Gentlemen; Found green coolant where the pedals are, assume heater core shot. I understand it is an easy fix for a shop if you can just get it out. I have removed the four most obvious speed nuts on the engine side of the box, but it won't budge. Are there nuts up by the blower motor that I have missed? Aslo, the chassis manual says that I have to drill some kind of stud out on the interior side, and I don't quite get it. I also don't know what else I have to do to drop all this assembly to get at the core. Anyone who can explain it for me ( I'm not an experienced wrench ) I would appreciate it very much. Thanks for any consideration. R. B.

The car is a 69 Malibu. ( sorry about that )

On my 67 I had to take out all the heater stuff under the the hood(the first 2 hours)...Then hehe you got to take out the clove box,and all the heater \AC air duct stuff :) and the AC\heater controll flap cables...and sometihng about a midget in a clown suit...I don't know, anyway. Then you can unbolt the heater core. I took me about 4 hour just to get it out. Try not to break anything ,my air duct(stuff)was kinda brittle.

Is it with or without a/c? I did this on my non-a/c -69 Malibu last weekend and it wasn't too difficult.

There are 5 speed nuts: two on top, three at the bottom. One of the bottom ones is almost hidden behind the inner fender, but people say that you can remove it without removing the inner fender if you just use enough bad language. Maybe this is the one they tell you to drill out from the inside? I was replacing the fan so I removed the inner fender, and I didn't have a problem reaching any of the nuts.

Anyway, removing the 5 speed nuts will allow you to remove the inner heater housing, but the outer housing will still be attached to the firewall. In order to remove this, you need you need to remove the inner fender and then remove two screws around the blower.

Before you remove the inner housing, you'll have to remove the glove box. Once the housing is loose, flip it over, remove the retaining clips and you can finally remove the heater core. You don't have to remove the damper control cables, as long as you're careful not to bend or pull on them. Installation is the reversal of removal. ;)

Here's a tip: I have heard that there are many brands of heater cores to chose from and some just won't fit. I got a Ready-Aire from Autozone (part #398229, $22.99). It fits like a glove and looks just as good as the original unit. I also got a fan (Siemens #PM102, $32.99) and it looks and fits great. Again, this is for a non-a/c car.

Thanks Olle, sounds like I missed a nut and this explains why I can't shake anything loose. I have most of the nuts out of the inner fender well. Since mine is flexible ( not metal ), I was hoping to snake a hand up in there. I will go back at it tomorrow, hopefully with some success to report. R.B.

One more thing: There's a strip of sealer between the outer heater housing and the firewall. If you don't want to remove this housing, you need to be careful not to break the seal. If you do, you'll probably have to remove it and replace the seal, or you could end up with a leak. Might not be a big deal, but it could possibly leak when you wash the engine compartment etc.

It's not all that hard to remove the inner fender though, and it will also allow you to replace the blower (might be time for it to retire if you have the original blower...) and reseal the housing. Just remove the battery tray and all the screws that hold the inner fender, then you can wiggle it out.