breathial

While stop-leak may (and often does) solve the problem, it also introduces long-term problems, as Gusto has mentioned.

It coats the entire cooling system- radiator, heater core, block coolant passages... everywhere. I've even seen it (temporarily) solve head-gasket leaks...

BUT... The very fact that it coats the inside of the entire cooling system, is also the problem. The coating inside the radiator slows the rate of heat transfer, making the radiator less efficient, and reduces the cooling capacity of it. The engine sees the same effect, and more heat stays in the block, instead of being dumped like it is supposed to be...

IF you were planning on selling the car, and didn't want to spend any more money then necessary to roll it down the road, then I'd understand it (though I do NOT agree with said practice). People do this sort of thing all the time...

But if you're keeping it...? If you want to prevent problems from cropping up, from using this stuff....? Then by-pass the heater core, order up a new one... And take a Saturday afternoon to fix it...

Just my $.02.

74 vert

I agree, replace the heater core or bypass. Be aware where you buy the core. I recently replaced a core in the 96Z28 with a Autozone part, and later developed a leak; bad new core. Pay the extra $$ and get a GM heater core, not something from a discount auto store.

Hwy St*r

OK, if I added the votes right as tempting as dumping some stop leak in the radiator sounds I'll be doing a bypass this weekend. What are hose sizes that need to be coupled together? What size piece of copper tubing do I need to use? aren't there hose clamps already on the ends of the hoses holding it to the heater core? Lastly, How well will my defroster work without heat (it is a daily driver year round in NJ)?

Jay M

My heater core just broke a few weeks ago on the way to work, so I had to do a quick fix in the parking lot. On my car '68 BB, there are two hoses, one big and one small. I don't remember the sizes. I was able to attach the biger hose directly from the water pump to the intake. I just tightened the hose clamp real good and it doesn't leak. The smaller hose can be removed.

~Jay

GUSTO14

5/8" & 3/4"... You might find a PVC coupler that fits this at you local Home Depot, look in the "outdoor sprinkler" section. Otherwise a short length of at least 5/8" OD tubing can be made to work.

Unfortunately the ole defroster an't gonna work too well without some heat... just don't sing too much while you're driving to work...

GUSTO

James1970

This is not good news. I replaced my heater core with one from Autozone ~$50.00 last April. I noted it was made in Mexico but still installed it although alarm bells were going off in my head.

The new core has only about 1 hour of use on it as I drove the car to the paint shop after installing. Wonder how long it will last once I start driving the car consistently???????

PS: I miss "Made In The U.S.A."

The_Dude

I had two heater cores go bad on me in the last year (both rustangs). Alumiseal prevented the windshields from fogging up and allowed me to use the heater until I could take the time to replace the heater cores. It's certainly not a permanent fix, but might buy you some time.
I agree with others about Bars leak and those types of products. They can cause more problems than they solve. Bars settled in the bottom of radiator of an old truck I had and no coolant would flow until the ambient temperature warmed up.

BKbroiler

You don't need a bypass. Buy 2 plugs at Home Depot, one for the water pump and one for the intake manifold. I did it this way 3 years ago - no problems. There is enough heat to be comfortable to the low 40's. No defroster however.

nutben

nutben

that's works to

Alan 71

Hi,
I can't even remember back as far as October, 2005.
Regards,
Alan

rcread

Yeah, I'd imagine he got a new heater core by now.

Paul L

I've had two.

yyz1970

if you are avoiding the repair the core can be bypassed easily until you replace it

gbrewer4601

I will never use the coolant leak products ever again, They will block passages in radiator, restrict cooling of engine block passages and cause engine failure because of excessive heat build up. The heater core fails because of corrosion from incorrect fluids in radiator. Do not use tap water added to antifreeze. The chemicals in tap water cause a reaction to the metals in the cooling system. The resulting corrosion of the radiator or heater core are the because of the chemical reaction. Best thing to do when changing or adding antifreeze is to buy correct antifreeze and distilled water, make a 50 50 solution mix. Why buy the 50/50 mix from antifreeze companies. If you mix yourself you will save several dollars since one gallon of antifreeze and one gallon of distilled water cost lest than two gallons of 50/50 premixed antifreeze.