Howdy everyone,

Since it's going to feel like summer this weekend (it's going to hit 46 degrees!), I'm going to back flush the heater core. I found some videos on YouTube; it looks simple enough. I know I remove the upper hose on the t-stat housing and the hose that's the same size connected a little further back on the engine. My question is, which hose do I put the garden hose in? The one from the t-stat housing or the other hose?

Thanks

 

Flush through both hoses

 

If you look closely, you will see that both heater hoses have differetn diameters.
The larger one in the heater inlet, the other the outlet.
For reverse flushing (you want the crud flushed out, not further in), put the garden hose in the smaller one. Flush till clean water comes out, than put the garden hose in the other one, repeat a few times till happy.

 

thanks!

 

Do u still have the heater control valve?......if so, u need to bypass it to flush the heater core.

 

yea I do have the valve. that's annoying. the lines look a little short to flush after the valve.

 

hi, I have no heat in my jeep and i have never flushed it. can someone list exactly what i need to do to backflush my heater core? Do I still flush my radiator since I just changed out the whole thing this last spring? Also what is a heater control valve?

 

Mine is 1998 jeep cherokee sport 4.0

 

You're probably low on coolant. Top off your radiator and overflow tank and see if that helps. The heater control valve opens to let coolant in the heater core when you turn your heat on. Back flushing your heater core is just running water through it in the opposite direction coolant normally runs. It gets all the gunk out.

 

a 98 shouldn't have a heater control valve. i think 96 was the last year. if being low on coolant isn't your issue i could take some pics and label what hoses you should remove.

 

No control valve and no you do not have to flush the whole cooling system.

 

be careful not to apply full pressure or you can blow the core. use a "leaky connection at least to start ,. if its plugged bad you may blow it.
use a slow flow to start.
i used a piece of plastic water pipe to couple the hoses, 1/2 in