850 AC not blowing cold after recharge

Messerschmitt101 · Post by **Messerschmitt101** » 05 Jul 2016, 19:51

Okay, so I have a 1996 850, and the AC is not blowing cold air.

I have tried charging the AC with some r134. Did everything there correctly.
Turned the car on, charged it till the pressure reached about 37psi (yes I did plug it into the low pressure valve). We had the AC running, while the recharge was happening.
However, when we feel the air coming out of the vents, it is hot. There was no cool air flowing through the system.

What have I done wrong? Not wait long enough? Or is there a bigger issue at play that I need to look at?

Best wishes.

Alex E.

Post by **tryingbe** » 05 Jul 2016, 20:01

Is the a/c compressor turning?

Post by **abscate** » 06 Jul 2016, 03:16

Are the supply lines to the evaporator ( up near the dash, in the engine compartment ) sweating humidity and feel cold ?

That will separate trouble with the AC hardware from a climate unit problem in the car.

You can't charge an AC correctly by pressure unless you know how to equilibrated tv and run the engine at 2000 rpm, those pressure gauges they sell are notoriously inaccurate.

Messerschmitt101 · Post by **Messerschmitt101** » 31 Jul 2016, 16:57

tryingbe wrote:Is the a/c compressor turning?

Yes, the compressor was turning.

And I will take a look at the Supply lines.

Apologies for the delay in replying.

Post by **Ozark Lee** » 31 Jul 2016, 17:31

Messerschmitt101 wrote:
tryingbe wrote:Is the a/c compressor turning?
Yes, the compressor was turning.

Are you absolutely certain? It is very difficult to see the center portion of the compressor turning inside of the clutch unless you know exactly what to look for and exactly the right angle to see it.

How much refrigerant did it take?

Did the pressure go up to 37 PSI and stay there or did it rise and then rapidly fall back again? What was the starting pressure?

...Lee

Post by **Botbasher** » 01 Aug 2016, 13:31

Did something similar on my daily driver a few years ago...

When you turn on the AC do you hear the tell-tale click of the compressor locking in and hear the engine bog down a little bit or does it simply keep idling?

+1 on the gauges being stupidly inaccurate!!

Did you turn the can upside down as some bottles tell you to do? This was my mistake and I ended up filling the system with oil and hydro-locking the compressor. Pressure was so high it tripped the high pressure cut-out and it couldn't re-balance itself.

Not an HVAC guy, but I know enough to fix things. I ended up getting a set of the HF HVAC gauges and one of the puncture type (not the built in hose kind) bottles of R-134. With the gauges, I was able to let it pump some of the oil off and into the bottle. After that I could see that my pressures were off and using the gauges I set it properly. That was 5 years ago and not a problem since. The compressor makes a little more noise than it used to, but then again, I was on a hot summer road trip when I did this and I drove a few hundred miles trying it every few minutes to see if I could get air just a few degrees cooler than ambient out of it. It was a miserable ride back home!!

Those gauges paid for themselves a couple times over right there and several times since. It's not really that hard to read and would suggest looking into them after you are sure the basics of the system (Clutch mainly) are working right.

Good luck and hope for cooler weather for you!!

K "chilling" S