I was thinking about that this morning... how long should I leave it sit for?

 

I made an adapter out of CPVC to flush my clogged heater core with the garden hose. A female 3/4 " NPT to 3/4" CPVC pipe coupling to connect the hose. A short stub of 3/4" CPVC pipe to connect to a 3/4" to 1/2" CPVC reducer. A stub of 1/2" CPVC out of the reducer fits into the heater hose. Regular white PVC is too big, CPVC is the thinner, yellowish colored plastic pipe.

 

I just cut the end of a garden hose and shoved it in with a clamp around it and left it running... There's something in there cutting the water flow into less then half... I'm going to try and put some CLR in on Sunday to see if i can free it up... hripped open an s10 to get the heATer core out a couple years back... and with the temperatures theses days I'm really dreading having to do it again.... I'm thinking of hooking it up to the kitchen sink to get hot water threw it instead of the ground temp water....

 

Curious to see how the CLR flush turns-out. I was thinking if it would be possible to use a low volume, low pressure water pump to circulate the CLR mixture through the heater core; pump in a bucket of warm water and CLR, pump output to heater core inlet, heater core outlet back to bucket/pump inlet.
This way you could flow the heater core in both directions. Just need to find this pump...fo course the CLR would likely destroy the pump seals after awhile.

 

with the garden hose flush, run the water the opposite direction of normal flow

 

I had this problem with my jimmy when I first bought it, had to flush the core 3 times within a month because each time you free a clog it increases flow and dislodges other crap that has been stuck in there. I actually ran a garden hose into my laundry room window to use the hot faucet lol

 

Flushed the heater core... she was clogged so tight that it blew the hose right off the return... so I went back and forth from both and waited till she was clear.

so far so good after a half hour test drive, and no CLR usage at the moment.... if it clogs again I will be plowing it out and filling it with CLR to loosen whatever is left in there then flush it out.

I will also be doing a second antifreeze system flush again after my road trip