Leaking Heater Core, Opinions needed, Thanks!

[bobmanx]

C2 Leaking Heater Core, Opinions needed, Thanks!

Well, it appears from all the checking, that the heater core is leaking and being forced through the heater/defroster/ A/C ducting to both sides of the Corvette floor. Its a C2 convertible, 327/350 hp, 4 spd, WITH A/C. What is the recommended way to plug, bypass, reroute, modify the heater hoses to make it driveable while I get the parts and the enthusiasm to replace the heater core.

Remember there are a few more parts to remove since the car came with A/C and some suppliers of the core seem a little less than knowledgable as to correct hoses and core for a A/C equipped 67. Which supplier and core is correct, some claim that the hoses are two different sizes, and the info gets worse from there. It appears to be 5/8 in on the top inlet under the hood and there is a vacuum operated valve on the lower pipe so who is a expert, as to whats correct and whats the proper way to patch it till I can get the "CORRECT PARTS"?

Thanks for all help and opinions.
Bob

P.S. Vigman are you still alive and how's your project?

 

[magicv8]

It's an ugly job. I am happy with a core that doesn't leak - the first one I did lasted only a week - then I did the job over. Both were recores instead of replacements. The second one has lasted 14 years - so any info I could give on suppliers is dated - except for this: The vacuum controlled valve is made of unobtanium. I saved my old brass valve - in case I want to make a TQ out of the car some day. The replacement valve and "replacement" vacuum switch came from LICorvette.

The job is A LOT easier if you remove the passenger seat.

Good luck

 

[IH2LOSE]

I would suggest just disconecting them where the connect to the motor/waterpump and tape off the end so no dirt gets in and leave the hose's saftley where they have no chance of causing trouble. Then purchase a short lenght of hose to connect the hose to the 2 nipples you disconected the hose's from so its just by passing,Good luck and its real simple.

 

[bobmanx]

Thanks for the suggestions so far. In following the hoses one of them "tee's" off to the radiator expansion tank, that's why I thought about just connecting the hoses together at the heater inlets, as if the heater core was still there, so the coolant could recirculate as normal.

Plugging them at the same heater connection location would also allow the expansion tank to stay connected and function as designed. I wasnt sure if the cooling capability of the system would be affected by one or the other ideas (Free flow or no flow, around the thermostat) and what was the best to keep the cooling system from running too hot, and causing other problems.

Not planning on this as a permanent fix, only a holding point until parts and time allow a full replacement of hoses and core, and so the car would be functional while it waits for parts and time to do it right.

Thanks for all ideas, Bob

 

[Ron Miller]

Connecting the hoses temporarily at the heater core is the right idea, I've done that before. However, I also believe you're right about the hoses being different sizes. I believe one is 5/8", the other 3/4", so it'll take some clamping or stretching to get them both sealed on the same size pipe.

rlm :cool

 

[Vettewine]

C2 Leaking Heater Core, Opinions needed, Thanks!

Until I replaced my leaky heater core with a new one (not a remanufactured one as it's too much of a chore to waste on a rebuilt) I just removed the two hoses from the heater and connected them together. You definitely want to leave the expansion tank in the circuit as it's actually what would be the top tank of most radiators but was relocated on C2s to keep the hood profile low. And the hoses are two different sizes but I used some pipe fittings I had around and made a "U-shaped" connector with two different size ends for the hoses. I probably still have it somewhere but I just moved last year and have no idea which box it's in now...!

 

[Vettewine]

heater cores...

D ("C5D") is correct and copper is what I used (but didn't specify - sorry) and it worked great! Of course, you know you have to pull the glovebox, etc. I think it's a good idea, unless you're a contortionist, to remove the passenger seat for ease of access. Good luck and let us know the results.

 

[JohnZ]

Coolant circulates through the core all the time unless the A/C is on, which closes the vacuum-operated shutoff valve. Do NOT disconnect the 3/4" hose at the water pump - that hose, from the water pump to the tee at the expansion tank, MUST stay in place so the tank continues to function as the coolant expansion/supply reservoir and system pressure relief point.

You can either pull both hoses off the heater core nipples and connect them together, bypassing the core, or you can modify it just like the factory C-48 (less heater) cars were:

1. Either plug the end of the 5/8" hose from the intake to the lower heater core nipple or remove it entirely and put a rubber bypass cap and clamp on the fitting at the intake.

2. Either plug the end of the 3/4" hose from the tee to the upper core nipple or remove it and put a rubber bypass cap and clamp on the end of the tee that faces the dash.

 

[bobmanx]

Thanks All.

It sounds like the best is to connect the two hoses and let everything stay the same as if the core was still there. Ithought it best to leave the expansion tank in the loop. Less modification, till all new parts are here.

It appears to be a 5/8 in "UPPER" core connection point, and the "lower" is out of sight as to core connection point, hose is covering it, after the valve. Are all the A/C equipped heater cores different tubing ends different size, (5/8 to 3/4)?

I'm also assuming that "red" heater hoses are not original, but were replaced sometime in the past.

And the core replacement job would be easier if the A/C wasnt in there just to make life more fun and interesting. I have the original "Corvette Factory Manuals" for 1963 and 1965 supplement. In reading through the process it appears easy but really involved! Do all the heater and A/C cables need to be disconnected to get it out from under the dash or can I leave them connected at the dash and get enough room to get the heater core out of its housing while its still in the passenger side floor area? The less disconnected, the less that gets broken, lost, or ???

Thanks everyone for the suggestions and warnings, I will keep everyone advised as to the progress and results. This appears to be one of those things that my chiropractor will be glad that I tackled! Bob

 

[Vettewine]

Heater core, etc...

Bob...

Yeah, the original hoses were black and I had to look around a little to get black replacements for my red ones. Most of the automotive parts houses carry the red but NAPA has the original looking black heater hoses. Good luck and don't forget to look into removing the passenger seat or you'll be seeing the chiropractor real soon!

 

[bobmanx]

Thanks All

As suggested in earlier posts, seat will be removed, and I have the luxury of time, once I get the core bypassed. Car is not a daily driver so it will get repaired with all new parts, hoses and clamps. I will check NAPA for hoses. I just wanted to make sure that it could be moved if needed, while it was in process, without causing too many problems. Thanks again for all the info.

Bob

 

[Jack44]

It was a $640.00 replacement...Fluid was pouring out all over shifter filling up boot and floor...A real mess...

 

[JohnZ]

Thanks All.

It appears to be a 5/8 in "UPPER" core connection point, and the "lower" is out of sight as to core connection point, hose is covering it, after the valve. Are all the A/C equipped heater cores different tubing ends different size, (5/8 to 3/4)?

Bob

Correct installation of the hoses is a 5/8" hose from the intake manifold nipple to the lower core pipe (that hose also has the vacuum shutoff valve in it), and a 3/4" hose from the water pump nipple, through the tank tee, to the upper heater core pipe. If your 5/8" hose from the intake manifold is connected to the upper core pipe (instead of the lower pipe), someone installed them backwards when they were replaced. Coolant always enters the bottom of the heater core for two reasons: 1) So any air bubbles can separate and vent through the upper pipe back to the expansion tank, and 2) So the customer doesn't hear any "gurgling" noises from the heater core inside the inner box. That's why the hoses, nipples, and fittings are two different sizes, but that doesn't stop Bubba if he's really determined.

 

[bobmanx]

JohnZ, thanks for the info. The "Factory" Manual didnt say anything about sizes. It did show a diagram of the lines and I was planning on following that as gospel. I will make sure that "Bubba" is off to the movies when I do this, so he preocupied with all the pretty pictures, rather than helping on the Corvette! LOL

As always you are a source of information that is helping the rest of us to get it right.

Thanks , Bob