ac blowed up
Thread Starter
Racer
Joined: Oct 2007
Posts: 431
Likes: 22
From: Chester Illinois
ac blowed up
just bought a pretty nice 81 from a local. said he was putting freon in the ac one day and something went bang. anyway i bought it and got to looking around for the problem. on the right side of the engine comp. where the heater and ac lines go into a big fiberglass box i found the problem. at the bottom of the box is a hole you could put a baseball in. guess he had too much pressure applied. told him it was a good thing it blew out the bottom and not the top. might have tqken his head off. looks like this is going to be a major job to get to the problem. any suggestions.
Pro
Joined: Nov 2002
Posts: 599
Likes: 16
From: vista CA
congrats on getting the 81!
It sounds like the ac evaporator blew out - it is located within that big plastic box (along with the heater core) and it is a big job to get to. I have only got into this area of my C3 when the engine was out - real easy job then. I am not sure if you can do it with engine in or not - maybe others will comment.
You will need to patch up the 'baseball sized hole' in the glass heater/evap housing - that is much easier with it off the vehicle IMO. I would do a quick check before tearing it all down - plug one side of evap and blow into other - if by some small miracle it DOES hold pressure - maybe something else popped (compressor seal, etc.).
If you do tear it all down, it makes sense to put in all new seals - can get kits from vendors (like Doc Rebuild) for a reasonable price.
It sounds like the ac evaporator blew out - it is located within that big plastic box (along with the heater core) and it is a big job to get to. I have only got into this area of my C3 when the engine was out - real easy job then. I am not sure if you can do it with engine in or not - maybe others will comment.
You will need to patch up the 'baseball sized hole' in the glass heater/evap housing - that is much easier with it off the vehicle IMO. I would do a quick check before tearing it all down - plug one side of evap and blow into other - if by some small miracle it DOES hold pressure - maybe something else popped (compressor seal, etc.).
If you do tear it all down, it makes sense to put in all new seals - can get kits from vendors (like Doc Rebuild) for a reasonable price.
Drifting
Joined: Apr 2006
Posts: 1,911
Likes: 2
From: gold coast queensland
that is a classic story you have there. i think if you have a hole the size of a base ball under there you have some serious issues to deal with. you should be able to lay under there and use a torch look up into that aircon box... good chance your going to see one big blow out in the evapurator and some major carnage . bits of busted aluminium and stuff. god there must have been some serious pressure in there or a blockage. at the bottom of that box there used to be a drain point for the moisture probably about the size of an inch socket. ...you should have no drainage problems now haha... but seriously cause i have a right hand conversion i would have one hell of a time getting that thing out cause my steering stem goes through the side of the box but you should be able to unbolt the service nuts on the piping either side and get that box out of there.
Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
I got exactly the same problem, removing a cracked evaporator box, patching it, and installing it again :
http://forums.corvetteforum.com/show...1726044&page=2
http://forums.corvetteforum.com/show...1726044&page=2
Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
I have never seen an evaporator core blow up. the pressure relief/pop off valve should have been the first to go. the hole in the case may have come from something else. try and put freon in slowly and see where it leaks out. if you have a hole in the evap you will be able to tell very quickly 
Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
I have never seen an evaporator core blow up. the pressure relief/pop off valve should have been the first to go. the hole in the case may have come from something else. try and put freon in slowly and see where it leaks out. if you have a hole in the evap you will be able to tell very quickly
mine was cracked due to excessive heat from the 1/2 in. far away exhaust manifold, it was really frying and then maybe a small stone or something hit it and it cracked right away.
