Change a/c evaporator how difficult?
Thread Starter
Melting Slicks
Joined: Feb 2008
Posts: 3,412
Likes: 118
Change a/c evaporator how difficult?
I just put $1200 in my a/c rebuild which was everything but the evaporator. I wanted it working before my car went to the body shop for paint. I got that task done and then the car set for two weeks in the garage. Saturday I took it to the body shop and the AC would not work and the whole inside of the windows were completely fogged up. So anyhow I'm pretty sure the evaporator is going to need replaced. I hate the idea of someone leaning over my newly painted fenders to replace the evaporator. it will be four to six weeks before I get the car back from paint so I need to figure out rather to tackle the job on my own or have a shop do it. So how difficult is it and does it involve getting under the dash from the interior?
Le Mans Master
Joined: Nov 2016
Posts: 9,261
Likes: 951
From: Lake Tahoe, CA
I just put $1200 in my a/c rebuild which was everything but the evaporator. I wanted it working before my car went to the body shop for paint. I got that task done and then the car set for two weeks in the garage. Saturday I took it to the body shop and the AC would not work and the whole inside of the windows were completely fogged up. So anyhow I'm pretty sure the evaporator is going to need replaced. I hate the idea of someone leaning over my newly painted fenders to replace the evaporator. it will be four to six weeks before I get the car back from paint so I need to figure out rather to tackle the job on my own or have a shop do it. So how difficult is it and does it involve getting under the dash from the interior?
The evaporator is accessed from the engine bay and from under the car.
As for ease ? Depends on your skill level and patience.
Best.
Last edited by caskiguy; Jan 6, 2019 at 10:19 PM. Reason: add content
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
I just put $1200 in my a/c rebuild which was everything but the evaporator. I wanted it working before my car went to the body shop for paint. I got that task done and then the car set for two weeks in the garage. Saturday I took it to the body shop and the AC would not work and the whole inside of the windows were completely fogged up. So anyhow I'm pretty sure the evaporator is going to need replaced. I hate the idea of someone leaning over my newly painted fenders to replace the evaporator. it will be four to six weeks before I get the car back from paint so I need to figure out rather to tackle the job on my own or have a shop do it. So how difficult is it and does it involve getting under the dash from the interior?
Racer
Joined: Aug 2018
Posts: 266
Likes: 52
I think the evap is accessed under the hood.
Ive done a fair amount of ac work but never on c3 vette.
I think all GM’s for decades had evap accessible in the black box under the hood. I know the have a fixed orifice simple control system. Your guess that the evap is leaking seems right based on the story. Maybe add dye. Charge it with cheap 134a until you find the leak then use expensive rare r12 once the leaks are gone.
Ive done a fair amount of ac work but never on c3 vette.
I think all GM’s for decades had evap accessible in the black box under the hood. I know the have a fixed orifice simple control system. Your guess that the evap is leaking seems right based on the story. Maybe add dye. Charge it with cheap 134a until you find the leak then use expensive rare r12 once the leaks are gone.
Thread Starter
Melting Slicks
Joined: Feb 2008
Posts: 3,412
Likes: 118
It is a 1975 so obviously a small block. Since the whole thing can be done from under the hood I will most likely do it myself. The reason I suspect the evaporator is because everything else related to the AC under the hood is all brand new. The only thing left old is the evaporator. Also I did not see any die indicating a leak anywhere under the hood.
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
It is a 1975 so obviously a small block. Since the whole thing can be done from under the hood I will most likely do it myself. The reason I suspect the evaporator is because everything else related to the AC under the hood is all brand new. The only thing left old is the evaporator. Also I did not see any die indicating a leak anywhere under the hood.
Racer
Joined: Aug 2018
Posts: 266
Likes: 52
It is a 1975 so obviously a small block. Since the whole thing can be done from under the hood I will most likely do it myself. The reason I suspect the evaporator is because everything else related to the AC under the hood is all brand new. The only thing left old is the evaporator. Also I did not see any die indicating a leak anywhere under the hood.
A refrigerant detector is expensive but it would be probably help a lot.
The aluminum pipes tend to get stuck at threaded fittings like siezed together.
Last edited by Greengear; Jan 7, 2019 at 12:55 AM.
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Race Director
Joined: Jul 2015
Posts: 13,082
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From: SW Florida.
just because everything is new, doesn't mean it is not a bad new part or a nicked O-ring on installation. rule of thumb. if you just did something and something else went wrong-YOU JUST DID IT!!! double check your work. use dye. find the leak. possible even likely you are right. but be sure.
Burning Brakes
Joined: Oct 2001
Posts: 925
Likes: 200
From: TX
I think your best bet to check the evaporator is with an electronic leak detector. They can be rented for around $20 I believe.
Stick the sniffer in the center a/c vent with car running, ac and fan on. If there is a leak it will find it. Chased a leak in my 280zx and found it this way when everything else failed to find it. ( I ended up buying a sniffer!)
Happily, my vette a/c is koool.
VERYSOON
Stick the sniffer in the center a/c vent with car running, ac and fan on. If there is a leak it will find it. Chased a leak in my 280zx and found it this way when everything else failed to find it. ( I ended up buying a sniffer!)
Happily, my vette a/c is koool.
VERYSOON
Drifting
Joined: Nov 2000
Posts: 1,390
Likes: 39
From: North Brunswick NJ
I changed my evaporator on my 72 sb 3 months ago. I worked with a mechanic, as I did not have all the tools and a full lift to do the job. He did not work on the car, unless I was there to work with him. We used the following, excellent posting from fellow forum member as a guide..
https://www.corvetteforum.com/forums...-cleaning.html
https://www.corvetteforum.com/forums...-cleaning.html
Safety Car
Joined: Mar 2003
Posts: 3,583
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From: Indianapolis IN
Finalist 2020 C4 of the Year - Unmodified
C4 of Year Finalist (stock) 2019
Interesting thread. First, you say the AC would not work on the way to the body shop after the car sat for two weeks. Did the system work satisfactorily before sitting? I will not assume it did, as you didn't state in your original post whether or not it was working fine right after the rebuild, but before the trip to the body shop.
Secondly, I see a lot of discussion about checking for a leak. Don't start chasing problems that may not exist before you start at square one. Have you checked to verify whether or not you even have refrigerant in the system? What were the results from your static pressure test? Start there. You say your car is a '75. Did you restore the system to 100% original including installing a rebuilt V.I.R assy? Those rebuilt units are notorious for sudden failures. Many possibilities here, but NONE should be explored until you know the basics first...
Secondly, I see a lot of discussion about checking for a leak. Don't start chasing problems that may not exist before you start at square one. Have you checked to verify whether or not you even have refrigerant in the system? What were the results from your static pressure test? Start there. You say your car is a '75. Did you restore the system to 100% original including installing a rebuilt V.I.R assy? Those rebuilt units are notorious for sudden failures. Many possibilities here, but NONE should be explored until you know the basics first...