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Coolant Flush

Posted: Tue Aug 02, 2022 7:53 am
by tobyw
What experience have you all had with the various potions and concoctions out there for coolant system flushing? The boy's XJ has some pretty nasty looking stuff running around the system, looks like mud so it's probably corrosion/rust that needs significant cleansing as a starting point to get it fixed properly... Is the Prestone stuff even worth the $7, or is there a stronger version that works mobetta?

Re: Coolant Flush

Posted: Tue Aug 02, 2022 3:53 pm
by Lurch
How thorough do you want to be? This is the procedure I use for flushing diesel cooling systems that are pretty bad.

You'll want to do this in a gravel driveway. Or over a drain. It gets messy.

Completely drain the system. Remove the thermostat and reinstall housing without the t-stat in it. Dump a gallon of simple green in the radiator. In your case probably a half gallon would be sufficient.
Run engine at about 1100 rpm till it's warm. May have to throw cardboard in front of the radiator.
Open the petcock on the radiator and stick a garden hose in the radiator. You want enough water flow to get water coming out the top of the radio for and the petcock both at the same time. Continue running engine while flushing with water. Do this till you have clear water running out. I typically repeat the procedure a second time. Also run the heater while doing it. Then replace the t-stat and ad coolant. Keep in mind it will have straight water in the engine so mix the coolant accordingly.

Re: Coolant Flush

Posted: Wed Aug 03, 2022 6:09 am
by tobyw
Thanks Tim, I'll give Simple Green a shot!

Re: Coolant Flush

Posted: Wed Aug 03, 2022 6:33 pm
by SPR
Why Simple Green? Is it a ph or detergent thing?

Re: Coolant Flush

Posted: Wed Aug 03, 2022 6:44 pm
by Lurch
A little of both. Plus it's eco friendly. So when you drain it in the gravel you don't hurt anything.

Re: Coolant Flush

Posted: Tue Sep 13, 2022 6:31 am
by tobyw
Just to follow back up on this, I used Simple Green and ended up finding that it didn't do exactly what I was hoping for. That is NO fault of the Simple Green, however... turns out I was battling a blown head gasket that was constantly stirring up crud and causing more corrosion :oops: Good times for sure.

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Re: Coolant Flush

Posted: Tue Sep 13, 2022 12:24 pm
by Roman
Might as well put a cam in it while its apart...

:lol2