I need to replace the Heater Core in my 1972 Oldsmobile 442 W-30. Any idea what the easiest way to do this is? I heard the fender has to removed, is it true & if so, what's the best & easiest way to accomplish this the least painful way? Thanks, Brian

Car Does NOT have A/C.

 

There is not a "hard" way and and "easy" way. There is only one way, and that is to get yourself a copy of the factory service manual for your car and follow the directions in it.

Replacing the heater core usually involves either taking much of the passenger side dashboard apart if the route to it is from the passenger compartment, or removing a cover over it on the firewall if getting at it is done from the engine side. Sometimes removing the cover requires drilling a hole through the passenger side inner wheel well to get at one of the hold-down bolts. This is why having the manual is so important as the procedure can vary from car to car.

With all of those Oldsmobiles in your possession, have you never had occasion to buy a service manual?

 

My car being a W-30 was not optioned with A/C. It was not available. Thank you for your post & information.

 

I'm curious what manual you're looking at. Page 1-17 of the chassis service manual, available for free at wildaboutcars.com, has instructions on how to remove the heater core. It is located within and attached to the heater case. There are five attaching nuts holding the heater case against the firewall. Four are accessible, but, as I suspected and mentioned above, to get at the fifth one, it will be necessary to "disconnect the right fender at the bottom and block away from body." In other words, you do have to do some slight disassembly of the right front of the car to get at one of the nuts.

Then you'll want to look at Figure 1-30 on page 1-18 as it shows how to remove the heater core from the heater case you've just removed.

 

The factory CSM was useless. It just said "the heater core can be removed after the heater case is removed from the firewall as shown in figure x" and they showed a non-detailed picture.

The A/C heater case has 4 nuts on the engine side and 2 bolts on the inside.
I had made my first instruction post as a shot in the dark, since the OP did not indicate with or without A/C.
Now that we know it is non-A/C, I deleted that missed shot.
I do not know details on replacing a core in a non-A/C car, nor do I know how many nuts and bolts hold it in. Hopefully someone else who has done this will chime in with their adventure...

 

I've replaced the heater core on my '72 twice in 20 years . Pain in the a*s? I'd say so. I didn't have to remove the fender but I did have to detach the inner fender well and push it out of the way. By comparison i replaced the heater core in a '70 Cutlass, 350 and no A/C, and that was a breeze.

 

I've never done it, but I understand that, most times, getting at the heater core is not for the faint of heart. That's good to know that you didn't actually have to loosen the fender itself, which is what the manual says, to get at that last nut.

 

Thanks for the info. I guess this will be put off until snow flies here in Massachusetts, no need for heat right now anyway, it's like 82 degree's today. Really don't need to fix it but I'm ****, I like things right so it's going to bug me until it's been replaced.

BTW - Nice Green 72 442 Joe.

 

Remove the passanger seat 4 nuts on the firewall 2 inside. And expect to buy new defroster hoses. It helps to remove the center console also for putting it back in. Also remove the heater linkage from the top of the box cover. And don't forget to blow all the coolant out of the core before pulling it out

 

And you'll want a working heater on a hot day when it wants to overheat in traffic. Take about three hours. But I still don't have the defroster hoses hooked back up. Its not as bad as it sounds

 

If you've never done a job why on earth would you give advice on how to do it? I'll never understand.

I just pulled all of mine out. You just take out the bolts holding the passenger side fender well in. It should be 4 on the fender, 3 on the frame of the car, and 2-4 on the front by the right front headlight. Once that is done, push the fender well up to get it off of the lip of the fender and then allow it to drop down onto the wheel. Once you've done that you can get to everything you need to. Loosen the nuts on the firewall and then remove the screws from inside the cab. Disconnect the linkage from the box and then remove. As you remove it, roll the top towards the inside of the car and whatever fluid is still in it will not spill out.

Heater cores are really easy to get to once you've done it once or twice. You shouldn't have a problem.

 

You can get to the lower ones on the firewall by just removing the back two inner fender bolts. And a ratcheting box wrench. And use the old spacer off the core for the inlet outlet new ones normally wont have it. But I've never done this so who knows and unless you're a midget take the seat out.

 

I wasn't saying you've never done this...I read above where Jaunty was saying to pull the fender and all kinds of stuff, and then mentioned he'd never done it himself. Good call on the seat, for buckets it makes it so much easier when you can lay down in the car.

 

No worries its not a fun job to do, but it can be done. Mine decided to die right after I just painted the fenders and put everything back on.... The bracket's is what kills the cores. I put some foam tape in the bracket's to soften the bumps.

 

Got the job done over 2012/13 winter. Had to remove Right Fender. Easy job once that was out of the way. Came out through engine bay.

 

I have heard, that many GM techs in the day would drill out the one hard to get to stud from the passenger compartment. That way they did not bother with the fender or the inner fender. No it's not "correct", but those guys were working against the clock.

I replaced my heater core back in 1975 or 76 by loosening the inner fender, and reaching in from the bottom to access the nut. If I had to do it today, the drill would come out.