vegascoug

So my wife was driving the rig, lost two of the three belts while she was driving. The A/C belt and the Power Steering belt were off, one was badly damaged and looks like it came off first, if I remember right it was the A/C belt.

So I repalced them all, everything worked except for the A/C. Checked the clutch and it spins okay, so it's not frozen, just won't engage.

Had my brother (GM Mech) take a look last weekend and he said it was low on freon, so we hooked it up and tried to add some freon. Without knowing how much to add, he was going to put 2 pounds in...but we didn't get that far. He vacuumed the system and then tried to add freon, but each time it fails around 1/4 to 1/3 pound. The high side gets up around 300-400 PSI and the system adding the freon shuts down because of an alarm that goes off.

However by putting in even that much freon, my A/C comes back on. Doesn't get "ice cold" as it used to, but it's working and is much better than nothing.

He thinks it could be a bad TXV (thermal expansive valve). He said they can be expensive and a major PITA because you have to take the dash apart to get to them, and when you take them apart you often break other parts that are connected to them.

His guess was that the system was "clogged" somehow and that's what lead him to look up the part...the TXV...I guess there's a little screen in there that can get clogged with tiny metal shavings and needs to be replaced. He's wondering (not knowing Yota's all that well) if that's why the system won't take any more than a QP of freon.

Any of you experts on here have any advice? Every time I come here someone shines the light directly on the problem, so I figured I try again.

I was afraid to use my A/C last weekend because I was 250 miles from home and was worried that the A/C was what locked up and dumped the freon (I guess there's a little release in the back that can blow if the high side gets too much pressure in it) and perhaps that's what threw the belts. I figured I'd try it when I got home where it's about 100 degrees every day. Haven't done it yet though.

Thanks in advance!

Mike

InternetRoadkill

Sounds like there's an obstruction somewhere. The expansion valve would be a good place to start. You could undo the a/c hoses that go to the evaporator at the firewall and blow some clean dry air thru it to see if it is blocked.

vegascoug

Okay, I'll try that

Without sounding TOO stupid, I am assuming there is an IN and an OUT so that if I blow air in one will come out the other? Is there a danger of too much pressure? I guess if it can handle 300 PSI in the system it can handle 120 PSI from my air compressor.

Are they hard to find? Or do I simply follow the two lines (High and Low) from where we put freon into the system.

Also, would I need to drain the system first? By removing hoses the freon would come out, right? Probably safest to vacuum the freon out first, drain it so to speak?

Mike

InternetRoadkill

Blow it in the little line (high side). It should come out the low side (big hose).

This is going to be a hard test to judge unless the line is completely blocked. Some restriction is normal for the EV.

The lines connect to the evaporator at the firewall. They should be easy to spot. You need to recover the freon before doing this. Also, the system will need to be vacuumed again before recharging. Depending on how long you leave the system open, you may need to replace the dryer as well.