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Radiator Coolant Flush

4

4WDlifeform

NAXJA Forum User
Location
Beaver Falls, PA
Hey guys. Planning a couple fluid changes this up comming week, and coolant is going to be one of them. I have done this before on other vehicles, but I have heard of some tricks for the XJ, like not using the drain plug, and pull the lower hose instead.

I went out and bought this:
DSC_0635.jpg


I have used this kit on a previous rig, and it seemed to work nicely.

Any other tips that some of you experianced folk would recommend? I have never done this on an XJ. Mine is a 97, sport with the 4.0.

I have also seen mentioned on here to use a cleaner, and run around with that in the system for a while? If some one could please enlighten me on this, like, what to use, how to use it... I would greatly appriciate it! I have never ran a cleaner in a coolant system before, so that is completely new to me. Thanks a ton!
 
Use a good commercial flush product. Depending on the history of the cooling system, you should use the short 15 minute product, or you may want to use the more aggressive 500 mile product.

Put the "T" from the kit into the heater hose that runs from the heater core to the WP, not the one that runs from the core to the thermostat housing--best to flush the heater core backwards to normal flow.

Yes, don't mess with the radiator drain petcock ESPECIALLY if you have the plastic tank radiator. If you have an all metal radiator then the drain petcock should be Ok, however, pulling the lower hose from the radiator and letting it drain into a bucket is easier.

Are you replacing the WP or thermostat? Life of a WP 4~5 years. If you do the thermostat I only recommend and install the Stant SuperStat Premium, 195 degree for the XJ 4.0 engine.
 
96XJ_4.0 said:
Would switching to a 185 degree do any good?
Click to expand...

For what?

If your engine is overheating it will overheat with most any thermostat, or even with no thermostat.

If you are overheating locate the source of the problem and make the necessary repairs.

The 4.0 in the XJ is setup to run at approximately 205~210 degrees as "normal" operating temperature. All a lower thermostat will do is keep the engine colder a little longer.
 
I don't usually mess with those kits but if you're happy with them why not. Typically I flush both of the heater core inlets, flush the engine through the thermostat housing, and flush the radiator through the top, with everything draining out the disconnected lower hose
 
I use a metal "tee-type fitting" The plastic ones can/will crack
 
96XJ_4.0 said:
Would switching to a 185 degree do any good?
Click to expand...

No. Stick with a 195 degree OEM high quality stat. That is the temperature thermostat your 4.0 is designed to use from the factory and will be best for overall efficiency.

The temp spec of the thermostat controls when the thermostat OPENS. It does not limit the high end of coolant/engine temperature. That is controlled by how efficient all other parts of your cooling system are (radiator, water pump, cleanliness of system, proper coolant concentration etc).
 
Thanks for the tips. I do not know of any previous change of the pump or stat. I did not intend to replace them on this flush either... Just want to make sure my coolant system is running clean.

If I do upgrade anything on the coolant system, i'd probably go with electric pump, remove driven pump and mech. fan, replace with Turas or other electric fan, and then, maybe more efficient radiator?? but now I'm dreaming haha. Currently I am running the aux electric fan on a switched relay circuit with a close eye on the temp gauge. Been doing awesome so far, coupled with my custom hood vents! Thanks again guys.
 
Autozone has 3 stats

cheapo-3$

Duralast -7$

other premium brand 10$


Where can I find a good brand name one? NAPA?
 
ehall said:
autozone has a house brand green coolant. so does NAPA, and NAPA sells the Stant thermostats
Click to expand...

NAPA, Pep Boys.

Here is a couple from the Stant website:

ISLAND AUTO PTS WHSE SAN BERNANDINO, CA COLTON TRUCK SUPPLY SAN BERNARDINO, CA
 
OK, gotta wake this thread up. I FINALLY an able to get around to doing this. BIG QUESTION that is killing me...

Which heater hose do I insert the tee??? The hoses that go along the side of the engine are top: 11/16" and bottom: 5/8". I cant figure this out at all! I searched and searched. I realize i want to back-flush the system, so, how do I most efectively achieve this??

Thanks a ton guys!
 
joe_peters said:
Put the "T" from the kit into the heater hose that runs from the heater core to the WP, not the one that runs from the core to the thermostat housing--best to flush the heater core backwards to normal flow.
Click to expand...

4WDlifeform said:
OK, gotta wake this thread up. I FINALLY an able to get around to doing this. BIG QUESTION that is killing me...

Which heater hose do I insert the tee??? The hoses that go along the side of the engine are top: 11/16" and bottom: 5/8".
Click to expand...

They should both be 5/8"
 
ParadiseXJ said:
They should both be 5/8"
Click to expand...

nope. the hose must have been replaced. And i dont not see a thermostat housing? Is it the little guy on the top of the pump housing?

EDIT: so the bottom one then!? And, for better clarification on this, the hose that runs from the heater core, to the lower end of the pump?? im going to post pictures of this... I dont know why this has never really been clarified on here before?? Unless i'm missing something... I appologize if I am. Thanks for everyone's help!
 
96XJ_4.0 said:
And autozone stopped carrying green coolants. Even prestone is all orange?
Click to expand...

FYI, the Preston "All Makes, All Models" is their version of Dexcool.
 
4WDlifeform said:
And i dont not see a thermostat housing? Is it the little guy on the top of the pump housing?
Click to expand...

The knobby thing at the front of the valve cover with the hoses attached to it.

100_0698.jpg


Note: Yours may look different, but you can't miss the placement. follow the hoses.
 
Still... banging my head against the wall on this :banghead: I realize this is stupid simple, but, for some reason its not clicking. I took pics of my system, obviously since something has changed...

DSC_0807.jpg


DSC_0809.jpg


DSC_0808.jpg


OK. I have received a flow diagram, I have looked at that, and I can see that the TOP HOSE flows from the pump to the core. IF I put the tee on that hose, would that would force the flow to reverse due to the heater core being closed by the heater valve!? I dont quite get how I can force reverse flow without pinching off a hose or something.

OR if the above was not right at all, just say, top hose, or bottom hose :looney:

Thanks :dunce:
 
Ok, cancel the thought of "backflushing" with the "T".

To "backflush" the heater core you want to force water through the heater core opposite direction of normal flow--so, remove the heater hose that connects to the water pump, and force water into it. That water will "backflush" the heater core. Some have reversed the hoses between the water pump and thermostat housing and then run the engine, effectively using the system to "backflush" the heater core.

If you splice in the "T" water flow is simply going to be as it is in the normal system. Clear?
 
Clear as mud? I really appreciate the help, I just don't get it. I have never done this before, and I really can't afford to fix anything. So, using the tee, I will get a flush, but just not a back flush? That I understand.

What about the whole system? pump and radiator too? Doing this back-flush by removing the hose and forcing a reverse flow into the heater core, will that get everything? Ill have the bottom radiator hose pulled off to do this... I guess the water will have to come out somewhere??

Thanks again for putting up with my stupidity... haha.
 
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