I have a '95 w/ AW4. A few months back I replaced the heater core. Before I replaced the heater core, it had already been bypassed by the PO, so it does not have the heater control valve. When I put the new heater core back in, I just used the same hoses that go in to the 97+, instead of for my year, so I didn't have to worry about the heater bypass valve. So, with that said, how would I go about flushing my system? Tomorrow, or sometime this weekend, I need to replace my water pump. I'm pretty sure I will have a lot of crap in there, since I can see that there isn't much color left in my coolant but I do see a slight rust color in the water.

 

Hook up your new hoses to the heater core and hook up a garden hose to one, blast the water and watch the crap fly out. Then do the same on the other hose to reverse the flow. My heater works 1000x better after I did this.

 

It's like a sauna in my Jeep already. LOL! I just need to replace my water pump and flush the cooling system, to get the old stuff out, before i put the new stuff in.

 

If u remove both the t-stat and water pump at the same time, u can stick a hose in the stat hole in the head and flush crud out the pump hole in the block.

The radiator can be difficult to flush completely (can't see to the bottom of the core) as the bottom half can be plugged solid while the top half flows freely giving a false impression the entire radiator is flushed and flowing freely. 1/2 of a XJ rad is not a good scenario.

Check the color of the new coolant frequently as it is likely to turn from green to brown quickly. Drain/flush/refill with new coolant as soon as the fresh green color starts to change.

 

I'd recommend one of those prestone flush kits.. Instead of cutting your heater inlet hose, just buy a foot of same size hose when you pick up the flush kit. The kit says cut the hose and insert the tee. With the extra piece, you don't have to cut the original hose. See? The reason is, if you leave the plastic tee in the heater hose, (as per the kit instructions) the tee will crack and leak over time. Not good! Other than that, follow the kit instructions. I think you'll like the ease and the results. Also, I highly recommend draining as much "tap water" out of there as you can when you're done and doin' the pump and thermostat. Distilled water is practically mandatory if you want that system to stay clean. Good luck!

 

Better yet, if you llike the convenience of using that Tee to flush things, build it yourself out of brass components from the hardware store.

Now it won't crack and leak on you.

 

Welp. Today was unsuccessful. I did manage to flush the coolant, but was not able to change out the water pump; couldn't get the bolts on the pulley to break loose. I am happy w/ the flush though. I did it w/o using the tee fitting on the heater hose. I just drained the original coolant (rusty water), filled it back up w/ the super flush and distilled water, took it for a drive w/ the heat on full blast and then drained that. Filled it back up w/ distilled water, drove it again and drained it again. then I just filled it back up w/ coolant and distilled water and called it a day.

 

U can also flush the head/block with the stat cover and water pump on by removing the bottom rad hose from the pump and removing the heater hose from the stat cover. Stick a hose in the heater hose nipple on the stat cover and flush.