Heater Core Questions

[BrianG]

So, I'm considering just replacing the heater core on my truck during the rebuild. I don't really want to find out later that I should have done it now. One option, is to take my old one to a radiator shop and have it checked out. The other is to just order/buy a new one. If I decide on new, I've heard that many of the new ones are aluminum instead of whatever it is they are from factory (brass, bronz, copper????). I've read some negativity toward the aluminum heater cores... so... my question is why??? I probably will hardly drive it in the cold, so if its just a little less on the heat output then I guess I don't really care. Can anyone with experience in this matter please provide some insight into this.

[Bobs68gmc]

I just put an auto zone special in mine with no worries, blows heat like nobodies business. I went ahead and replaced the blower while I was there. i wasnt impressed with the output of it though, i wonder if and ac truck gets a better blower. someone here should know.

[BrianG]

Originally Posted by Bobs68gmc

I just put an auto zone special in mine with no worries, blows heat like nobodies business. I went ahead and replaced the blower while I was there. i wasnt impressed with the output of it though, i wonder if and ac truck gets a better blower. someone here should know.

Thanks for the insight. I will probably end up replacing the blower motor also. Good to know that the Auto Zone one didn't really meet your expectations. So, was the heater core aluminum or bronze/brass... whichever they are.

[davepl]

I bought a replacement from LMC and now am seriously wishing I had taken my original one for inspection and cleaning. The factory (I assume Harrison) core is way thicker and heavier duty than the ones you buy today. I had to shim the skinny garbage one so it didn't rattle around, as it was too small for the internal brackets. It'll no doubt make heat just fine, but I don't know how long it'll last. Certainly not 40 years like the first one (assuming its an original, as it appeared to be).

I would be that AC trucks have a better blower. They have the lo/med/hi settings but actually use a relay to deliver the heavy amps needed on the high settings. Unless the non-AC trucks had that relay too I'm going to assume the AC fans took more amps.

Replacing the core can be pretty invasive. I replaced my fan and other things in there because I didn't want to have to pull fenders and so on to get back in there (I had the truck apart so it was easy in my case, but it's not normally).

[BrianG]

I have two heater cores (for two truck rebuilds). On one, the tubes are beat up and the other has come right out of the base. I would imagine that a radiator shop could braze or solder that back in, but I'm not sure what they could do with the flattened out tubes. I was surprised at how heavy those original cores are though. They really made them to last I guess. Too bad that mentality doesn't still exist from a lot of places.

[Bobs68gmc]

The autozone core bolted into place with no issues, the alignment was fine. Next time I will go the extra and mount a relay and use an ac blower motor. Air just dribbles out of the heater blower.

[BrianG]

Can anyone confirm that an AC blower motor would mount in a non AC housing... would be rather easy for me to do the same.... I plan on ordering a blower also since its all apart (and almost everything else on the truck will be new). Or, could a relay just be used on a stock non-ac motor. I assume its sort of the same issues as with the headlights... power routing through switch instead of through a relay.

[67chevy_hotrod]

My A/C truck blows hot air with a new blower motor and new OEM heater core, all the diverter doors are stuck and all the gaskets are falling apart but with just the new blower and core it works great. And honestly its really easy to replace those yourself if you are up for it. I take it you will be pulling the whole truck apart so it will be easy. I have to drop the fender and pull the hood and passenger hood hinge to do both those items. LABEL the cables when/if you pull them off and replace the gaskets. I did a 69 GMC 910 non A/C with new gaskets/core/and blower for relatively cheap. Whatever you do good luck!

[67chevy_hotrod]

Also if i where you i would replace A/C relay, Heater resistor, and the fan switch!

[BrianG]

Originally Posted by 67chevy_hotrod

My A/C truck blows hot air with a new blower motor and new OEM heater core, all the diverter doors are stuck and all the gaskets are falling apart but with just the new blower and core it works great. And honestly its really easy to replace those yourself if you are up for it. I take it you will be pulling the whole truck apart so it will be easy. I have to drop the fender and pull the hood and passenger hood hinge to do both those items. LABEL the cables when/if you pull them off and replace the gaskets. I did a 69 GMC 910 non A/C with new gaskets/core/and blower for relatively cheap. Whatever you do good luck!

This brings up a good point. ****General questions for anyone**** Is there a way, or should I be looking at anything inside the heater box. The flapper seal for instance? I see that it is riveted in there. Is the seal replaceable if I drill out the rivets?

[BrianG]

So, just a follow up, I took the heater cores to the local radiator shop. He really raved about how much better they were than aftermarket etc. He cleaned both, tested them for leaks, and ended up fixing and removing/replacing both tubes on both of my heater cores. He charged me $25 each. I don't think that's bad at all. Still cheaper than an aftermarket one, and I'm sure better as well.

I still have to figure out where to get a good blower motor though.

One final question... I see the heater core had some sort of sealant between it and the heater box. What is the best stuff to use when I put the heater cores back in? Some sort of window caulking material, or some sort of flexible plumbers putty. Or is there something better yet?

[Big John Sny]

Is the heater core steel? Just wondering if I should just pull mine and fix it.

[BrianG]

Originally Posted by Big John Sny

Is the heater core steel? Just wondering if I should just pull mine and fix it.

Nope. They are brass.

[MagmaJct]

Over the years owning two classic vehicles, a used part at the end of it's life is often still in better shape than a new one!

In a pinch, if I have to replace a used end of life part with a new low quality part, I store the used part. That way, if I come across someone who rebuilds them, or I find a method to repair it, that option is always available.