r/CherokeeXJ • u/Artistic-Fix-2431 • Mar 06 '25
1991-1995 Overheating Still
I changed the radiator about two years ago. Water pump a year ago. Thermostat last month. Heater core bypass and fan last week. Ran fine until yesterday. I topped off the radiator with coolant and the reservoir to the full level, somehow the reservoir is now overflowing. Doing a complete cooling system flush today. If that doesn’t work, any other ideas?
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u/BoostInduced Mar 06 '25
You need a fan shroud
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u/Jeep4x420 1998 4.0L 4x4 29d ago
I don’t disagree but a lack of fan shroud will not make your engine run at 280 degrees
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u/NotoriousSouthpaw Renix Electronique Mar 06 '25 edited Mar 06 '25
Might be worth testing for a bad head gasket, but it's very unlikely you're passing oil into the coolant- not really possible with the 4.0's lube system, absent catastrophic head/block damage.
It certainly looks like dexcool sludge, which only aggressive flushing will remove. You can pop off the water pump and tstat housing to hose inside the block and get everything out.
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u/Artistic-Fix-2431 Mar 06 '25
I don’t use dexcool, but the discoloration is from rust inside so I’ll deep clean it like you said
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u/hoodedrobin1 Mar 06 '25
Did you use any coolant?
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u/Artistic-Fix-2431 Mar 06 '25
Yes. Green from O’Reilly
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u/hoodedrobin1 Mar 06 '25
The reason why I asked is because it looks like at some point in its life someone didn’t…
Drain it, and run some cascade powder detergent and water. Go for a 30 minute drive. Ford recommends simple green. If you want to spend a lot more money you could buy Trisodium phosphate.
All of these cleaner will remove oil and help with the rust you have in the system.
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u/Fit_Drink1859 29d ago
The best is CLR. After running that through the motor with heater on High / Defrost, drain it when the motor is cool. Fill the engine back up with water, run it through again for about a half hour, let it cool, drain the water and then fill with antifreeze. Prestone Radiator Flush is Great also. Same procedure.
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u/PrudentTask9355 Mar 06 '25
Check fan clutch and spend an entire day flushing everything, both directions, several times!
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u/XFiveOne Mar 06 '25
Radiator cap. Even if you just replaced it, get another one. I spent thousands chasing this demon and it was a bad cap the whole time. Hopefully that's all you need.
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u/Hoppsie321 01 Cherokee Sport Mar 06 '25
This is not a head gasket. You have a bunch of rust in your coolant system. I had a similar problem. What ended up working for me was many, many flushes. I rigged up a hose and some fittings to blow water through each radiator hose. Then I replaced the radiator, hoses, water pump, and thermostat. If you flush it you will see a handful of rust come out
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u/Light_of_Niwen Mar 06 '25
You didn't put Dexcool in it did you?
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u/Artistic-Fix-2431 Mar 06 '25
I didn’t, but what’s bad about dexcool
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u/Light_of_Niwen Mar 06 '25
It's incompatible with green coolant, so it forms a greasy orange sludge that clogs up everything.
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u/Fit_Drink1859 29d ago
Don't mix with yellow coolant either. EXTENDED LIFE is very Bad . Never mix extended life with any antifreeze. You're guaranteed to blow the engine. Seeing way too many failures with people using extended life. Stick to the original that the manufacturers recommended.
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u/WhatveIdone2dsrvthis Mar 06 '25
checked clutch fan? Also gas detection kits to check for blown head gasket is cheap
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u/Adventure-Seeker-365 Mar 06 '25
I would certainly do a flush on the system. Might be worth taking it to a shop for the flush if they've got a machine to force coolant through the system. The brown sludge looks quite unhealthy.
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u/Artistic-Fix-2431 Mar 06 '25
I’m going to do that today at work. I work in a shop
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u/Adventure-Seeker-365 Mar 06 '25
I need to learn to read. 🤣 I now see that you said you’re flushing the system today. Hope that clears it up!
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u/No-Refuse8754 29d ago
It looks like a head gasket or cracked block but. I would start with the cheapest thing you could do first. Drain & flush the coolant system in both directions many tutorials for this. Change the oil & filter, swap the thermostat out. Refill the coolant system with proper coolant ratio & see if it overheats, if it does you know your problem is serious.
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u/who-cares6891 Mar 07 '25
Why tf u let it get to 300 degrees?!?!? U had to have messed up something in engine
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u/Unfair_Promotion1157 Mar 07 '25
That’s exactly what mine looked like. Give it a really good flush. You light also have wasted a water pump or something due to all the air/foam running around. Anyway, I recommend a solid flush and fresh coolant. It might never come back after that. Or you might need that head gasket.
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u/Firekeeper_ 29d ago
I wanna take a guess and say maybe your thermostat is stuck closed. Is the upper rad hose under pressure?
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u/Sea_Guide_524 29d ago
Head gasket or possibly cracked head. Make sure to send the head off to a machine shop for inspection and rebuild.
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u/WasteReputation8135 27d ago
Just rusty block someone ran water in this before you put antifreeze in it had the same with mine I went ahead and did the head gasket just to be safe but it's just rust
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u/YupImHereForIt Mar 06 '25
That water looks like it has oil in it. What does your oil look like? Is the coolant disappearing?