I am having some heat issues on my 93 I have had the thermostat changed and the electronic climate control checked and I am hearing alot about clogged heater cores. Mine is definately not leaking because I had that checked out also. I read somewhere that you can flush or blow them out I think. The buttons on the climate control are a bit touchy so sometime it is hard to tuen on and when it does turn on sometimes it won't turn off. I was told that if I get a new reconditioned one that will solve the problem but a friend of mine is having the same button problem and when het sets his to 80' he is sweating i have to put mine on 90' just to get warm.

Any help would be great.

 

Do a forum search on this subject. I have posted tech tips on both of these the past two months.

1. The auto climate control box is easily removed from the dash, disassembled at home and the internal button contacts cleaned. This will make the buttoms work as new. Try this link. If it does not work do a search.

http://forums.corvetteforum.com/show....php?t=1519199

2.This fall I flushed my heater core by disconnecting the hoses under the hood on the passenger side and hooked it up a garden hose. I do not think this was my problem. In the heater hose is a plastic orfice (on my '96.). It is about 3" long and is right under the expansion tank. Other years may not have the orfice. GM calls it a valve. Inside it is a spring loaded washer that closes at high rpm's. At high rpm it makes the hose inside diameter smaller. I think it is designed to reduce pressure or flow at high rpm's. I found debris clogged in the center of the orfice that was restricting flow even at idle. It cleaned it out with a hose. I installed the new orfice I purchased before starting (Under $15) and broke the old one apart with a hammer to see what was inside.

These two repairs fixed my button problem and gave me heat in one afternoon.

If a search does not turn up the help you need then email me at TiIngot@aol.com

 

should I drain all the antifreeze first before iI attempt this.

 

Definately drain the coolant before trying to flush the heater core (Might as well flush the entire system at this point). That heater control valve is (GM p/n 10157988 Heater flow control valve w/o hoses 8.866 (also ACDelco 15-5423)). I just replaced mine last week after it cracked.

I also did the TB bypass while I was at it...not so much for performance, but it looks a lot cleaner Simply use the upper Rad and heater hoses from a '95 and you eliminate having to run tee's.

 

Thems h/c tubes aren't the sturdiest things, so be very gentle when removing the hoses and when flushing. You do not want a leaking h/c in a C4!
At one point, I purchased a small jug of cooling system cleaner and put that in the rad before I did a complete system flush. Then I did a reverse flush.
Seemed to get a bunch of junk out.
Can you verify if the temp door is moving as it should?
How is the quality of vacuum at the climate control programer?

 

I had the whole heater system checked at Corvette Paramedics in NJ I think they do great work and they told me that the temp door was wirking fine. THey did replace the thermostat and coolent. They pust the blame on the electronic climate control unit and the buttons being touchy, but now I have been reading alot of tech forums on this issue something is telling me that it might me this heatercore flushing. because the buttons do work sometimes more when it's cold but i can get the unit to turn on and off and the other buttons work most of the time. the temp button and the fan button work all the time for me.

also is this flushing the heater core a really big job because if it is i think i might just get them to do it. thanks again