Air con keeps dropping out

[Ewan]

Hi Folks,

I've got this annoying issue with the air con in my 98 D22 DX.
It blows cold for 15-20 mins then the cooling just drops out and starts blowing warm air.
Got it serviced and re-gassed and it didn't fix the problem, took it back a second time and the guy replaced a valve behind the dash which also didn't help. He was'nt very pleased when I told him the problem was still there and made some words to the effect that If I wanted it fixed he would have to have it in for some time to monitor it which would cost me a shit load of money.
Just wondering if this isnt a common problem that anyone has come across?

Any help is much appreciated, cheers

 

[reel-sensation]

Never had that problem with mine. Do they have a thermostat?

Alan

 

[Dion]

took it back a second time and the guy replaced a valve behind the dash which also didn't help. He was'nt very pleased when I told him the problem was still there and made some words to the effect that If I wanted it fixed he would have to have it in for some time to monitor it which would cost me a shit load of money.

He sounds like an arsehole, your first move should be to find a new HVAC tech.

Automotive AC systems are fairly simple.

To me it sounds like maybe your triple pressure switch is faulty, OR your thermo fan is not working.

Do you ever notice the electric thermo fan come on? It's loud above the engine sound. If you're not sure, run a little test. Put the AC on full, with the windows down (you're trying to create max load on the system). Then sit the truck idling for twenty five minutes or something. Or drive in thick traffic on a hot day. Anything that will minimise flow across the condensor. Feel free to block the front of the car off with a tarp or something. The fan should turn on audibly at some point. Come back to us with results

The reasoning is, the system has a triple pressure switch (behind the bumper) which, at an elevated condensor pressure, will activate the thermo fan. If the condensor pressure continues to rise then the switch will decouple the clutch in the compressor, turning off the system. When this occurs, the flow of cold air will turn to ambient temperature.

 

[Ewan]

Haha, Yeah more just a grumpy old man than an arsehole I think. The guy is about a thousand years old and I think he just cant be bothered anymore! Was convenient as he's in the same street as my work but I think I'm going to move on.

Will definitely give that a crack when I get a sec. There seems to be a manual switch for the thermo fan at the far right of the dash down low next to another identical switch which I'm yet to find a use for. Turning it off or on doesn't seem to make a difference.

I'll have a look and let you know

Thanks heaps!