I installed a new compressor. Old one had a bad seal, it didnt contaminate the system, so i doubt I have a blockage. I have a newer accumulator, oriface tube, and condensor. I got it vac'd, and recharged. It cools great when going down the road. But at idle, it wont cool, and when I have the gauges on it, it will run the high side to over 400, then I turn it off for fear of ruining something. Not sure how high it will go.
I replaced the Hi pressure switch to rule it out, no change.
Could I have a bad fan clutch, that is not pulling a enough air?
The fan clutch was replace last fall and never used AC last fall to see if there was a difference.
Thinking about going with some flex-a-lite fans and wire it into the AC
Need some help, its getting hot.

 

Orifice tube. The most likely culprit.

Chris

 

Is it stopped up? is that what your thinking.

 

Stopped up or close to it. I haven't seen the low side pressure so it's hard to tell. If the low side is near zero or pulling a vacuum when the high side is pushing 400, that orifice tub is the very most likely point for the blockage.
What's the low side doing?

Chris

 

I think it was around 40. I wasn't really watching it, cause the hi pressure was going so high.

 

Yep. Doesn't take too big of a piece of something to stop it up.

 

I was told that the High Pressure cut out is around 425.
Is that right?

 

Make sure the condensor and radiator is clean!!! Lack of air flow through the condensor area will cause hi heat and hi pressures. Prob a blockage though. Hope no one put stop leak in it.....

 

Stop leak, GM put out a bulletin warning against it saying that it could block the evaporator, because that's what it does, block tiny passages. You said you changed out the orifice correct? Was it the right one? Did you put it in the right way? I've worked on them at the Caddy shack and a person comes in complaining about a problem and they just had it fixed at Joe's garage. Unfortunately Joe put the orifice in backwards.

Also I don't know what type of failure your compressor had, you said leak? Your old orifice was it full of junk? The GM compressors would grenade and we would replace the orifice with the compressor and sometimes add an inline filter to catch anything before the orifice. If we did not add a filter sometimes the system would burp a pile and block the orifice and then ac would quit working minutes after you just fixed it. Run your hands around the lines, check the high side from the compressor towards the orifice for temperature variations, it should be hot until the orifice then it will go to cool. Check where it runs into the condensor and out as well, a good laser temp gun works good for this but just putting a hand on it help. If your running your hand along and it suddenly gets cool and it's before the orifice there is a problem, the clog is acting as an orifice.

One of our add on filters got clogged up, the car had a catastrophic failure, like a grenade went off. All new parts intalled, started car and ac on, worked for 1 minute then quit. The lines were hot up til the add on filter, then the went cold to the orifice where it did something else. The refrigerant should not change until it hits the orifice, this add on filter was so clogged it acted as an orifice. Took three $80 filters to get that car where it would run and then they came back a week later for another filter, that took care of it. They said doing it that way was cheaper than replacing all of the components.

You could put a fan, box fan, house fan in front of the condensor while you test it in your driveway and see what that does to the high side pressures. It's sounds like an airflow problem but without driving down the road with your guages taped to your window to see what they are like it's hard to say.....and yes, that has been done before, as well as fuel pressure guages and vacuum guages....

Shawn

 

I forgot all about this. Start right here. The puke bottle in known to clog radiators. It may even look clean on the front but when you separate them, they'll be a circle of goop and grime from the wet oil getting into them. This would definitely cause this issue.

 

Look here at these pics:

https://www.dieseltruckresource.com/...ogged+radiator

 

If both high and low sides are high, it usually indicates an air flow problem or overcharge. I replaced the fan clutch on my Chevy w/Cummins back in December. Once the temps got high enough this spring to need a/c, it would not cool at idle and popped the pressure relief on the compressor. Did some investigating and they sold me a fan clutch for a non-intercooled truck. Whether that was the problem or the new clutch was bad I don't know but a new clutch for an intercooled truck fixed the problem.

 

I dont have a puke bottle, its a 12 valve.
I did check for air flow blockage, no problems seen.
Im thinking it is the fan clutch, I bought it at Oreillys Auto. it seems to free wheel a lot. but it does keep the truck cool.
Im going to try the box fan trick tomorrow.
If that is the problem, i am debating on weather to go to OEM fan clutch, or leave the Oreilly fan clutch and run one electric fan to help AC or to get rid of belt driven fan all to gether and go with a dual electric Flex a Lite setup?