BLUE1972

How bad is it .....

Will be helping a friend replace a leaking evaporator on a NCRS 67 Original air Car.

I've done many C3's heater cores but as luck wound have it no A/C cars.

It's a small block, luckily.

Will probably get it from Ricks, Wilcox or Paragon.

The car is mint so that makes it worse. At least the garage has A/C.

DUB

It is no picnic. but yet it is obviously not impossible. I have done one.

DUB

emdoller

Powershift

Excellent point.............I would like to hear the answer. There is generally only one way and it involves an AC electronic tester.

A friend told me his evaporator core in his C2 was leaking and replaced it. He added air conditioning to his shop part of the way thru this job here in Louisiana in July. Turned out when all was said and done that he had a fitting leak.

I would rather break my arm than do this job..............at my age my flexibility and agility is long gone. But as Dub said it can be done. Engine can stay in car, but evaporator box in/out is difficult and likely done in a few pieces instead of as a completed unit.

Larry

EDIT: Make sure you leak check the new replacement at 50-75 psig pressure and do an underwater bubble check.

EDIT2: Just recently helped a friend do this on his C3 car. Car is undergoing restoration at this time so a lot of things are apart or easier to do. We pulled the new/rebuilt engine back out of the engine bay so that we could install the evaporator box in one piece...........the way it really should be done. If we had not pulled the engine, even with the car already part apart, we would of had to install the evap box in multiple pieces.

EDIT3: If you go this far, should you also just rebuild the entire heater box as well?? Project creep........

DUB

I can say teat there is NO WAY IN HELL that the complete box can come out as a unit WITH the engine in the car.

The reason I know this. Is because I had to put a complete unit in a 1966 that had the engine in the car and there was no way. I had to assemble it piece by piece. TRUST ME..I tried.

DUB

DUB

BLUE1972

My friend had an A/C shop test the unit. The electronic tester started bussing from the vents. (as per him) . The shop owner told him it was the evaporator and he wouldn't do it. Didn't charge him for the test.

I was going to try to borrow a tester and check the fittings when I get over to his place.

I thought it would be a real PIA and from what it sounds like it will be.

The car is spotless and was " restored" a few years ago (98 point car) , kept in a climate controlled garage - so this may help.

mark6669

Its not as bad as everyone thinks to replace the core but you are going have to be extra careful not to scratch the parts. You have to remove everything down to the bare box and core ( hood latch, heater hoses, tank, a/c hoses and valves) them remove the outer shell to get to the core. Wrap the engine to help prevent scratches. Just go slow and tape anything that looks like it might rub.
Mark

67vetteal

I am in agreement with DUB. Years back I installed factory A/C in my 67 coupe. I removed the entire surround panel to gain access to the Firewall area. In retrospect it is not too hard to just lift the engine out, unbolting at the bellhousing. Regards, Al W.

DUB

And it is as bad as it seems due to shops will often times do not want to do it. Like I wrote...it is NO picnic...but can be done.

Al,

Trust me..I did consider pulling the engine and putting the entire unit in as one piece.

I opted out to assemble it in the car due to the car was also cream puff.

DUB

GearheadJoe

I removed and replaced the evaporator core in my '67 about five years ago, with the engine in the car. I can't recall all the details of the procedure, other than the fact that I considered it to be the most tedious job I have ever done on my Corvette.

To put this in perspective, I have done just about every job there is on my car, including removal and replacement of the engine, the transmission, the differential, and the entire suspension.

The main problem with the evaporator box is all of the tiny screws that are almost inaccessible except to a contortionist. There are even a couple that have to be removed from the cabin side of the firewall.

I think the best defense against terminal frustration is to have a lot of patience, lots of adapter do-dads to get a 1/4" socket wrench into difficult locations, and a good mirror to see into obscure places.

I don't recall having to take out the evaporator box in pieces, but I may have installed some of the external control hardware after the fiberglass box was installed.

The main thing I remember is how tedious it was to get all those tiny screws out and then reinstalled. And if I recall correctly, the worst ones were on the fender side of the box, rather than the engine side.

I do not think that pulling the engine is worth the extra effort for what you would gain. Worst case you might decide to pull the passenger side exhaust manifold.

DUB

'GearheadJoe'

I agree that the word 'tedious' DOES apply. AND yes..out of all of the years of working on Corvette that job still remains on the top ten of those repairs that were a challenge.

I used drift pins to get the case together so I could install the screws...and it was FUN.

When I was trying to install the evaporator case as a unit. Even with the valve cover off ..if the exhaust were removed. There was not going to be any room to get that box to fit in without damaging something. Because IF I could have done it that way..I would have.

DUB

GearheadJoe

I honestly don't recall the details of how I did the removal and replacement, but maybe that's because it was so tedious that my brain has blocked it out. The main thing I recall is how frustrating it was. However, I know for certain that the engine remained in the car throughout the entire process.

In thinking about this now, I suspect that the procedure I used was probably based on what the GM shop manual shows. I'm away from home today so I can't check what the manual says.

While there are certain maintenance procedures on our Corvettes that are frustrating, I don't think GM would be silly enough to make this job "impossible" to do with the engine in the car. Their dealer's mechanics would have complained loudly.

That being said, one of my Corvette friends also has several stock rear-engine Porsches. One of them has such a crowded engine compartment that the engine has to be removed to replace the spark plugs!

DUB

OH YEAH...That seems like they had there act together on that one when they designed it.

There are some areas on these Corvettes where they had a serious hiccup when drawing out the plans that I have encountered. They forget that it will more than likely need servicing at some point.

I have to stop and ask myself. "What and the heck where they thinking??"

DUB

Mike Geary

If the evap core is leaking, you can pull the blower resistor off and stick the leak probe down into the housing. Should get a clear result either case.

BLUE1972

Thank you all for the help and info...

the more I think about this - I tend to think I will talk him into a "winter " project where time does not matter.

At least we will have 3 months to work on it.

Thanks again..

DUB

There is only so much Freon in the system and if there is a leak...it will soon run out.

Then it may require ADDING Freon to the system to find the leak.

If the system runs dry on Freon for too long...then the dryer in front of the radiator support will ALSO need to be changed as a precautionary measure. Not saying that that might not be a bad idea to replace it.

But if your friend is worried about ORIGINALITY.. The job needs to get started so a vacuum can be put on the system and it charged back up and NOT wait til winter.

As long as the system still has Freon in it you are OK. But even when you are doing this.. CARE MUST BE TAKEN when all hoses are removed that you seal them off and get the JOB done as quickly as possible. The longer the system is OPEN..and moisture can get to the dryer...the worse it can get.

DUB

DUB

beekppr

When I removed my body off the frame, that's when I pulled mine. I put it back in before setting the body back onto the completed frame assembly. I remember then thinking how much trouble it was and that was me having 100% clear access with the body sitting high on a rolling jig.

Knowing what I know now, I would probably not attempt it on a nice car with the engine in it. If it's original like mine was, everything seems to be glued together and it takes a lot of patience to get all the pieces apart without damaging stuff.

I think I'd look for an excuse to pull the engine and do both as a winter project. Maybe there is and annoying oil leak at the rear of the pan or you want a new cam or clutch assembly. Might as well get some other benefit from all that miserable work.

Another consideration might be to just lift the body off so you have way more access and less chance of damaging paint. I know it sounds extreme but I have had mine off and on a couple times and it's not a horrible job. A day off and a day on. Like the engine idea, it gives you an excuse to do a bunch of other things to just about anything on the car that was always on your to do list.

By the way, you are a hell of a good friend to help him out on this. Like someone else said already, I too think I'd rather suffer broken bones than do that job while the car is together.

BLUE1972

We have been friends for a long time and his health is failing.

I may try to keep a small charge in the system - it's not dead and was converted from the R12. Thus the system will stay "closed" . He said it pissed when he pushed the Schrader valve stem. (pull the compressor wire also)

I'm thinking you are right - pull the engine & in a few hours and it's out.

The paint is spotless as is the rest of the car.


I'm hoping to hook up with him this weekend and go over the car.


I'll let you know what I find.. hopefully it's a fitting ?

beekppr

Wouldn't that be nice? If you have a way to save the r12, it might be worth replacing all the o rings and schrader valves first just to see if it's something inexpensive and simple.

DUB

He stated that it was converted over ..so NO R12 is in it.

But regardless of that. The car should be taken to an AC shop and have the Freon sucked out of it.

DUB