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Rebuild or Repair

bhaubold on Tue March 31, 2009 7:33 AM User is offline

Year: 1990
Make: Chevy
Model: K15-- Pickup
Engine Size: 5.7L

My 19 year old chevy pickup has stoped cooling. Compressor only comes on if the cycle switch is shorted. I'm assuming that the system has lost it's charge. Even with the switch shorted, there is no cooling. The question is: with 240,000 miles on the componets, do I repair or replace some componets? I was thinking a new compressor, dryer, expansion valve, and hoses. Having the evaporator and condenser check and starting over. Any comments?

GM Tech on Tue March 31, 2009 8:51 AM User is offline

Could be as easy as a leaky shaft seal-- most likely scenarion-- I replace shaft seals daily-- but you have to have special tools- all depends on how you want to attack the project- do some searches on this forum .. and you can make a better decision-- I would also encourage you to keep it R-12..... R4 compressors don't fair well with r134a...

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

bhaubold on Tue March 31, 2009 9:35 AM User is offline

I did notice alot of debris (oily dirt) around the clutch area. What type of special tools are we speaking of? Thanks for your reply, helps alot.

NickD on Tue March 31, 2009 10:45 AM User is offline

Tools to change the compressor seal, not very much, hub remover and installer, and the seal kit with an O'Ring pliers, and a plastic sleeve to keep the seal from getting cut by the keyway.

The compressor can be charged with 100 PSI of air and dropped in a bucket of water to check for leaks not different than a tire. Also a high pressure gauge can be installed in the outlet where you can hand turn the hub to see if you can hit a hundred or so PSI to learn it still can compress, should leak down very slowly or your check valves are shot. Should turn easily in full rotations with no binding, and no clicking sounds when rocking the shaft. A vacuum gauge at the inlet should show good vacuum when hand turning as well.

Condensers and evaporators can also be charged with air, but would take more like a bathtub to check for leaks, or to seal it off and watch for a pressure drop in the gauge. Condensers are not easy to clean which would be good reason to replace that.

With 240K miles on your vehicle, what about the rest of it? Ha, like an idiot, got the air working great in an 89 Continental but in a 40 mile trip, air suspension blew, forward clutch gave out, with head gasket leaks, about 7,000 bucks in repairs, the car was worthless, but the AC worked great.

bhaubold on Tue March 31, 2009 10:54 AM User is offline

NickD, thanks for the reply. The rest of the truck is in really great condition. After reading some of the replys and looking through this website for parts, I don't think it would be that expensive to replace the compressor, dryer, condenser, and maybe hoses. Should have a reliable system? Thanks again for your reply. What would you think it would cost to have a shop charge the system after I install all the new parts? I'm assuming that would be R-12.

GM Tech on Tue March 31, 2009 10:54 AM User is offline

Chick did a nice write-up ...here's his link

Shaft seal procedures

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

NickD on Tue March 31, 2009 11:14 AM User is offline

Well if it's an R-4, probably shot anyway, even though I cleaned and painted my kids, that thin steel case with that huge O-ring still rusted away, ironically, the seal was still good. He drove it another two years without AC, then got rid of it. Ha, when I was his age, didn't even want AC, wanted performance, AC is for old people, people like me.

bhaubold on Tue March 31, 2009 11:53 AM User is offline

What would be a fair price for a shop to charge the system? R-12

GM Tech on Tue March 31, 2009 1:28 PM User is offline

I seriously doubt you will find a shop that will deal with R-12-- I don'y know of any-- I do all my own work- and DIY will still charge with R-12.. Make a few calls- you might get lucky-- they will all tell you it will be just fine- done a ton of them that way.. whatever you want to hear- they'll tell you....

Every shop I know wants to convert them over- easier for them- and more money for them....

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

TRB on Tue March 31, 2009 1:39 PM User is offlineView users profile

We still work on R12 systems all the time. Matter of fact unless it is a complete compressor failure I suggest staying R12 on many vehicles. Works better for the designed system and repair can be more cost effective for the customer. Now a 250K R4 is on it's last leg and would suggest a new model over a shaft seal, but that's just my opinion.

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

NickD on Tue March 31, 2009 2:16 PM User is offline

LOL, when your leak detector goes nuts at the rear O'Ring seal and you cannot build up pressure by hand turning, it's no longer an opinion, it's a fact that your R-4 is toast.

bhaubold on Thu April 02, 2009 7:36 AM User is offline

The person that does the refrigeration where I work, asked me if R-409A would be compatable with my truck. Any ideas on this?

GM Tech on Thu April 02, 2009 9:13 AM User is offline

Run Forrest Run....away from that idea.....

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

bhaubold on Wed April 08, 2009 9:38 PM User is offline

I can't even say I'm an a/c novice. So, I have very little knowledge on the subject. The reason I asked about R-409A is that the people who work on the a/c systems and refrigeration in my building say they replace R-12 with R409a. Why is it so taboo?

Chick on Wed April 08, 2009 9:46 PM User is offlineView users profile

Your car uses rubber lines, commercial ac systems use hard lines which can use blends, cars can't. The opertaing pressure of R409A are close to that of R12, uses mineral oil, but won't stay in your system long and will kill it.. hope this helps.

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Matt L on Wed April 08, 2009 9:50 PM User is offline

If you're in the US, the EPA has some say in the matter. They do not approve of replacing R12 with R409a in mobile systems. Stationary systems are another story.

EPA rulings, no matter what you think of the science, do carry the force of law. And the penalties are quite steep.

bhaubold on Thu April 09, 2009 7:25 AM User is offline

I had no intentions of using the R-409A. I'm just wondering why. Thank you all for your help. Mostly because of the lack of equipment, it looks like I may be bringing my truck into a shop. If they find mutiple problems, I'll install new parts and have them charge the system. Thanks again.

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