heater core tube crimp - OK to reuse?

[Randall K.]

Found this when I removed my heater core from my '72. Is this normal?

The crimp looks too "perfect" to be damage from overtightening a hose clamp. I've never seen evidence of leaks, but wonder if I should reuse it, or get a new one.

Thanks
Randy

[Chris E.]

Re: heater core tube crimp - OK to reuse?

I'd get a new core. The thought of coolant all over the interior of the car doesn't sit well with me. The heater core isn't judged because you can't see it. I'd go for "function" over "form" on this one.

Just my $0.02

[Terry M.]

Re: heater core tube crimp - OK to reuse?

My 1970 is just like that.

The folks at Wittek told me the biggest problem with their tower style clamps was over tightening at the assembly plant. To that end they carefully controlled the diameter of the tightening screw so that it (the screw) would shear before the clamp crushed the tube. Obviously that didn't happen in the case of our cars.

FWIW: I put the original heater hose and clamp back on, and drove the car for the Founder's Award. It HAS been a trailer Queen since then, however. The heater core has never been out.

[Chuck S.]

Re: heater core tube crimp - OK to reuse?

...wonder if I should reuse it, or get a new one...

I can't see well, but I assume by "crimp" you're describing the depression in the 5/8" hose tube where water has pooled in the past.

I wouldn't call this a crimp from what I can see in the picture...a crimp is where the material is bent sharply until it yields completely along a straight line; one more bend after crimping, and soft materials like brass or copper will generally result in a break in the wall of the tube.

My approach would be to examine the "bottom" of the depression for a telltale sharp line or crack. Dye penetrant test kits are available from auto supply stores if you want to go that far. Of course, if the tube is cracked , it's game over...buy a new one. Or, if you really want to keep the original core, a crack in that location could easily be solder repaired. Leaks at the hose connections are less of a concern than leaks in the core itself since the hose connections are outside the firewall in the engine compartment.

Even if there is NO crack, just a straight sharp crimp line in the bottom of the depression, I would still retire (or repair) the core for the reason given above...a little too much tightening in the future, and you could have a crack. However, if the bottom of the depression is smooth and well-rounded, I would reuse the core without worrying.

[Peter J.]

Re: heater core tube crimp - OK to reuse?

Randall, I have two Harrison 66 cores and two repops. Originals are crimped like yours and repops are not. I had my original core cleaned and pressure tested by a guy in the radiator business for over thirty years and he said if it were him, he would use the Harrison that came in the my car. He did not like the quality of the chinese core. My problem with the repop was, it was almost 3/8 of an inch thinner and that made attaching the bracket interesting.
I might have a leak two days after start up, but that is what I did.

[Jim T.]

Re: heater core tube crimp - OK to reuse?

Randall I still have the original one from my 70 that was leaking into the car several years ago. If I can find it, I will take a look at it and see if it has the same appearence on the tube you have in question. I think mine looked just like yours.
If your core is not leaking, I would not go through the work involved just to change it out because it could leak later.
My 68's original heater core is still not leaking the last time I looked.

[Joe L.]

Re: heater core tube crimp - OK to reuse?

Found this when I removed my heater core from my '72. Is this normal?

The crimp looks too "perfect" to be damage from overtightening a hose clamp. I've never seen evidence of leaks, but wonder if I should reuse it, or get a new one.

Thanks
Randy

Randy-----


Given the difficulty in removing and replacing a heater core, there is no way in the world that I would re-use this core. Even if it didn't have the damage to the tube, I'd replace it. I've replaced the heater core 3 times in my 1969 since it was new and I've always perfectly maintained the cooling system.

The replacements are configured a little differently than the originals but adapting them to fit is not very difficult. Once installed, no one will know the difference.

The last Delco core I purchased was made in USA. However, the Delco piece for non C-60 C3's is now GM-discontinued.

[Peter J.]

Re: heater core tube crimp - OK to reuse?

Joe, It's not a big difference but the original Harrison inlet and outlet tubes were brass and the repops are a zinc coated metal. If your hoses are pushed all the way up to the firewall you can't see the tubes but if you don't it is quite easy to see the difference.

[Joe L.]

Re: heater core tube crimp - OK to reuse?

Joe, It's not a big difference but the original Harrison inlet and outlet tubes were brass and the repops are a zinc coated metal. If your hoses are pushed all the way up to the firewall you can't see the tubes but if you don't it is quite easy to see the difference.

Peter-----


The last Delco I purchased did not have zinc-coated tubes.

[Peter J.]

Re: heater core tube crimp - OK to reuse?

Joe,
I have ordered two from two different well know Corvette parts suppliers and they were the same zinc tubes and looked like crap. I assumed that there was only one manufacturer of these cores - so I quit looking. If anybody bought one with the brass inlet & outlet tubes lately, please let me know your source. My radiator guy said he would transplant the tubes for me but he did not like the repop at all.
Thanks

[Don L.]

Re: heater core tube crimp - OK to reuse?

For what it's worth, I have to share a success I had this spring when changing out my water pump, heater hoses, temp sending switch, all to bring to NCRS correct. This tip is irrespective of whether or not you replace or re-use the original core.

I applied a coating of Permatex item # 80062 High Tack Gasket Sealant to the inside surface of the heater hoses (approx 1 inch in) and to the outside of each core tube. I let the sealant dry to tackiness, then slid the hoses onto the tubes. The sealant, although a bit tacky, served well as a lubricant, enabling me to get those @#$% hoses ALL the way on each tube. A little torquing of the tower clamp and that part of the job was done. The sealant is totally concealed by the hoses, therefore undetectable when judged. Crossing my fingers and hoping that there were no leaks in my work, I was happy to see that all joints, including/especially the core connections were completely dry when I started the engine.

Now I'm sure that when I need to replace these hoses I'll need a utility knife and some solvent to ready the tubes for the next round, but it'll be well worth it, especially when considering it'll likely be my heirs, not me that has to do it!

[Jephrey S.]

Re: heater core tube crimp - OK to reuse?

My heater core tubes also looked similar when removed.

Take a good look at the tube surfaces and then think about what the interior of the core looks like. Even if it pressure tests fine, it has had over 35 years to rot internally. This is especially true if the car spends lots of time not being driven. It is a big job to change the heater core, not to mention the possible damage to the carpet if you do not notice a leak in time.

I bought a replacement from NAPA and had no problems. I would suggest you change the heater core and store the original in your growing pile of "stuff I pulled off but don't want to throw away, just in case" if you think that you may want it in the future. I actually threw my original away for a change.

You have already done most of the difficult work. Now the only hard part is getting that inboard nut started on the mount bracket (unless you have a 3 year old with small hands and mechanical skills to help you) and the rest is cake.

[Randall K.]

Re: heater core tube crimp - OK to reuse?

Jephry - I too thought that I have done the hardest work. However...

How do I get the heater core out of the core box? I've removed the core tube clamps and the 4 screws that hold the sheet metal cover to the housing, but it doesn't budge. The AIM and service manual are no help.

Also - I'm not familiar (yet) with the inboard nut you referred to. Where is it?

Thanks
Randy

[Jephrey S.]

Re: heater core tube crimp - OK to reuse?

Oh my, I REALLY hate to be the one to tell you this. When you said that you had removed the heater core, I thought that it was already completely out of the car.

Removing the fan housing from the front of the firewall is simple to get access to the heater core. Disassembly (for a 70, 72 should at most be very close) to remove the heater core starts at the emergency brake console and works its way forward. Eventually, after the air ducts have been pulled from the passenger side dash, the heater core is removed rearward into the passenger compartment. I was able to accomplish this without removing the radio, but it would have been less total work to have removed the radio than what it took to get the ducts properly reconnected afterwards. It is almost as if the instructions were there for a reason.

The fact that it is such a hassle to get out is a major reason I recommended replacing it since it was already out. If GM had the studs sticking through slots in the firewall instead of the holes, changing the heater core would take a total of a lazy hour. And most of that time would be spent cleaning the old sealant from the back of the fan housing.

I think the procedure is in the service manual for the 70, but it might not be in the 72 manual. I'll look when I get home and give you what my manual says.

The lower, inboard stud was a nightmare for me to get the nut started on as I recall. I spent almost an hour getting just that one nut on.

Edit: And, most important, if only the fan box has been removed, and the heater core is currently not leaking, I would definately just put the box and hoses back on and keep using it.

[Randall K.]

Re: heater core tube crimp - OK to reuse?

Hi Jephrey - my bad... I wasn't clear - I do have the heater core box out already. I was just having an issue getting the actual core out of the core box - which I figured out last night. Missed that last screw on one of the brackets on the side of the core box itself.

Maybe I'm lucky or just a masochist, but I've removed the entire heat and AC assemblies without too much difficulty. I was expecting worse given the tone of a lot of the posts! Of course, there is the reassembly of the whole system... I might change my attitude in another month!

Both cores out today for pressure testing and repair if possible/necessary.

Now ready to clean up and rebuild - already have my seal kit from the Doc.

Thanks
Randy