Heater core?

[brucemc777]

Ewwwwww boy, I get the feeling I am going to be a regular here for some time to come.

Thank-you for existing!

Today was a nice Autumn day. The first, in fact, that I turned the heat on in the 1989 C4 I am driving now, on defrost. The windshield immediately fogged all up and I could smell antifreeze.

Does this dictate a bad heater core, or are there any other connections or hoses that could have caused this? I don't want to go off on only one item if I need to examine others-

Any advice from those who might have "enjoyed" the same experience?

I GREATLY appreciate all of your knowledge, experience and advice!!! No one left me any fortunes to just "take it to the garage to get fixed". I never worked on a nice car before and am more nervous than on my old trucks.

 

[DonB]

It sure sounds like the heater core to me. See if there is any a/f leaking under the passenger dash or if the carpeting is wet. I'd check into getting a FSM(factory service manual). You can get on CD from Central Corvette for $29.99.
It is a pretty big job. Any time you do in depth dashboard work I recommend removing the seats first of all. It'll give you a lot more room to work.
After removing the seats drop the bolster (lower panel)under the dash. Then remove the console shifter cover panel, the a/c and radio panel and that'll expose screws for removal of the upper dash(top) panel. There are also 2 small screws in the center defroster duct that hold the dash top on. DO NOT drop them down the duct! You will need a long 1/4" extension and a 7mm socket to get them. Keep all the screws separated as there are different sizes and thread patterns. I know...WTF! There is a lot of ducting, modules and wire harnesses to be removed and disconnected. Thankfully the wires only connect one way so you won't have to worry about cross-connecting them. This IS an exercise in PATIENCE! Put some pads on the floor because the majority of the work will be on your knees, kneeling next to the car. You might also want to take some pictures of it as you disassemble everything. It sure helps when you have a bunch of components and "NOW I have to put it all back together." Everything on this car is done sequentially. There is NO wasted space. It is amazing how they fit all this stuff in there. It comes apart in a certain order and HAS to go back together in just the opposite order.

Let me know if you get stuck. Also, while you are "in" there, you might consider replacing the evaporator for the A/C too. Your call.

 

[hcbph]

Sounds like the heater core to me. If you want to drive it for now and can live without the heater, take the 2 hoses off the heater core and loop them together (bypassing the core). Easiest way to test the core I know of is plug one end of the core where the hose attached. Basically the same thing on the other but rig in a cooling system tester and pump it up to about 18 lbs (the same pressure the cooling system cap releases at) and see if it holds pressure. I suspect it won't and you have a hole in the heater core.

Hope that helps. Good luck.

 

[brucemc777]

Thanks folks-

Looks like fun, using the alternate definition of "fun".

Nice that I am up in Michigan for the month and all of my tools are down home in Colorado Springs, CO.

Since I probably will be taking this down with me I guess I am in for a chilly ride mid-late November. Hope weather is nice those couple of days-

And am I ever going to hear about it from my wife when I take all the insides apart! I guess that's what wives are for - to remind you of all you do that has to have more work because it wasn't perfect in the first place...


EDIT:

I found the following in these forums - any opinion on if it will work in a 1989?

You don't pull the dash, instead, pull the passenger seat.

Pull the hush panel , drop the ECM and the door control module.
Remove the support bar going from the door pillar to the dash.
Use a 7mm to take the cover off the heater box.
Pull the cover, unbolt the core, re-install.

I removed the diagonal brace. There are 5 screws on the plastic cover for the core - 2 top, three bottom/sides. There are 3 screws retaining the core itself - 1 top middle & 2 bottom. As said, watch the position of the rod on the motor that opens/closes the door (if you have electronic controls). BTW, I also took out the pad in addition to the lower access panel - 4 nuts & much more room if you have full size American arms & hands. I got the upper screws restarted by placing a bit of tape on them & wedging them into my 7mm socket. It helps to have 1/4" drive flex adapters and every extension length they don't make Total time for me was about 5 hours for the heater core in-and-out.

 

[DonB]

Thanks folks-

Looks like fun, using the alternate definition of "fun".

Nice that I am up in Michigan for the month and all of my tools are down home in Colorado Springs, CO.

Since I probably will be taking this down with me I guess I am in for a chilly ride mid-late November. Hope weather is nice those couple of days-

And am I ever going to hear about it from my wife when I take all the insides apart! I guess that's what wives are for - to remind you of all you do that has to have more work because it wasn't perfect in the first place...


EDIT:

I found the following in these forums - any opinion on if it will work in a 1989?

Hi bruce. Your '89 should be awfully close(if not identical) to my '90. What year Vette is that quote referring to???? Sure doesn't sound like ours. Does yours have Electronic Climate Control? Mine does and it is complex. I've had mine dash, console and interior completely apart chasing an electrical Gremlin, which I fixed. There is a wire harness the size of your fist behind the passenger side dash along with ducts and modules. If there was an easier way to get at the heater core I'd have found it.
Just my humble opinion. Good Luck.

 

[brucemc777]

Yup, electronic climate control...!

That's what I needed to know. Ain't no shortcuts happening here, other than trying to buy a month with some Blue Devil stop-leak.

Thank-you for weighing in, I really hate chasing snipes and that would have been a mess.

 

[DonB]

Your Welcome. Sorry to be the Gloom & Doom guy here. I thought you'd like to know what to anticipate. It is do-able. It's just not going to be a quick fix. Hope the stop-leak helps, but that stuff "can" clog up a radiator too. When you get it back to Colorado, flush that stuff out before changing the core.

Keep me posted and get the FSM. It'll work out.

Best Regards, Don