HELP! How is an evaporator changed??

[Tom L.]

I finally got all my hoses onto the A/C system on my '72 and applied some pressure. The POOP hit the fan. Seems the evaporator is leaking. I pressure checked it when I had it out a couple of years ago and it held but today was a surprise, it leaked. How does one remove and replace an evaporator on a '72 big block? Please tell me it can be done.....

[Joe L.]

Re: HELP! How is an evaporator changed??

I finally got all my hoses onto the A/C system on my '72 and applied some pressure. The POOP hit the fan. Seems the evaporator is leaking. I pressure checked it when I had it out a couple of years ago and it held but today was a surprise, it leaked. How does one remove and replace an evaporator on a '72 big block? Please tell me it can be done.....

Tom------


The evaporator is the one component of the AC system that you don't want to have to replace. Since you do, I would follow the procedure in the factory service manual. The Mitchell flat rate manual gives 5.0 hours for this job on your car. However, I'll bet you can't do it in 10.

[Monte M.]

Re: HELP! How is an evaporator changed??

Tom,
The truth is, once you have all the heater hoses, A/C hoses, expansion tank, expansion valve and the POA valve, out of the way, it is really not that bad.
It may sound like a lot of things to remove, but you just put all that on if I am not mistaken.

The evaporator case comes in half. That in itself saves a ton of time.

Hang in there man.

Monte

[Tom L.]

Re: HELP! How is an evaporator changed??

Joe, So you think I can get it done in 10 hours?? How optimistic..

Monte, It kind of looks that way but I thouight I read that this was not a job that can be done without removing engine componenets, glad I'm wrong. I suspect that perhaps one of the welds where the tubes connect to the evap are cracked. I'm thinking it was a bad idea but I drove the car for two years after I pressure tested it with the lines capped and the TXV and POA absent so the lines were not supported. If that's the case is repairing these things worth it or is a replacement my best choice. Either way, any good sources new ones or do they come from the same factory in Asia? I see that Paragon has them for about $265. Is it worth the effort to find a "good" used one or is new a better choice?

[Randall K.]

Re: HELP! How is an evaporator changed??

I found that it was impossible to remove/replace the core box whole in my big block. I ended up removing all the screws that hold the halves together and removed/replaced the halves individually. Add more hours...

While you're at it, make sure you put new core box seals all around. I used the kit from Doc Rebuild. You may also want to consider placing a screen in the air intake to reduce the accumulation of leaves, mice, etc...

Last, don't forget about the box screw high up on the corner closest to the fender.

Good luck!!

[Patrick H.]

Re: HELP! How is an evaporator changed??

I have to do it on a 76 this year. There are some relatively good instructionals online, even on that other forum. Check those out and it will help.

[Monte M.]

Re: HELP! How is an evaporator changed??

As Patrick said: I did a search with "1972 Corvette evaporator replacement" and quit a few good sites came up. This is just one of them.

http://www.corvetteactioncenter.com/forums/c3-technical-performance/127690-ac-evaporator-replacement.html

Monte

[Tom L.]

Re: HELP! How is an evaporator changed??

Thanks, I saw that earlier. I just came in from the garage, the POS is out. I pressure checked it between one of the plates. Time for a new piece. It was fun though, perhaps more than I deserve.Any recommendations for a source? There are many sources and a range of pricing. I'd imagine that they all come from the same source but I'd like a piece that will last at least my lifetime : )

[Monte M.]

Re: HELP! How is an evaporator changed??

Tom,
My smog was not on my car when I did mine. Was you A.I.R. tube in place?
Did you find it easier to split the evap case in half?

Monte

[Tom L.]

Re: HELP! How is an evaporator changed??

No AIR in the car, I'm sure that wouold have made it more challanging. It was very tight getting it out, very little wiggle room. Most of the componentts that had to be removed were obvious but one seemed odd. The rear most exhaust manifold bolt had to come out so the box could move forward enough to clear the cuct work protruding from the fire wall. Things are very tight in these big block cars.

[Bill C.]

Re: HELP! How is an evaporator changed??

No AIR in the car, I'm sure that wouold have made it more challanging. It was very tight getting it out, very little wiggle room. Most of the componentts that had to be removed were obvious but one seemed odd. The rear most exhaust manifold bolt had to come out so the box could move forward enough to clear the cuct work protruding from the fire wall. Things are very tight in these big block cars.

This is exactly why I will never ever own a BB A/C car ever again.
way to many issues that do exist when the car is an A/C car.

I can change all 8 plugs on my 435 car in 15 minutes - try that one on a LS5 ac car!


Bill

[Tom L.]

Re: HELP! How is an evaporator changed??

Bill, Thanks for the PEP talk!!