A/C troubleshooting
Thread Starter
Melting Slicks
Joined: Apr 2001
Posts: 2,119
Likes: 213
From: Pittsburgh PA
A/C troubleshooting
I'm looking at a 1981 corvette with inoperable A/C. Not sure what's wrong, but I believe everything is there. Let's assume the compressor is shot. What's the worst case scenario is dollars?
Thanks for your help!
Thanks for your help!
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Who's going to do the work? Best to have the system checked before purchase so you know what you are getting in to $ wise. I don't know what shops get today but I'd guess the worst case would be over $2K. Just the compressor would be considerably less.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
IF the compressor is dead, figure it pumped metal throughout the system. That means a full system flush, replacement of the accumulator and expansion orifice, and the compressor. Followed by pulling a vacuum on the system and recharging.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
As Tim states, an actual compressor failure involves the rings/pistons on the compressor failing, and polluting the entire system with metal particles. You'll need a $300 compressor in addition to the components Tim mentioned and the flush procedure.
However, it's not often that the compressor sees a complete failure like this. More often, when the "compressor fails," it's due to a leaky front shaft seal, clutch, or clutch/pulley bearing failure. You can apply power to the clutch with a jumper wire to see if it engages. Once engaged, and with the drive belt removed, you can turn the compressor over by hand to "feel" it out: If it turns smoothly with no roughness, chances are that the compressor itself is good, and you just need to replace bearings or clutch (or, you can replace the entire compressor assembly, less the system flush).
Keep in mind that any system leakage will cause the low pressure switch to open, preventing the clutch from engaging and "killing" the system. First step would be to do a good system leak check and see if the compressor kicks in with the system pressurized. If you're going to be doing a complete system work-over, you can leak check and troubleshoot by pressurizing the system with shop air.
Lars
Intermediate
Joined: Oct 2012
Posts: 48
Likes: 0
From: Grand Island Fl
You can do it.
Don't let AC stuff scare you. A rebuilt compressor, change everything to 134a, buy a few new parts.
The parts aren't that complicated, there's a pressure sensor and a temperature sensor. The dryer should always be replaced (this is the hardest part because of where it's located). If the condenser and evaporator aren't leaking, then it shouldn't be expensive.
I got mine going for maybe $300. This included new sensors, dryer, compressor and a new low pressure hose. I did buy an inexpensive vacuum pump and a set of gauges. If you look around you can still find some 134a for $4 to $5 a can.
The parts aren't that complicated, there's a pressure sensor and a temperature sensor. The dryer should always be replaced (this is the hardest part because of where it's located). If the condenser and evaporator aren't leaking, then it shouldn't be expensive.
I got mine going for maybe $300. This included new sensors, dryer, compressor and a new low pressure hose. I did buy an inexpensive vacuum pump and a set of gauges. If you look around you can still find some 134a for $4 to $5 a can.
