while driving (or even idling) you can put your hand to the vent, even while it's on max, and feel it go from cold to hot, back and forth endlessly. Does this mean it needs to be charged up more? Should I bring it to the dealer and have the system professionally vacuumed/refilled? Other suggestions?

[oragex]

Does it do it when the Auto button is off?

On the heat control panel there is a small grid with three holes, don't put anything inside, just blow some air. It's the temp sensor and may get covered with dust.

[anon]

Appreciate the suggestion, will do it again but have done that only a couple of months ago. This was on an 80 degree day with the A/C temp set to coldest settings. Every few seconds it goes from hot to cold and back again. Doesn't quite seem right to me?

I'll also note that the car does eventually get to the set temperature, but takes longer than other cars I've had, and I can't say other cars such as my Ponitac and Volvo S70 had the A/C temp change rapidly in this fashion when set the same.

[JRL]

First use manual AC setting.
If it still goes from cold to hot to cold you have a different issue and needs to read with VIDA
If cold you do NOT need to add any R 134

If it's not the compressor clutch which I doubt at 80K miles there is something called the evaporator temp sensor which can go bad.
Again, read it with VIDA. If you don't... all you will be doing is replacing parts until the issue is found.
A new one will need to be initialized with VIDA anyway

[chrism]

I'm going to assume the compressor kicks on and off in correlation with the temp falling and rising?? A few things that can cause it to do that are low charge - easily checked at an A/C shop, condenser cooling fan isn't clicking on when it should - easily witnessed, or the evaporator sensor is faulty as JRL suggests.

FYI - the low pressure service port is hidden underneath the coolant expansion bottle and P/S reservoir. You'll have to lift either one or both of those components up out of the way to find the port.

If you suspect the evaporator sensor is goofy, you can take it out and test it with and ohm meter at a couple different temperatures. Jimmy57 that frequents this forum told me that a healthy sensor will read approximately 10K ohms +/- 200 at freezing and 3k ohms at 25C/77F. Also, the sensor is a very simple plug-n-play item, so it can be replaced without any Vida programming required. When my evaporator sensor failed it behaved the opposite of what you're experiencing. Mine would allow the compressor to run and run and run until the evaporator froze up and restricted the air flow out of the vents.

From what you describe, I would either suspect a low refrigerant charge or the condenser/radiator fan is working. One weird thing that can sometimes happen when the charge is just "sort of low" is that it will blow cool air out one side (let's say the drivers side for instance), and blow warm air out the other side.

Good luck.

[anon]

The one thing I can tell you here is that when it's warmer out (80+ for example) it seems to cycle more (from hot to cold). Today it was 74 and cloudy, I felt it and it stayed pretty consistently cold the entire time (much colder than outside).

I have cans of refrigerant with gauges on them, but what pressure level should I be looking for? I've never found a clear answer on that. I know it also varies with outside temp, if I've read correctly on other posts?

[chrism]

Ooops, I meant to say that maybe the radiator/condenser fan ISN'T clicking on when it should. Have you verified that it does function? Your cool weather vs hot weather scenario starts to make me think even more that may be the issue. You would think that in warmer weather the refrigerant would be running at a higher pressure and LESS likely to cycle the compressor if the problem was a borderline low charge. But what do I know?

When it's warm weather and the A/C starts to cycle frequently, what's the engine temp doing?

[anon]

Temp gauge on the dash is always stable/dead center no matter what (except when cold start, of course). I'll visually verify the fan function. If I'm correct, like my old Pontiac, they should stay on 100% of the time if the A/C is turned on at the controls in car?