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If any of you are going to replace your old heater cores soon, here is a part you will DEFINITELY need. The door inside the heater box has a metal rod that opens and closes it as you adjust the temperature up or down. The rod attaches to a lever assembly that moves it in or out. The little white plastic clip that holds the rod to the lever is no longer available. It's IMPOSSIBLE to find anywhere. As you start dismantling the heater box to get at the heater core, you need to undo the rod from the lever and the original white plastic clip WILL break! I found a replacement clip that works better than the original one. I got it at AutoZone. It's sold under the "HELP" brand made by Dorman replacement parts. It's where all the fasteners and clips are displayed. Part # 75450. It's a small assortment of clips. Use the black one. It works perfectly and was very easy to install. I paid $3.99. Well worth picking one up as sooner or later, you'll need it
Hi, my 1990 heater core leaks...is it worth a try to use heater core stop leak ?....its an $80 part & an $800 labor bill...I live in Az. & its 94 degrees in October... its disconnected now & the A/c blows colder...can a shade tree mechanic replace a heater core..thx
Hi, my 1990 heater core leaks...is it worth a try to use heater core stop leak ?....its an $80 part & an $800 labor bill...I live in Az. & its 94 degrees in October... its disconnected now & the A/c blows colder...can a shade tree mechanic replace a heater core..thx
If you use stop leak, it's not going to hold. That stuff is for a temporary fix until you get it replaced. Look at it this way....... the metal heater core has a hole in it. Powder or liquid is not going to do much for a permanent repair. Don't waste your money. Replacing the heater core can be done by most somewhat skilled owners. About 8 hours work. Take your time and bag and label each part you remove until you get the core out. Reverse the procedure getting it back in. It's not hard if you take your time.
One of the challenges of replacing the heater core in my '84 was the top bolt to the brace between the door frame and the dash panel support bar. Here's my answer: This bolt has a 12mm head, which fits a 1/2" box wrench okay. My 1/2" long extension fit into the open end of my box/open end wrench, which gave me enough leverage with my 1/2" ratchet wrench.
One of the challenges of replacing the heater core in my '84 was the top bolt to the brace between the door frame and the dash panel support bar. Here's my answer: This bolt has a 12mm head, which fits a 1/2" box wrench okay. My 1/2" long extension fit into the open end of my box/open end wrench, which gave me enough leverage with my 1/2" ratchet wrench.
Any chance of doing parking lot surgery....removing the core from the firewall side??? I had to ask.
You chose the right word . . . surgery. If you want to try that, bring your Sawzall. It won't be pretty!!
I didn't need that little clip that FourSpeed said that you'd need.
Were you actually able to keep your old one intact and reuse it? They're very brittle from age and can break very easily. It cannot work without that clip holding the rod in place.
azmark6corvettes- you can replace the heater core yourself. I replaced my 87' core last year. Send a request to cesmachines@yahoo.com and I'll send you the procedure with photos in PDF format. When you do it yourself, you know it was done right.
Hi, my 1990 heater core leaks...is it worth a try to use heater core stop leak ?....its an $80 part & an $800 labor bill...I live in Az. & its 94 degrees in October... its disconnected now & the A/c blows colder...can a shade tree mechanic replace a heater core..thx
I am in the middle replacing my heater core in an '89. What is the black part that the metal rod attaches to? It operates the door, has an electrical bundle attaching to it. The arm on mine snapped..... I thought I would order a new one instead of attempting a glue together.
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Originally Posted by bodoggie47
I am in the middle replacing my heater core in an '89. What is the black part that the metal rod attaches to? It operates the door, has an electrical bundle attaching to it. The arm on mine snapped..... I thought I would order a new one instead of attempting a glue together.
Blend door (A/C - Heater) motor controller. AKA the blend door actuator. (That rod is attached to the blend door which swings to cover/expose the heater core and/or A/C coil to create different air temps).
Don't have the GM part number handy -- though I tried to find it on eBay.
Basically, it's a stepper motor who's position is controlled by the "brain" in your dash. The brains of the system includes one more part above/behind the accelerator pedal. FYI...when you replace the part, it will "relearn" the limits of travel after you disconnect/reconnect the battery. It goes into "learn" mode during the first 2 minutes of startup (after reconnect).
I'm fairly sure the controller automatically jumps to the "AUTO" position. If not, you'll want to push the AUTO button after turning the car on.
WWW.BATEE.COM is a website very detailed on C4 heater, A/C, dash issues.
Excellent tip for that part, my clip didn't break but it was very fragile, glad you recommended the replacement rod/clip part.
I also had to make a similar tool to break free that cross brace. I used a 1/2inch breaker bar, 1/2 inch extension and the 12mm box end wrench. You can see I used electrical tape to keep it together.
This is a straight forward job ("fast" method without removing top dash and taking out the passenger seat). But it sure was tough getting to those unseen top screws holding in the plastic black ductwork. The 6 to 10 hours estimate was right on for a first timer.
I still have the heater core bypassed in the engine compartment since its been so warm in los angeles, buts it great to know that I can weather a winter storm now with a simple connection when I need to.
I have a brand new ZZ4 short block engine I installed, transmission just rebuild, and a new heater core. My vette is 100% now
What does the part that falls off the inside of the heater box when you pull it off
What does the part do?
I also had to make a similar tool to break free that cross brace. I used a 1/2inch breaker bar, 1/2 inch extension and the 12mm box end wrench. You can see I used electrical tape to keep it together.
This is a straight forward job ("fast" method without removing top dash and taking out the passenger seat). But it sure was tough getting to those unseen top screws holding in the plastic black ductwork. The 6 to 10 hours estimate was right on for a first timer.
I still have the heater core bypassed in the engine compartment since its been so warm in los angeles, buts it great to know that I can weather a winter storm now with a simple connection when I need to.
I have a brand new ZZ4 short block engine I installed, transmission just rebuild, and a new heater core. My vette is 100% now [/QUOTE]
All your info was a great help but do you know what the piece does that falls off inside the heater box when you pull the box off? Is it a sensor of some kind? Thanks Chuck Watson 89 Z51
10-12-2014, 04:00 PM
84-89 C4 heater core replacement hint
Yes sir! That's the same part!
