I picked up an '07 22 Supra over the weekend and am getting it all prepped for the season. I'm up north so the season is just starting - and we need our heaters...
The last owner didnt winterize the heater core properly so it was leaking, he ended up just disconnecting it for the last few seasons. It was the heatercraft 3 outlet style. I checked online and saw that you can order just the replacement heatercore which is nice, but since I had to yank out the core I wanted to see if i could either get it repaired by a rad shop or maybe even do it myself before I order a replacement. Extraction was really simple - remove 4 screws and pop off the end plate and just pull the core out.
Upon inspection 2 end loops were burst, and I could only see one other burst line close to the surface in the middle of the core. Looking at it I thought I might be able to fix it myself. I'm fairly confident that any rad shop would fix it too, but maybe at a cost close to a new core. I shined a light through the core and it didnt seem like any of the lines at the centre of the core looked burst. I wouldnt be able to tell forsure until I patched the other holes.
After looking at it there are definitely areas that are easier to repair - the end loops since they are fully exposed, and then the lines that run at the surface of the fins. If one of the lines burst near the centre of the core it would be difficult to get in there to repair. Nice thing that only a few of the lines are not close to the surface.
I picked up some JB Water Weld from an autostore - the description seemed to suggest it would work. Its a 5" round tube of epoxy type putty that you mix with your hands and apply. Its a thick sillyputty consistency so it doesnt run all over the place like liquid epoxy.
The end tube were fairly easy to apply the epoxy, except for getting in the tight spots. The tube in the middle of the core was a bit more difficult - I had to cut back some of the fins to get access to the burst tube and have a bonding surface for the epoxy.
The application went fairly well and seemed like I got a solid patch on each of the holes.
I left it cure overnight and did an old fashioned pressure blow test and it seemed to hold and not be leaking from any other spots.
I'll try testing it with some water tonight to ensure I dont have any other leaks but dont expect any since it seems to be holding air really well.
I'll try and post some pics later on. Hope this helps any other that might have a similar problem