Heater is leaking coolant
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Heater is leaking coolant
This moring on the way to work I smelled, then saw antifreeze in my car! Fortuantly most of it leaked to the outside.
Does this mean that the heater core needs to be replaced?
Is there a place that can leak within the heater box that just need to be fixed?
What is involved in replacing the heater core? I plan to go to a track day tomorrow, is it ok to simply bypass the heater core?
thanks,
~Jay
Does this mean that the heater core needs to be replaced?
Is there a place that can leak within the heater box that just need to be fixed?
What is involved in replacing the heater core? I plan to go to a track day tomorrow, is it ok to simply bypass the heater core?
thanks,
~Jay
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
As long you do not have A/C it is pretty easy to replace, just remove the heater box cover on the firewall and it is right there. I got a replacement heater core at the local parts stores. Bypassing is easy but the hoses are 2 diff sizes.
BTW my heater box seals where gone so I used RTV and cut a peice of rubber to slide the core hose ends through and screwed that to the firewall with RTV sealing it also.
BTW my heater box seals where gone so I used RTV and cut a peice of rubber to slide the core hose ends through and screwed that to the firewall with RTV sealing it also.
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
I'm sure I won't be the first person to suggest this, but check any replacement heater core BEFORE installation 
I tested my replacement by dunking it in a 5 gal bucket of water, and pressure testing via an airhose.
I was fore-warned by fellow C3'ers here on the forum; due to poor quality of aftermarket parts.
I tested my replacement by dunking it in a 5 gal bucket of water, and pressure testing via an airhose.
I was fore-warned by fellow C3'ers here on the forum; due to poor quality of aftermarket parts.
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Originally Posted by Stewart's74
Mike is right. I had to do the job twice because the first core I bought leaked worse than the original...Got the second one pressure tested and it checked out ok.
does GM make a replacement part? GM parts are usually better than aftermarket stuff.
Another tip I learned today- When you are working on you car in the parking lot at work:
1. Make sure hte boss has already gone to lunch
2. If it is windy outside BEWARE of falling hoods!!! Thankfully I was able to catch it before it hit my head... then I noticed that there is a little hole in the bar that holds the hood up.... I stuck a long screwdriver through it to keep my head safe.
~Jay
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Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
I went to the Paragon site, and they have a Delco OEM core for $87, they also have POS core for $58. I think I'll get the Delco 
What else should I replace while I'm in there? I'm glad I don't have A/C to deal with.
~Jay
What else should I replace while I'm in there? I'm glad I don't have A/C to deal with.
~Jay
Tech Contributor
Joined: Aug 1999
Posts: 15,175
Likes: 3,990
From: Connecticut, USA
Jay, the non a/c core isn't too bad to do and some guys have done it from the engine bay. There are a couple of clips in there so be careful removing them. DO rig up a low pressure hose setup in a pail of water and check. Don't sold that the more expensice one is the better one. You can get a heater box gasket kit too if you want to go through the whole thing.
Good luck,
Gary
Good luck,
Gary
Burning Brakes
Joined: Feb 1999
Posts: 1,190
Likes: 1
From: SIMI VALLEY CA
Jay,
Youre in for a lotta fun
You will find out how your car was built on the assembly line. They start out with a heater core then put EVERYTHING else around it. 
Easyist is to bypass it. I've had mine bypassed fo quite a whilr and only miss once in a great while. But then I dont remember the last time my tops were on either.
If you want to hang out with some local corvette people let me know.
Youre in for a lotta fun
You will find out how your car was built on the assembly line. They start out with a heater core then put EVERYTHING else around it. Easyist is to bypass it. I've had mine bypassed fo quite a whilr and only miss once in a great while. But then I dont remember the last time my tops were on either.If you want to hang out with some local corvette people let me know.
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Originally Posted by JIM
Jay,
If you want to hang out with some local corvette people let me know.
If you want to hang out with some local corvette people let me know.
What are you doing tomorrow (wednesday)? I will be at Willow Springs in the morning and plan to go to LACR in the evening. It would be great to have someone to talk toat LACR that doesn't wear their pants around their butt.
I think I may install an aftermarket A/C unit. since I have so much work ahead of for the heater core.
I don't want to bypas it because on those cold desert nights the heater makes driving with the top down more comfortable.
~Jay
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
why not go to your radiator shop and have them re-core your core? You will be guaranteed of a good unit that fits...the replacement, even the gm don't fit that well and you will be swearing up a storm during install.
I did mine, only cost me 35 bucks to have it recored...they used my tank and it fit like a glove.
I did mine, only cost me 35 bucks to have it recored...they used my tank and it fit like a glove.
Burning Brakes
Joined: Mar 1999
Posts: 1,047
Likes: 3
From: CA
I bought a new replacement gm and didn't have any problems. Before you start make sure you have all the soft parts for your car such as any seals and gaskets. Doc Rebild is a great place for this because of the great diagrams and quality parts. If your heater hoses haven't been replaced in a while you may want to get a set as well since you will be disconnecting them. On my 71 they have molded curves making the installation that much simpler.
Take your time, have the right parts on hand and you won't have any problems.
Take your time, have the right parts on hand and you won't have any problems.
Intermediate
Joined: May 2003
Posts: 42
Likes: 0
From: pittsboro NC
Jay, Be sure that your heater hoses are connected to the core good and not leaking (can sometimes give a false core leak). Also be very gentle with it when replacing the new core. The lines are very fragile and can be broke easily when fitting and replacing. Good Luck
David
David
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Originally Posted by SmokinL82
Jay, Be sure that your heater hoses are connected to the core good and not leaking (can sometimes give a false core leak). Also be very gentle with it when replacing the new core. The lines are very fragile and can be broke easily when fitting and replacing. Good Luck
David
David
How do I know for sure if a hose is leaking vs. the core?
~Jay
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Originally Posted by gtr1999
Jay,
If you have the new one or old one out you can test it like this if you have acess to compreesed air. Set it at 20 lbs though, not 100 psi and see.
Gary
If you have the new one or old one out you can test it like this if you have acess to compreesed air. Set it at 20 lbs though, not 100 psi and see.
Gary
Eddie
Team Owner
Joined: Jul 2004
Posts: 23,957
Likes: 174
From: South West - but north of Dayton, Ohio
I feared that exact issue... and as much as my son rides with me - I feared him getting burned. I have permanently bypassed my core (yeah - it's a fair weather car anyway) underneath by the frame rail. A quick purchase at the local hardware store for a piece of copper tubing - a couple of hose clamps - and we're heaterless. Also keeps the interior from getting so stinking hot in the summer. 
