Best JB Weld product to patch broken plastic heater core pipe
 

1995 Isuzu Rodeo 3.2L V6

Plastic heater core pipe broken off, but for the most part, still intact.

Will insert a Dorman plastic hose pipe into the broken heater core pipe; then seal with a JB Weld product.

Dorman Products - 47081

Looks like the better choices would be as follows(traditional JB Weld does not adhere well to plastic as per their web site):

JB Weld PlasticWeld

JB Weld WaterWeld

Both are likely capable of sealing moisture(coolant) and withstanding it's heat.

homedepot.com touts JB Weld Kwik for such a project, yet I don't see a matching product description at the jbweld.com site. Seems like JB Weld Kwik is just a faster setting/curing version of their original product?

Which would you choose or would you think something else is better?

Thanks for your time.

I once cooked a headgasket and blew out a radiator. I patched it with a piece of sheetmetal and plain, regular JB weld.

I would just go with the regular JB weld, try to get your two pipes to fit as close as possible. Rough up the surface with a pocket knife. If you can, wrap/place some wire in there to act like rebar under the JB weld.

Most important for adhesion:
Gouge/rough up the surfaces
Clean with alcohol
Dry the mocked up assembly with a hair drier
Allow the JB to setup up over 48 hours, in a warm (70*F+) area before putting it in service

Thanks for your reply, but I'm dealing with plastic; not metal. For your situation the traditional product was the way to go.

you can buy plastic radiator tank repair kits from autozone, napa etc, it comes with a fibreglass cloth and piece of rough sandpaper too.

The putty is two piece and exothermic, it gets scalding hot - so be careful - sandpaper it rough, cut cloth to patch size, mix hardner and activator - apply and let it set, the heat melts the fiberglas and bonds it to the plastic.

^that is what I have had the most luck with.

I've had good results with replacing heater cores. Everything else, not so much.

MV

Cannot recommend JB Weld for a plastic radiator/heater core repair, even with a sleeve insert. It just doesn't seem to last under the heat and pressures involved.

Thanks to all for your input. I decided to call JB Weld at their company HQ in Sulphur Springs Tx. 903-885-7696

Described my situation to them. Was told to use their High Heat Putty Stick:

HighHeat | Temperature Resistant Epoxy Putty

I like epoxy resin and cloth for repairs like that.

A common issue for the 300d ,sd,cd td radiators is the weee little nipple return pressure hose from the reservior tends to crack off leaving you with just a open hole were the weee little nipple use to be ,hint, under built.My answer for this was found at the fix it isle of bolts and nuts at the local auto parts house.The part has threads on one side with a nipple on the other.I drill out the hole were the weee little nipple was and screw in the metal replacement ,you want to under drill this hole size of coarse.The other detail is that the radiator will have to be out of the car for reasons of the epoxy application, the radiator is tilted just so to allow for the epoxy to surround the new mighty metal nipple as the replacement,the nice design feature in these radiators is that craddle area around the nipple which is perfect for pouring epoxy into as long as the radiator is at a certain tilted angle in my description,you dont want too much or the hose wont fit back onto the new nipple ,just enough to supply the new part with plenty of support and leak protection.I use the black 2 mix epoxt product .

When it was all said and done, the following product fixed the problem. All other products bounced off the heater core plastic pipes like a rubber ball.

Plastic Bonder Syringe | J-B Weld

if its a plastic radiator tank,,,,
unless you fix whatever caused the unusual pressure situation, it'll just crack again next to the repair

How about classic epoxy?

Even after prepping the surface, the temperature, pressure, vibration and expansion/contraction will cause epoxy to fail. I've often wondered if "plastic welding" would work, but while great for bumper shells, probably wouldn't do will under pressure.

Q-Bond works awesome
 

Q-Bond — Quick Bonding Ultra Strong Adhesive and Filling Powders

amazing stuff, saw it at a NAPA parts store counter. Not cheap....but you know what they say....you get what you pay for.

Used it on a '82 Volvo 245 GLT driver door map pocket. Works good.