Heater Core Repair

[Tank5]

I need to replace the heater core in my 91 80 series. I sourced a used unit that I have dropped off at a radiator repair shop to have it checked for leaks before installation.

What I purchased

Referencing the picture above there is a joint in the top tube on the right that is clamped at the flange and I expect uses o-rings in the slip joint to seal it. I asked the shop if they had a way to open it and replace the o-rings and they could not do that. They said they could solder the joint though to make sure it doesn’t leak. Has anyone had this joint soldered or repaired another way?

 

[cnorm5623]

I just replaced my heater core with a used. I rolled the dice and pulled it apart and replaced it with new O-ring my self. I have an O-ring kit so I just dug through till I found one that fits tight. I also put O-ring lube on it too. I think my original problem was that O ring but I didn't do a leak check on the old unit until after I pulled that joint apart.

 

[Tank5]

I just replaced my heater core with a used. I rolled the dice and pulled it apart and replaced it with new O-ring my self. I have an O-ring kit so I just dug through till I found one that fits tight. I also put O-ring lube on it too. I think my original problem was that O ring but I didn't do a leak check on the old unit until after I pulled that joint apart.

Thanks for the info. How did you resecure that joint? The flange clamped over the joint on mine looks like it is permanently attached on one side.

 

[cnorm5623]

Thanks for the info. How did you resecure that joint? The flange clamped over the joint on mine looks like it is permanently attached on one side.

its just a spring clip. well on mine it was any way. just pried on both ears and it popped off like an E clip

 

[Tank5]

its just a spring clip. well on mine it was any way. just pried on both ears and it popped off like an E clip

I will take another look at that joint. It would be better if that is a clip on mine and I can just pull it apart.

 

[Kernal]

Something that might help prevent leaks in the future is using a Gates Power Grip Heat Shrink Hose Clamp installed over that joint with the smaller metal clamp/clip.

Haven't used it myself for that application (yet) but have replaced most of the hose clamps in the engine bay of my 97 model FZJ80 with the Gates Power Grip "clamps" and they work very well.

They shrink down just like heat shrink tubing but are much thicker and can shrink around an uneven surface.

Start by measuring the OD of the clip/clamp then pick the Gates PG clamp
with the smallest ID that will slide over that (? .625" or 3/4" ?)

Gates® PowerGrip® SB Clamp | Gates Corporation

Gates hose clamps and couplings meet or exceed the toughest SAE requirements, and are engineered for the optimal fit to your existing Gates hoses and assemblies. Our fluid power products offer maximum flexibility and lead prevention on your heavy-duty applications, regardless of pressure. No...

www.gates.com

Watch some of the you tubby videos if you're curious:

https://www.youtube.com/results?search_query=gates+power+grip

 

[landtank]

I posted the O-ring specs not that long ago on another thread. I'd search for it and just replace it using the factory clip.

 

[John Young]

What I've done is just use the o-rings from a metric kit from Amazon and it seems to work fine.

About 9 USD on Amazon. Besides, I'm always using them for the AC.

The spring clip compresses the two ends of the pipe together. I was suspicious of the whole thing so what I've also done is wrap it in self-vulcanizing rubber tape. You have to be somewhat careful about adding thickness because the plastic housing of the HVAC box won't tolerate that much. I also would suggest that leaving it rotatable is a good idea. The clearance around the hole where the end comes out of the firewall is not that much so if you solder it, you may have some clearance issues.

Another thing I suggest is while you have the core out, have an additional 3-4cm of pipe braised to the inlet and the outlet. Not much of the pipe sticks out and I have found it makes a huge difference. Also the ends of used parts tend to be rather weak given passage of time and so forth, so cutting off the ends and renewing them a little longer is a really good idea.

It may not be pretty, but IMHO it is a really good idea. I used to have to ask my younger boy to climb into the engine bay to worry the hoses on--I just could not do it. Here is a link to one set of travails when it comes to heater cores. We had another in the US.

A garage owner I respect also says it is vital to roll the new ends to ensure that the heater hoses can be well-secured with clamps. I've come to really like the wire-style clamps as opposed to the helical screw clamps.

Finally, on my 80 in the US where I went through quite a journey with this I decided to put ball valves on inlet and outlet. These cores fail all the time. And if they do, you loose your coolant. Yes, the heater control valve is there, but I don't think is seals or actuates completely, and besides it only closes one side of the heater core.