Hi Group.....

SO ........ How tough is it to replace the heater core in a 76?

I just changed one in my 81 and I wont ever do one again! It can be done but you must take out the glove box and A/C duct work also you must get under the car to take the heater hoses lose.The main thing to  remember is the car is old and don't force or get ruff with anything because it will break.

I concur, mine is a 74 and it was also a PITA. You might as well replace the hose's while you're at it, even if they look good. You may have to reseal the hole in the firewall were the hose goes through, otherwise you'll get heat and possible fumes in the cabin. 

It does take some time, like 3 hours.  It is labor intensive, but it does not have to be that bad.  I would not want to go throught winter without a defroster and heater.  Simple and straightforward in my 73 roadster. 

Here is a link on what had to be done on a 70, should be the same on your 76 if you have a/c. http://www.corvetteforum.net/c3/juliet/heatercore/HeatCore_o rig.htm

I don't know if the 76's have a glove box but if they do the dash pad is all 1 piece and must be taken loose, but you don't have to remove the speedo cluster (like I did) It took me about 3 months to complete the change but actual work time was about 4-6 hours

Hi Group......

Thanks for the comments and the links.  For now I completely by-passed the heating unit so no coolant is going through the heater core (where it was leaking).

Since I just finished re-doing the interior from the frame up, I'll keep this as a winter project and tackle it then.

Spinny

I recently replaced the heater core in my '81 and it was a tough job.

I also said I wouldn't do it again, but you know what? Even brain surgery is easier the second time around...!

The big bonus was that once I (finally) got the heater box on the bench, i found that the door that closes off the heater core to give you the 'cool' setting wasn't closing all the way. That's why it was always warm in the cabin.

Big bonus seeing that we are having a very warm summer...!

It's a big job for the casual weekend mechanic but not impossible and very rewarding. Make sure you get a gasket/seal kit from Corvette America or whomever you deal with for spares before going in.

Neil