Flushing Out a Heater Core..Info

[Jack G.]

The main cause of this problem is people adding Stop Leak and keeping it in their radiator. This will cause the stop leak to settle in the heater cores.

[Terry Coombs]

Bullshit . Properly used it will not cause problems . Of course if you pour

3 bottles of Barsleaks in trying to stop up a 1/4" hole all bets are off .

[Paintedcow]

This has been a question that no one has ever been able to answer since they first made that "Stop Leak". Ask any mechanic, and you'll never get the same answer. I have always avoided it unless it was absolutely necessary. It's just a temporary fix anyhow, so I'd rather fix it properly.

I knew a guy, who was a race car builder, and he used to say you get better results shoving a few slices of white bread in the radiator. I thought he was joking, but he was serious....

[Snuffy "Hub Cap" McKinney]

I looked up the MSDS sheets on various brands of stop-leak, and most have some kind of grain ingredient.

[Vic Smith]

It easy enough to see in your overflow tank and around the rim of your radiator fill cap. I've seen it. Plenty of it when I used the GM stop-leak (which I've read is re-labeled Bar's Leak) as a preventative. It left a "greasy" residue. Probably not enough to plug up a heater core, but I stopped using it in my cars. Didn't want it in my cooling system.

[clare]

Never had that happen in 50 years.. Never seen it either.

[clare]

The white bread is temporary. A good stop leak can often last over 20 years.

[clare]

Most have Sodium Silicate, or "waterglass" as one main ingredient.

[sms]

Older cars can develop pinhole leaks in the heater core which stop leak can plug. The alternative is to bypass the heater core since no one is going to spend the money to disassemble a 20 year old car to replace the heater core.

I had this issue in a 20 year old Toyota. The leak was so small that the coolant level never moved a measurable amount, but you could still smell the coolant inside the car The mechanic suggested half a bottle of stop leak which appeared to do the trick, at least for now.

Trying to fix a radiator with stop leak is not a good plan since it's relatively easy to replace a radiator. When the plastic radiator on the

20 year old Camry cracked it was less than $200 for parts and labor for a replacement, though the genuine Toyota part would have been another $500.

[Paintedcow]

That's interesting. I thought that they contained some sort of resin that hardened, and that silver colored stuff contained aluminum powder or someting like that.

[Snuffy "Hub Cap" McKinney]

have some kind of grain ingredient.

Probably are various kinds with and without aluminum, copper, etc, depending on the application. Here's a couple of common products...

Bars MSDS... (20-25% organic material)

Brands%29.pdf

K-Seal MSDS.... (up to 7% flaxmeal)

KALK5501_SDS.pdf

[Terry Coombs]

Don't be too sure about that ... some of us prefer older cars , and I for one need heat in the winter . My pickup is 30 years old , and has had the heater core replaced within the last 2 years . I've also replaced the valve guide seals , pan gasket , valve cover and intake manifold gaskets as well as the timing gears/chain and associated seals and gaskets .

[Terry Coombs]

BZZZZT wrong again Binky . Pinholes are caused by electrolysis , which is what happens when the coolant becomes "worn out" and the Ph changes (I can't remember if it gets acidic or basic) . It must be changed on a regular basis or it becomes an electrolyte , and the resulting electrical current erodes aluminum parts . Distilled water will NOT protect your cooling system .

[>>>Ashton Crusher]

Years ago when I used to get brass radiators rebuilt I asked the guy if the alumiseal I was using was any good. He said it was ok as a stop leak but a pain in the butt for him because he needed to clean it all out before he could resolder everything. I used aluimiseal in all my cars for many years and never had anything plug up. Since most radiators went to plastic and aluminum I've found that they seem to be almost indestructible if you change the coolant every 4 years or so.

[Vic Smith]

About half the plastic radiators I've had have failed. Side cap leaks and cracks. No accidents, just some kind of plastic fatigue. GM's.

[Stormin Mormon]

My last GM (1998 Blazer) had a leak on the side of the rad.

[clare]

I've done it many times - and on cars well over 20 years old.

Stopleak won't seel a cracked plastic tank or a blown tank seal. I used to replace a lot of "O" rings and crimp plates on pastic tank/aluminum core rads - particularly the ones that used the aluminum tabs from the core end plates instead of a stainless steel crimp plate. I converted a LOT of them over the years on Toyotas. Unlike brass rads, aluminum rads generally do not fail from corrosion in 3 or

4 years.

[clare]

Irontite is full of disodium tetraborate decahydrate.- AKA Borax. Don't think that is the sealer but an anticorrosion agent.

It works pretty good too, and won't block heater cores or rads.

A lot of the good sealers only "set" when they contact air - and as long as you don't run the system low, the heater core and rad don't see air to "set" the sealer.

Some products like "BarsLea"' use sodium silicate and a fiber filler - which could be a bran or powdered cork, or some inorganic filler. Depending on the filler I suppose they COULD cause a problem if not used properly

[clare]

My pickup is 20, and if the heater core let go tomorrow, it would definitely get a heater core replaced - evan ad 340,000km

[clare]

Garbage Machines. What do you expect???