Intermittent A/C

Post by **Sveedy** » 21 Jun 2021, 16:02

Like I need this to start happening now. Had to drive down to Phoenix today, where it was a balmy 107*. Better than the 117* the other day but still. A/C worked fine for the two hour drive down, but on the way back up the " hill " I noticed the A/C cutting out. I could tell that the compressor wasn't kicking in. When I got back up to my turf, the A/C worked again. I checked the compressor gap and it was .35mm pretty much all the way around. A little tight in one spot and a little loose in another. Also checked the Freon and it was in the normal range. So if the compressor clutch is within spec, but it still cuts out, does that indicate a bad clutch ? New compressor ?
Sure is nice to be back home in A/C with a cold beer after today

Post by **Clemens** » 21 Jun 2021, 16:23

How did you check it was not low on freon? Don't you have to evacuate all freon and refill it properly?
I am also pretty sure that the AC has a protection circuit. In 107 degree weather I could imagine that happening.

Post by **misha** » 21 Jun 2021, 16:55

Yes....how did you checked freon level since you need a professional ac shop to do this?!

Other than low freon level....ecu will kill the ac compressor when engine temperature is high and cooling fan is working hard to maintain optimal engine temperature.
This would happen especially on hilly roads where high outside temperatures are pushing the engine to work harder than usual and cooling fan doesn't manage to keep the engine temperature in proper range.
That said...ecu kills the ac to minimise the load and to provide better cooling to the engine since ac condenser is adding additional heat when ac is on.

The other problem could be just a bad thermal switch on compressor.

Post by **Sveedy** » 21 Jun 2021, 17:17

What you guys have said makes sense.
And I checked the Freon by attaching a half full can and seeing how much, if any, Freon the system wanted. Basic but all I could come up with.

Post by **misha** » 21 Jun 2021, 17:42

In order to properly and fully recharge ac system....system must be evacuated first...then machine provides vacuum to the system for at least 30min and needs to drop to -1bar and to stay there.
When vacuuming is finished,then machine starts with filling the system with freon(r134a).
Cans of freon and how much the system will accept that way is not valid.

Ac will blow cold even when system is at 40-50% full but the compressor will cycle,it will cut in & out and makes all kind of problems.
High outside temperatures will also affect proper function of ac system if system is not properly(professionally)serviced because pressures on high and low side will not be in spec.