Heater core clogged by mixing two Coolants

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ChristianReske

ChristianReske

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Hi all,

in a german VW forum one member facing the problem that the heater core is clogged, because "Old Green" (VW G11 - with silikat) and "New Red" (VW G 12 - without Silikat) coolant was mixed.

Is it possible do de-clog the heater core chemical?
If so, what is your recommendention?

Thanks!
 
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Mix OAT and HOAT and you'll mess things up real bad too. I'd try a CLR cooling system flush, and a forward and reverse flush of the heater core, making sure both houses are disconnected from the engine. Then I'd fill the engine with distilled water, take a drive and flush the heater core again before mixing in coolant and distilled water. I've heard of people with OAT and HOAT mixed having to replace radiators, and heater cores as a result.
 
Blow the core out with compressed air (not too much pressure), warm the bottle of Essig-Essenz in a pot of boiling water for a few min and with a funnel pour it down the heater hoses.
Let sit for about 1 hour, flush with water and repeat until its running free. I had good luck with this a few times.

 
Originally Posted By: redbone3
For those not familiar with German. This stuff is concentrated vinegar (25%).


Probably makes a heck of a cole slaw haha

In terms of the heater core you can remove the two hoses and blow it out with low PSI compressed air. There should be a bunch of crud coming out just with the air. from There you can you either vinegar as mentioned or even hot water and it should flush it pretty well. After that I would drain and flush the entire system.
 
Sis' '88 Jeep had a leaky radiator so previous owners added gooey, clay (?) leak stop products which clogged the heater core.

Strong floor cleaners didn't touch it so I used gasoline. I used short hoses run to where the heater hoses attach.

One pointed up with a funnel and the other pointed down to a catch pail.

THAT dissolved the crud like nobody's business. Kira
 
No harm in reverse flushing it, or even using a cleaner additive.

Never heard of mixing 2 normal coolants doing anything other than causing some extra corrosion.
Odds on the coolant has never been changed or tap water has been used as a top up.

Some HG sealants are real bad for clogging rad's if not used correctly.
 
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Been there done that. It will be a struggle with straight, undiluted CLR. Anything less will be pointless.

Hook up two hoses to the heater core inlet and outlet. Fix them somewhere so the point straight up. Fill both hoses with straight CLR, and let sit for 15 minutes.

REVERSE flush. Repeat, because it will likely clog back up during the flushing.

Keep doing this until you get NOTHING coming out with the CLR after letting it soak in the heater core.
 
Will this help ?

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IMG_20110819_180839.jpg
 
Originally Posted By: Bgallagher
Originally Posted By: redbone3
For those not familiar with German. This stuff is concentrated vinegar (25%).


Probably makes a heck of a cole slaw haha




That and combined with the sweet taste of antifreeze it would make a killer salad dressing.
 
Originally Posted By: Silverado12
Originally Posted By: Bgallagher
Originally Posted By: redbone3
For those not familiar with German. This stuff is concentrated vinegar (25%).


Probably makes a heck of a cole slaw haha




That and combined with the sweet taste of antifreeze it would make a killer salad dressing.


Uh huh.
wink.gif
 
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