Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductions?

[Scott S.]

Car: 1967, L79 with C60.

I located a GM NOS air conditioning evaporator core, part number 3007632. I can't find that part number in the 1967 AIM, but a TDB archive search showed a post dated August 9, 2006 where Pete Lindahl noted: "The Parts Book shows P/N 3007632 for the 66-67 Corvette evaporator core w/ fittings and shows P/N 3159719 for the 1963-65 Corvette evaporator core w/ fittings."

It sounds like this part number may be a service replacement part, which would explain why it is not in the '67 AIM, but listed in the Parts Book as applicable for 1967. Is this understanding correct? Should it fit and function as well or better than currently available aftermarket or reproduction evaporators?


If evaporator core p/n 3007632 is applicable to 1967, is it likely to be a better quality part (being GM new old stock) than currently available aftermarket or reproduction evaporator cores?

I suspect the answer is "yes", but when it comes to parts like A/C condensers, evaporators and radiators, I don't know if age brings risks that would not apply to current aftermarket/reproduction parts of this type.

[Jack H.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

I suspect it's not in the AIM because the ENTIRE heater box came from Harrison as a finished assembly and it included the evaporator...

[Larry M.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

A quick search on the internet shows that the 1966 and the 1967 evaporator cores carry a different part number. It may be because the 1966 used an STV valve whereas 1967 used a POA. These valves were direct coupled to the evaporator outlet connection....which may explain the difference.

More checking is needed before purchasing.

Larry

[Scott S.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

I suspect it's not in the AIM because the ENTIRE heater box came from Harrison as a finished assembly and it included the evaporator...

Thank you Jack, that makes sense.

[Scott S.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

A quick search on the internet shows that the 1966 and the 1967 evaporator cores carry a different part number. It may be because the 1966 used an STV valve whereas 1967 used a POA. These valves were direct coupled to the evaporator outlet connection....which may explain the difference.

More checking is needed before purchasing.

Larry

I compared the pictures of the 1966 & 1967 A/C evaporator cores on Corvette Central's website (below), and while these are not NOS units, they do have differences where the fittings connect. If the original GM units were also different, my concern is that even if the original GM (and NOS service replacements for '66 & '67) were close to being the same, "close" won't be "close enough" to reach the parts needed to connect the evaporator to the rest of the system.

I was up late last night trying to remove my A/C evaporator core from the box so I could compare it to the pictures, but so far, the box has won. I'm bringing better tools to the fight this evening.

[Scott S.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

I'm positive it's not supposed to come apart like this, but the evaporator core wouldn't let go of the POA valve and I didn't have wrenches here large enough to grip the POA valve nuts. I tried the adjustable wrench, but stopped before I broke something or put gouge marks in them. Some might say the evaporator core won, but I did manage to pry it out of its box

I don't know how to tell for sure if it's original, but it has the Harrison foil tag on it. One side looks almost new, the other side will have to be cleaned up a little before I can see it better. If the dirty side turns out as nice as the clean side, could (should?) this evaporator be restored?

[Scott S.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

After experiencing first-hand how tightly the evaporator core is packed into the evaporator box, I don't see how the 1966 model (or anything not designed specifically for that space) could be made to fit into the box, never mind the problem with the lower end pipe curving up across the fins too far on the 1966 example (see earlier comparison picture post), so that the POA valve wouldn't have enough room to fit.

[Scott S.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

There was one spot on the outside of the evaporator box that has been protected all these years, under the adhesive on the back side of the Harrison foil sticker that was on the outside of the box. I read discussions in the archives about whether the evaporator box was originally flat-black, semi-gloss black, or gloss-black.

I don't know what this would be called, but it looks glossy to me. I tried to show that reflections can be seen in the black, it's that shiny. Those are my fingers holding the camera reflected in the black strip in the first two pictures, the last one is a reflection of the overhead light. It's not mirror-like, but it's certainly reflective.

[Dick W.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

Soak those fittings in your favorite snake oil (penetrating oil) for a day or two before you tackle them again. Working with old cars as long as I have, my vote would be to replace the evap core. It is worth $300 or so dollars to not have to remove this bugger next year and then replace it. Aluminum does deteriorate over the years and with the oil and internal corrossion, would be next to impossible to repair.

[Scott S.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

Soak those fittings in your favorite snake oil (penetrating oil) for a day or two before you tackle them again. Working with old cars as long as I have, my vote would be to replace the evap core. It is worth $300 or so dollars to not have to remove this bugger next year and then replace it. Aluminum does deteriorate over the years and with the oil and internal corrossion, would be next to impossible to repair.

Thanks for the reply Dick, I will clean up the old evaporator and save it for a reference piece. I definitely do NOT want to do this job again. I don't think I could even do it without taking the engine out.

So the next question then, am I risking any similar problems with an NOS evaporator, or should a GM NOS unit be fine, assuming I can find one that will fit?

If I am better off with a brand new unit, that's fine too, I'm just trying to figure out what the best quality solution would be, so it will last a long time before needing to be replaced.

[Scott S.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

Here are the pictures I received of the NOS evaporator. The first picture is a comparison between the NOS (top) evaporator and the one that came out of the car (bottom). The other three pictures are the NOS evaporator by itself.

The bottom plate looks a little different, not sure if that is a big deal. What looks like a problem is the pipe on the left side doesn't bend out away from the evaporator before curving around to go across the front of the evaporator where the POA valve connects. I'm guessing the STV valve for '66 must be shorter.

I don't think the POA valve would fit with this p/n 3007632 evaporator, unless that pipe could be replaced with a pipe for a '67 and welded on.

[Scott S.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

I checked the LIC catalog (see below), and theirs is similar to the offering at CC, showing a different pipe configuration between '66 & '67. For both CC and LIC, the '67 pipe/fitting is angular, not smoothly bent like the original, and that part is visible in the engine bay where it connects to the POA valve.

I don't suppose anyone offers a USA-made and correct appearing replacement A/C evaporator? Or is it reasonable to weld a correct pipe-fitting in place of the incorrect pipe on either a NOS or a current-production Evaporator?

This car won't be on the road for a while yet so I'm not in a big hurry from that standpoint, I'm just trying to figure out whether to pass on this '66 NOS unit, and if so, then figure out the best solution to this problem. Please let me know what you guys think, I don't know if I've wandered off into the tall grass on this, or if I'm on the right track.

[Mike G.]

Repro Evaporator

Scott: FWIW I purchased a repro -65 evaporator from Old Air Products of Fort Worth and it was a perfect match to OEM. Popped right in, sealed it up with Doc Rebuild's seals. No sweat. (the box was on the bench)

The original evap still looked fine, and had passed a pressure test.... but the thought of having to EVER pull that *****' out -- horrible prospect.

The new evap was one of the wisest decisions I made during the restoration.

Now, my decision to cheap out and get a reman'd A6 compressor...win some, lose some. At least it's easy to R&R.

Mike

[Scott S.]

Re: Repro Evaporator

Scott: FWIW I purchased a repro -65 evaporator from Old Air Products of Fort Worth and it was a perfect match to OEM. Popped right in, sealed it up with Doc Rebuild's seals. No sweat. (the box was on the bench)

The original evap still looked fine, and had passed a pressure test.... but the thought of having to EVER pull that *****' out -- horrible prospect.

The new evap was one of the wisest decisions I made during the restoration.

Now, my decision to cheap out and get a reman'd A6 compressor...win some, lose some. At least it's easy to R&R.

Mike

Thanks Mike. I'm convinced. Even if the Harrison evaporator that was in there looked perfect and passed a pressure test, it's too difficult of a job to risk having to do it twice.

I will contact Old Air Products to find out about their Evaporator.

[Jim T.]

Re: Will 1966 GM evaporator (3007632) work for 1967? Better quality than reproductio

Scott one of the best things to happen to me was the inability of the local Chevrolet dealership employees to remove the evaporator in my 1970 Corvette in 1988. My 70's air conditioning system was not operating correctly and I was out of town on business. I told my wife to take it to the dealership.
The dealership technitions could not disconnect the largest connection to the evaporator and did not do anything to get the air working. Did charge for their time.
I got home and started reading my service manual. It was right there in the serivce manual what to check. I did and found the Expansion Valve screen cloggled with desiccant from the dryer/filter. Cleaned the screen (metal), flushed the flow lines from the dryer to the expansion valve, and replaced the dyrer/filter. Took it to a shop to have vacuum pulled on the system and recharged with R12.
Air conditioning in my 1970 is still operational. The inability of disconnecting the large fitting was a good thing.