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Discussion Starter #1
I am helping a friend who is having an issue with his engine over heating. Here is what we have done and know:
- No white smoke out the tail pipe so we know the head gaskets are good.
- No obvious loss of coolant around the intake, thermostat or hoses
- No catalytic convertor so that is not plugged
- No muffler so no restrictions there
- Exhaust has not kicks or major dents in it
- Thermostat has been removed (After the new one did not solve the problem)
- New water pump was installed
- Radiator flows coolant but with all the times it overheated not to sure it is still good.

If any one has any ideas on what else to check let me know as I am out of ideas. Thanks
 

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and, of course , aside from functioning, the fan is powering at both of it's variable temp settings appropriately? Are there and DTCs being thrown?
you do not state any details or model related facts to work with but , fwiw,
3.8L has a 195°F thermostat.
It's fan engages once the temp reaches 215°F, and will turn off when the temp falls back to approx 195°F.

stock, JKs temp can run anywhere up to 215°F-depending on load /speed - prior to the fan coming on.

some common causes for overheating BEFORE it occurs can include:
Low coolant in the radiator ( you said it is flowing so ..)
Is there mud/debris in the radiator or between the A/C condenser fins? It can really get in between these two coolers...
winch or stuff impeding or obstructing air in front of the grill (lights or winch)
bad radiator cap is elusive but a big big cause of this sometimes...been replaced?
You said it wasnt bad radiator hoses
Did anyone verify the relay that is connected tothe upper corner of the radiator is working to regulate the voltage?
that leaves a crappy or inoperative fan; caan you free spin the fan by hand with the engine off ( of course) and it spins freely? If not it is fouled
 

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As above stated, mud between the radiator and the ac condenser is often overlooked and the cause for an intermittent overheating.

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over flow hose good? if its cracked or has a pin hole you may be introducing air into the system
 

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Discussion Starter #9
Sorry, I missed the most important information the vehicle details. It is a 1997 automatic wrangler so the electronics on it are minimal and does on have electronic fan but does have a clutched fan. That all appears to be working properly when running in park.

As for debris between the radiator and a/c cooler there was a little bit but not enough to affect the engine cooling.

When I said it got hot it was still hot to the touch an hour after it was turned off. I was surprised that none of the wiring melted.

This one really has me stumped. Could the transmission or transfer case cause the motor to overheat? It is an automatic and has been sticking some.
 

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97, if the radiator is original it could be clogged. Good news is those radiators or relitivly cheap.

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Clutch fan should NOT spin freely if spun by hand, if it does you need a new clutch
 

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Clutch fan should NOT spin freely if spun by hand, if it does you need a new clutch
I just want to clarify this statement a little. You should be able to turn it by hand, you should feel a load on the fan. If the fan spins without any resistance the clutch is bad and if it doesn't turn without trying to turn the belt also the clutch is bad.

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not that I'm un-empathetic or unwilling to help but once I exerted energy and thought via honest desire to assist another Jeeper with an issue that is superbly documented ( now knowing the concept fully: I.e.- a '97 ) I kinda am turned-off by the fact that the same courtesy wasn't extended by OP and folks come on here seeking savvy, knowledgeable Jeep advice but ask ambiguous and undetailed questions that aren't even about the model this site is here because of.
I have i6 , pre JK JKU Jeeps but cmon. This place is bloody called JKOwners, for cryin' out loud.
JK owners.


OP: this should be moved to appropriate sub section ( "Jeep TJ " I believe )
 
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