Hello all, on my 92 D350 LE the ac is not getting cold. Cool but not cold. Any way with gauges on it the high side pressure was to high around 300psi and the low side was around 30 psi. So I was thinking something in the expansion valve. So I pulled the system down and replaced the expansion valve with new one. Pulled vaccum on the system and recharged. Ended up with the same thing. Any ideas on what the problem is?

Thanks
Mike

 

Condenser full of bugs and mud.

I've had "professionals" fuddle up heat pumps I've installed by missing that one.

 

I was gonna say poor airflo thru the condensor but JMartin beat me to it. Low side is right about where you want it but high side is a bit too high.

Sent from my SPH-L300 using Tapatalk 4 Beta

 

I was going to pull the grill out and check condenser and replace fan clutch next. Here is hoping that helps

Thanks again
Mike

 

You did not say what you recharged it with, R-134a can run this high and not cool well without a lot of airflow, check for a blocked condenser, or a slipping fan clutch.

 

Will try to get to the condenser and fan clutch this weekend. And yes was charged back with r143a. Is there anything better to charge one with other that the old r12?
And Jim what should the high side pressure be if all is well? And low side pressure be?

 

There's your problem. You put the refrigerant in backwards.

I charge old R12 systems with HC12.

 

What is the cost of the HC12 ? And where can I get it? Is it better than r134a?

 

HC stands for hydrocarbon. It's a 71/29 mixture of propane/isobutane.

If you make your own, 1 8 oz. can of IsoPro mountain stove fuel and 14 oz. of Coleman propane. (always dry) is about right for a single evap. system.

Here's a link to commercial product.

In my experience, it cools as well as R12 and doesn't leak as easy.

 

Thanks for the information, may give it a try

Thanks again
Mike