DUDE454

Ve tried the search and if this post exists already I'm sorry. How can I flush the coolant system on my 01 XJ 4.0? I herd someone say take a hose and hook us to put water through the system until it is clean. I've never done it so I'm not too sure what to do.

Radi

I normally remove the upper radiator hose from the thermostat housing, remove the housing and thermostat and set it aside. Then stuff a garden hose into the upper radiator hose as far as it will go, use a vice-grips to gently pinch the upper hose so it seals around the garden hose somewhat... radiator cap on, heater control set to "hot", and let 'er rip.

If you decide to use one of those plastic T-fittings in the heater hose, remove it when you are done and replace it with with metal tubing and two clamps. Those plastic fittings eventually leak.

markbradleyf1

Thats the best way to do it! Recommended!

ZINGGG

You can also flush the block out by removing both the thermostat housing and water pump and putting the hose in the thermostat housing hole

djb383

'96 is spot on.......and if u remove only the top rad and stick a garden hose in it, any/all loose crud from the radiator will be flushed into the block/head.....not good. Sounds like flush-up to me and crap don't flush up. LOL

ZINGGG

Hahahaha love it.

So to prevent this from happening, aren't you able to remove the lower radiator hose from the water pump? I'd think that'd be a good way to get some crap outta the radiator.

Radi

Good point. If there's that much crud in the system, probably best to flush the block separately from the radiator. Keeps radiator crud out of the block, and block crud out of the radiator passages.

DFlintstone

Oh..I don't have any special insight here. Just wanted to mention that I saw suggested somewhere you if pull the bottom radiator hose you can flush the bottom crud better, seems to make some sense. The same guy pointed out that the drain **** can be nearly worthless, or worse, crud jets stuck in it. I'd do the heater separate myself.

cpnwrench

:smokin:

Ok, all good data here guys!

here is what I do when I clean out my cooling system

Yes, it is tedious, but then I don't have to worry about it for a VERY long time after.....

I remove the radiator from the Jeep. then flush the block (as described on this thread), then I flush the heater core separate from teh engine and radiator, then I flush the radiator using high pressure water mixed with simple green, then re-flush with high pressure water.

After its all dried out (leave out in HOT sun for a couple hours, enjoy cold beverage in lawn chair, yell at neighborhood kids riding bikes into your yard, ogle next door neighbor in the garden),,,,,,
then I use compressed air to blow out any residue.

Then after re-assembly, I use 50-50 Distilled water and Prestone.

Coolant will stay nice for at least three years. I have done this at least 7 times since I owned 'Ol Red and it has worked VERY well for me.

however, to each his own........

good luck!

cpnwrench

:smokin:

djb383

Yep, remove bottom rad hose from the water pump, remove the top rad hose and heater hose from the stat cover and remove the heater hose from the pump. Stick the garden hose in either heater hose, then in the heater hose nipple on the stat cover, then in the top rad hose. This will prevent a flush-up.

......and be safe/kind to kids and animals.

cmarr6

Are you guys using any coolant system/rad flush products first? or just flush with straight water? I am going to do this this weekend. '91 limited is running at 220. Need to do some preventative maintenance.

djb383

I just used straight tap water from the garden hose.

Decemberist

Lol, with you on everything except the ogle the lady next door...Only because she weighs 250lbs.

BigBear

To flush the entire system it is best not remove any hoses and just open the drain on your radiator and if you can the engine block drain plug.

I flushed my 89' system from the pressure bottle and drained from the raidator drain.
You do not need to run the engine at this time but keep the water going into the system, it will fill the engine block and go through the radiator hoses and out the drain(s).

This is after you flush it with preston flush kit while running.

Trust me I know what I am doin I just tested my new cooling system with just water on a 93f day for 30 minute idle and some slow driving and it never past 210.

Make sure you have 3.5 gallons of mixture in there or you will still over heat no matter what your setup.

Delta

100 degree weather on just water I'm Miami gridlock with out electric fan and my old Cooling system wouldn't touch 210. That's with a proper tstat and a laser temp gun. If you don't have a new radiator it's best to just remove the lower radiator hose the petcocks like to get brittle and break