Getting hot

[RandysMJ]

My MJ is trying to run hot. It does it when on the interstate and when i go up a long hill. Guess you can say only when it's pushed hard. It will run about 180 with normal driving. Then it will go up to about 220 when i top a hill. One day it hit right at 240. If i leave the heater on it does fine. It will stay just under 210. The elec. fan is wired to come on with the ignition switch. I've also replaced the fan clutch. Anybody have any ideas?

[Pete M]

How old is the radiator?

[RandysMJ]

probably original.

[Pete M]

Probably the problem then. :D Take the opportunity to grab yourself a radiator from a later model XJ as that gives you a radiator cap to help with filling the system.

[RandysMJ]

You think it's clogging up? Or just going bad?

[89MJComanche]

Probably the problem then. :D Take the opportunity to grab yourself a radiator from a later model XJ as that gives you a radiator cap to help with filling the system.

 

 

Forget the Late Model Used XJ Rad.

 

Call 800 Radiator and get your self part number 1193-3PL.

Tell them that you want the same deal as invoice number 70370711.

The Radiator lists for $281. They will sell them for $139. No freight charges, and sales tax. I got a new GDI style Copper Aluminum 3 Row for less than $150 shipped to my door.

 

Then you just need to pick up an overflow bottle from a later model chrysler vehicle. I think that it is Chrysler Sebring that fits best on the drivers side of an MJ/XJ for this swap but any vacume style overflow bottle will do.

 

You will also need to delete a hose junction in your heater hose system to get rid of that pressurized POS bottle in your current system.

 

If you run a real good radiator heater core flush kit before you swap out the old rad you could even swap over to DEXCOOL Orange Antifreeze. It cools better in the summer and heats better in the winter than the yellow/green stuff.

[Pete M]

Be very careful about mixing green and orange antifreeze. Very VERY bad stuff happens to your engine when they interact with each other. I don't know for sure if that applies to all greens and all oranges these days, but when the orange stuff first came out, people were destroying their engines when they topped off the antifreeze in their new cars with green stuff. If you want to swap over, make sure the flush is very, very, VERY thorough.

 

 

P.S. open-style radiator systems are overrated. :D

[feerocknok]

P.S. open-style radiator systems are overrated. :D

Only from a Jeeper... :shake:

[87manche]

if the closed system is so bad then why is it becoming prevalent again?

I think that what most people blame on the cooling system design is likely because we're all dealing with 15+ year old trucks.

Mine works just fine, it just takes a little more maintenance, and I've still got a rad and hoses from 1987.

[89MJComanche]

The closed system is not really that awful bad.

 

But the plastic bottle is hard to find replacement for when it cracks.

There are way to many hoses in the system going to the bottle.

It is hard to get cool water into the system quickly without a radiator cap

It is just a better system in my opinion.

 

 

As for mixing green and orange...

 

don't DO IT!!

 

You must fully flush out the system with clean water.

[partsmj]

I have always had Jeeps from 90 and older and always used the factory setup. As long as the fan comes on, before your Jeep has a

Chernobyl meltdown,

http://www.chernobyl.com/info.htm

you should be ok.

If the radiator is in doubt,

replace it with the most rows you can find.

Two is good, three is better.

 

http://www.radiator.com/conversation.ph ... go%21.y=14

 

Good luck.

[RandysMJ]

So everybody thinks it's my radiator? What if i ran some flush through it to see if it's clogged some?

[Hot Rod Jeep]

It's been my experience on the closed systems if the fill jug is cracked or not sealed properly in any way it'll run hot. I hit an owl and had to end up changing the radiator due to it's beak puncturing a hole in it and it was too rotten to fix. When I replaced it, I changed over to the open system. 8)

[Pete M]

So everybody thinks it's my radiator? What if i ran some flush through it to see if it's clogged some?

 

 

I don't see how flushing will remove a clog. Won't the water just flow through the unclogged ports? :dunno:

[87manche]

the way the XJ radiator is designed makes it prone to clogging up.

The real long cross flow just makes the bottom of the radiator th perfect place for sediment and scale to drop.

[ORCA]

Just replace the rad. (Expecially if the rad is OEM). And whatever rad hoses you can afford at the time. You may want to replace the thermostat too while your in there (it's easy to do).

 

Your current aux fan is hooked up to the ignition switch, but i've always liked them on my own toggle switch inside the cab (it's super easy to wire up like that anyway) Then you also get the freedom of turning it on and off. :brows:

 

Overheating sucks. :headpop:

 

Oh and did anyone mention standard operating temperture for these I6 engines? It's between 180-220 if i'm not mistaken, so really your truck aint that bad. :chillin:

[87manche]

thermostat is supposed to open at 195.

normal op temp is between 205-215

while wheeling mine usually sits at 220 when wheeling in high eat.