1969 GS 400 Heater Core

[BGS400]

I need some guidance on replacing my heater core. I know I have to remove it from the engine side of the firewall, but how do I get to corner bolt that is blocked by the inner fender?

Any help or guidance will be appreciated.

[Bob]

That is not just a problem with the '69! Those nuts are rarely replaced after a core change because of access. You can thank the engineers for that.

[carmantx]

The heater core is in the passenger compartment. It is not that hard to pull, compared to the blower motor. You do have several bolt/nuts on the engine side, but you pull it out under the dash. Still not an easy day of work though.

This should be helpful.

http://www.buickperformanceclub.com/heatercore.htm

[BGS400]

Thanks for the info. I knew it wasn't going to be easy. The website should be helpful though.

[ericngail]

I am not sure if this will help, but it can't hurt. It looks to me that there are only 4 nuts that have to be removed from under the hood. They fasten to studs that are attached to the heater box under the dash. Then there are 2 sheet metal screws that screw to the firewall from the inside.

The 4 studs that are secured with nuts are exposed without removing the HVAC cover under the hood. 3 of them aren't too hard to get to, but the lower one closest to the passenger door will be quite a task. Lying on the ground, looking straight up between the inner fender and firewall, I can see it on my car (69 GS400). I imagine that removing all of the bolts for the inner fender will give me enough room to fit a hand and wrench up there.

Here is a picture, if you can zoom in, I have the nuts marked with arrows.

pic 1.jpg
HTH, let us know how this job goes.

Eric