AC Evaporator Replacement
Thread Starter
Drifting
Joined: Nov 2000
Posts: 1,390
Likes: 39
From: North Brunswick NJ
AC Evaporator Replacement
I read and enjoyed Mr Orange thread on AC, with lots of good information. I think my evaporator is leaking on my 72 sb, which is a very origianl car. It still holds a charge and works fairly well. I would like to know if anyone has replaced a evaporator and if they had any pictures, directions, warnings, comments on ease or difficutly, or any other comments on this refurbishmnt?
Ed
Ed
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
You say that the system holds a charge but then add that you think the evap is leaking. First be sure it's leaking and if it is, how much and how often are you adding refrigerant? It's a lot of work and expense to swap it out so if you're having to add one can every year or so, I'd leave it alone until it got worse. Assuming it's R12 refrigerant, there's still plenty available despite what many say. You can get all you want on Ebay for $25 or so a can. What every you do, don't add any stop leak products to your system.
Thread Starter
Drifting
Joined: Nov 2000
Posts: 1,390
Likes: 39
From: North Brunswick NJ
You say that the system holds a charge but then add that you think the evap is leaking. First be sure it's leaking and if it is, how much and how often are you adding refrigerant? It's a lot of work and expense to swap it out so if you're having to add one can every year or so, I'd leave it alone until it got worse. Assuming it's R12 refrigerant, there's still plenty available despite what many say. You can get all you want on Ebay for $25 or so a can. What every you do, don't add any stop leak products to your system.
Thanks for the response
Ed
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
The system is still 12. I am getting oil leaking from under the evaproator case. It had a charge when I put it up for the winter, not sure as of now. I will find out when weather breaks in the east. I am not sure how much work it is to replace. I dont want to do it until I am sure that it is the cause of the leaking refrig oil.
Thanks for the response
Ed
Thanks for the response
Ed
Last edited by Jud Chapin; Mar 2, 2015 at 12:12 PM.
Thread Starter
Drifting
Joined: Nov 2000
Posts: 1,390
Likes: 39
From: North Brunswick NJ
If you're getting oil dripping off the casing and it's clear in color, that's a good sign the evap is leaking. Just be sure the oil is not coming off the engine. If you don't have a leak detector, take it to a shop and have them check the system for leaks, including sticking the element down into the evap casing. If the refrigerant charge you had done was by a shop, they really should have checked for leaks prior to adding refrigerant. I believe that is Federal law now, but could be wrong.
Ed
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
The existing refrigerant has to be removed and should be recovered per federal law. Once the evaporator is replaced, the system should be checked for leaks, then pumped down into a vacuum for at least an hour and then charged with refrigerant and additional oil. A lot of shops cut down on pump down time as time is money. I generally pump mine down for several hours as you want to be sure all moisture is removed. Moisture is the enemy of a/c units as the combo of moisture and refrigerant attacks aluminum.
If you replace the evap, I'd suggest doing the same with the expansion and POA valves. Also the drier would need replacing. Do it right and you'll have many years of trouble free a/c.
Would u be doing the job? If so, I would get the GM service manual for your year for specific instructions. One thing I can tell you is don't force the casing back together. The new evap piping may not fit exactly into it. The pipes, or inlet/outlet, can be redirected a little. Make adjustments here rather then forcing the casing as it easily cracks. Ask me how I know.
Hope this helps. Jud
Thread Starter
Drifting
Joined: Nov 2000
Posts: 1,390
Likes: 39
From: North Brunswick NJ
I replaced my '76's and the biggest pita was the VIR. Yours doesn't have one so it shouldn't be as bad. I would guess it's a full days job for someone with a/c experience.
The existing refrigerant has to be removed and should be recovered per federal law. Once the evaporator is replaced, the system should be checked for leaks, then pumped down into a vacuum for at least an hour and then charged with refrigerant and additional oil. A lot of shops cut down on pump down time as time is money. I generally pump mine down for several hours as you want to be sure all moisture is removed. Moisture is the enemy of a/c units as the combo of moisture and refrigerant attacks aluminum.
If you replace the evap, I'd suggest doing the same with the expansion and POA valves. Also the drier would need replacing. Do it right and you'll have many years of trouble free a/c.
Would u be doing the job? If so, I would get the GM service manual for your year for specific instructions. One thing I can tell you is don't force the casing back together. The new evap piping may not fit exactly into it. The pipes, or inlet/outlet, can be redirected a little. Make adjustments here rather then forcing the casing as it easily cracks. Ask me how I know.
Hope this helps. Jud
The existing refrigerant has to be removed and should be recovered per federal law. Once the evaporator is replaced, the system should be checked for leaks, then pumped down into a vacuum for at least an hour and then charged with refrigerant and additional oil. A lot of shops cut down on pump down time as time is money. I generally pump mine down for several hours as you want to be sure all moisture is removed. Moisture is the enemy of a/c units as the combo of moisture and refrigerant attacks aluminum.
If you replace the evap, I'd suggest doing the same with the expansion and POA valves. Also the drier would need replacing. Do it right and you'll have many years of trouble free a/c.
Would u be doing the job? If so, I would get the GM service manual for your year for specific instructions. One thing I can tell you is don't force the casing back together. The new evap piping may not fit exactly into it. The pipes, or inlet/outlet, can be redirected a little. Make adjustments here rather then forcing the casing as it easily cracks. Ask me how I know.
Hope this helps. Jud
Ed
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
One related thing to check and what a lot of guys miss is the weatherstripping on the rear of the hood. This seals the engine compartment from the cabin keeping its hot air out of the duct work. Chances are yours is either missing or no longer functional.
Good luck with the job.
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