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View Full Version : Clr how to


03 Rammer
01-03-2012, 11:01 AM
Just want to let you guys know that CLR works pretty well to flush out your heater cores.

*Do be careful though, to not let the CLR sit in the heater core too long or you can possibly ruin the heater core

Here is what I did: Find the 2 hoses going into the firewall to the heater core. Disconnect the 2 hoses. First flush out with water. Make sure to use a gentle stream of water and not high pressure. Once the fluid comes out clear. Then fill it up with CLR until it starts to flow out of the other hose. Let if flow out till its CLR coming out of the other hose and not water. Once it starts to flow out, stop pouring and let it sit inside the heater core for about 5-10 minutes. Do not go more than 15. Once you have let it sit long enough. Flush it out again with water using a gentle stream. Once it flows clear again and just water. Go ahead and re-connect the 2 hoses and start the truck. Now your all set to get toasty warm in your truck.

You should notice that when you first flush the coolant out. That you should see brown red coolant. First sign of a clogged heater core. Then after you let the CLR sit and flush it out, you will noticed darker brown/black fluid.

All I can say is results will vary. But the end result is that you will get heat quicker and it will be hotter.

:)