customcruiserfan

Is there any thing to watch out for when replacing a heater core on a '71 Olds Custom Cruiser wagon (455)? Looks like a bear to do. Thanks in advance for any tricks, tips, or advice you can share.

CCFan

2blu442

I've never done one on a Custom Cruiser, but have done several on the Cultass. I like to remove the passengerside inner fender liner for better access to the firewall side of the unit.

Also plan on getting antifreeze spilling on your floorboard when you remove the underdash portion. If you have an air compressor you might try blowing air through the hoses before taking things apart. But I've always ended up with a spill. If you've got plastic sheeting and absorbent rags ready that might help.

It is a bear to do, but if you don't get in a hurry I don't think you'll have any problems with it.

The search option here isn't always the most user friendly, but if you have time to read through some old posts I know this has been discussed before.

John

jfb

I helped someone do one a 74 custom cruiser once it was my dads car and i have a 71 cutlass now both 455,s also it is no different then any other cutlass just do it correctly and check the new one for leaks before installing or i mean pressurize it beforehand. do not forget a new gasket for the box and flush your system also before filling it.

m455sx

i replaced the heater in my 442, it was a pain in the butt. i did not remove an inner fender but i did it in a full day and it included cleaning and lubing everything back up. Funny thing was Advance auto said the A/C heater was discontinued on the 442.... So i told him to search Chevelle SS and what surprise they had one in stock! Perfect fit!

matt69olds

If you don't mind making some permanent modification to your car there is a easy way to "cheat" and make the heater case much easier to remove. From inside the car look at the heater case. This is the stud that requires removing the inner wheel house to remove the nut on that stud. Find the dimple where the lower stud is fitted to the case. Use a drill bit and drill the center of the stud. The idea is to drill the center of the stud so it falls out of the heater case with the nut still attached. Once that is out of the way, you can access all the other bolts, they aren't easy yo remove but can be done. There are about 10 studs that hold the case to the firewall, I'm pretty sure leaving one off wont hurt anything.

customcruiserfan

This really helps a lot. Thanks for the replies, guys.

Lady72nRob71

3M 'strip calk' is used to seal the box up again rather than any special gasket.
Here is a writeup on replacing the core in a 72 Cutlass with 350 and AC.
https://classicoldsmobile.com/forums...tml#post362172
Yours will be different of course, but it might give you a few hints...