Subaru coolant conditioner for heater core?

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884
Location
San Diego, CA
So, considering the potential cost/labor for fixing my heater core, I was wondering if some Subaru coolant conditioner instead? I'm actually not sure the core is bad: I have antifreeze smell when I run the heater and small amount of coolant loss but no wet floor etc.
 
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17,298
Location
OH
It would be worth a try. The R&R of the heater core is likely no joke, so if you can milk the thing along, you'd be ahead $$$ and time.
 
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19,528
Location
Lake Forest, CA
I think you should try Subaru coolant conditioner first to see if it can stop the leak somewhere, before spending big $ and/or hours to remove/reinstall heater core. Pour in the Subaru coolant conditioner in your radiator, drive the car until coolant get to operating temperature then turn on hater to max temp, dive the car for a good distance to let the sealer works its magic.
 

gathermewool

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New England
Originally Posted By: HTSS_TR
I think you should try Subaru coolant conditioner first to see if it can stop the leak somewhere, before spending big $ and/or hours to remove/reinstall heater core. Pour in the Subaru coolant conditioner in your radiator, drive the car until coolant get to operating temperature then turn on hater to max temp, dive the car for a good distance to let the sealer works its magic.
This is exactly what I would do.
 

joaks

Thread starter
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884
Location
San Diego, CA
I have a stupid question about this: can I take the antifreeze out of the radiator (to make room for the conditioner) and add to the fill bottle? I can't see why not as long as I do not overfill it (?)
 
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19,528
Location
Lake Forest, CA
Yes, you can open the radiator petcock to remove some coolant into a clean container, add the required conditioner then pour the used coolant back into the radiator to full level and pour some into the reservoir.
 
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Location
Near Mobile
So many people today don't realize that most cars unless they are several years old, don't have heater water valves anymore so putting the heater control on max is useless.
 
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19,528
Location
Lake Forest, CA
OP's car is 1997 Subaru Legacy, I'm sure it has heater control valve. When temperature is set to minimum no coolant from engine will pass through heater core, when temperature is set to maximum coolant from engine will pass through heater core at the highest rate.
 
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664
Location
Buffalo, NY
I'd say go for it, the stuff is pretty inexpensive. It's Holts Radweld from the U.K. with a Subaru label on it. If the Subaru coolant stuff finds an opening and is exposed to heat and air that's when it may plug the leak. Just suck some out the radiator cap and add the conditioner. Subaru's, at least of that era, do not have any type of heater control valve. They always pass coolant through the heater core.
 
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