Flushing Heater Core/Engine Block

[Jay in Gray]

Hey guys,

Any tips on flushing old coolant out of the heater core and engine block? I am replacing my rad, water pump, thermostat and heater hoses (and a few other things) and wanted to make sure I get everything out. I have read the articles that Chris posted (thank you for that and the links to the parts...purchased all OEM) and ready to tackle the job but just want to make sure I get all the old out.

Thanks in advance for the help!

 

[Jay in Gray]

Just a bump for any tips. Thanks

 

[Chris]

Best tip you'll ever get: USE DISTILLED WATER TO FLUSH THE SYSTEM!

Go to your local grocery store and buy distilled water (2 gallons of it). It's about 89 cents per gallon.

If you use anything but distilled water (i.e. tap water) it will have minerals in the water. The minerals will hang around in your cooling system and cause it to rust. A year or so from now, you'll remove your radiator cap and find brown gunk floating around in there from all the rust. This is even more important if you live in a place with hard water (i.e. Arizona), where the tap water is just overflowing with minerals in it!

So yeah, when you're flushing it, dump those gallons of distilled water through it to flush the system. Your cooling system (and your wallet) will thank me in the meantime.

 

[Jerry Bransford]

To Chris's good advice on insuring your cooling system only ever sees distilled water, I'll advise to avoid aftermarket/store brand water pumps and radiators. They just don't hold up, and it'd be real hard to find an aftermarket radiator that will cool as well as the OE radiator does in all conditions like my local hot deserts. Really. I have a LOT of aftermarket parts on my TJ but my cooling system will stay 100% as the factory designed it. Also avoid installing a "failsafe" thermostat which tends to fail in the open position. A good quality 195 degree thermostat like Stant's SuperStat is what you want. Zerex G-05 would be a very good choice of coolant, you can find it in better auto parts stores like NAPA. Low-end auto parts stores like Autozone don't typically carry the good stuff like G-05.

 

[StG58]

Just did an OEM radiator on my TJ. The buildup of brown crap in the hoses and other parts was amazing! I did an extensive chemical flush, but it didn't get all of it. It's something that will need to be done several more times with harsher chemicals, to clean it all out. Like @Jerry Bransford and @Chris are saying: Use distilled water and Zerex G-05. Plan on spending some time at it to get it right the first time. It took me about 15 minutes to actually change the radiator out, but three hours to attempt flushing the system. It's still not clean all the way through.

 

[Jay in Gray]

Thanks guys. I plan on installing all new Mopar parts. Rad, Water pump, Thermostat housing and coolant. Stant thermostat and gates hoses. Thank you @Chris for listing the part numbers in a previous thread. Saved me alot of time !
I think I may have done a bad job of asking my question, and it may be a dumb one so please forgive me. But when i take the rad, water pump and thermostat housing out as well as the heater hoses is there a good (and preferably easy) way of making sure all the old coolant is out?

 

[Jay in Gray]

Thank you as well Jerry for your advice. Reading some of your post and seeing that if the Mopar radiators can make in the Cal. desert they can definitely survive the GA heat and humidity !