AC issues (Page 1/1)
Jeff LaFiero AUG 31, 12:10 PM
I've got a 87 GT V6 that has some AC issues. The high pressure switch on the back of the compressor keeps blowing off when I add freon to it.
Here's what I have done so far:
1. Cleaned orifice tube
2. Check for leaks(none found)
3. Checked for continuity on switches
4. Checked compressor. Clutch works and engages
5. Added oil, UV dye and Freon

The compressor keeps cycling on and off as I add freon to the system. The pressure goes between 20 and 50psi on low side. High side pressure is about 100psi. After about one can(12oz) of freon the high pressure switch (blue) blows out the back of the compressor.

My questions are:
1. Are the pressure switches in the right location on the compressor?(see picture below)
2. Is the hose to the compressor hooked up correctly?(not sure if muffler is the high side or low side on the hose)(it is hooked up directly above green pressure switch)
3. Could the condenser be clogged? If so, should the high pressure switch turn the compressor off?
4. Should the compressor keep cycling on and off?

Any help would be greatly appreciated
Thanks
RWDPLZ AUG 31, 01:43 PM
If the switch is blowing out of the compressor, it isn't fully seated, and the snap ring isn't in the groove, or snap ring is too small in diameter. If the pressure in the system is too high, the high pressure switch will turn the system off. If it got even higher, the blow-off switch would relieve pressure. 100psi is nothing as far as pressure in this system.

1. Doesn't matter, they can be in either cavity.
2. Yes, only goes on 1 way
3. Possible but unlikely. Most likely point of a clog is the orifice tube. High pressure switch should turn the system off if over-pressure, yes
4. yes, quickly at first (short cycling) as refrigerant is added, less and less as the system reaches capacity.
Jeff LaFiero AUG 31, 01:53 PM
Thanks RWDPLZ!

I'll try reseating them again to make sure there on properly.

Is there any way to figure out if condenser is clogged without removing it from the car?

[This message has been edited by Jeff LaFiero (edited 08-31-2021).]

RWDPLZ AUG 31, 02:42 PM
No, it has to be isolated from the rest of the system. If you pressurize one port, you should have flow through the other.
Shho13 AUG 31, 09:06 PM
Just for fun, take an air fitting off an air compressor, see if you can blow shop air through the system with no issues, orifice not installed ofc... If not, there's a clog. Isolate each component by unscrewing the nuts and fittings around the whole system to isolate.

If art flows through with no issues, it's probably along the lines of what RWD was saying!

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