Firestorm500

195* IS stock.

SeaVee

Perfect- thanks. Couldn't find the info in the manual or shop manual I bought

Drossmill06

So in the past 2 years since I started this thread, I have replaced the entire cooling system and the Jeep still runs hot. Even in the winter, the jeep would run around 220. So I thought maybe I put the head gasket on wrong so I went back in and replaced the head gasket. The issue remained so I went back to the drawing board and replaced the entire head with a new one thinking maybe the machine shop screwed something up but the problem is still happening. I have noticed that the aux fan will not turn on until past the red zone. I'm at a loss now and have been just throwing money at this jeep. The only thing I could think that could still be the issue is the cat is plugged up and by me fixing the exhaust leak at the header long ago the exhaust gas now has nowhere to go but be pushed through the plugged up cat. Items I have replaced so far are radiator, thermostat (x2 @ 195), hoses, water pump, installed an aux transmission cooler, new fan clutch (x2), new aux fan, head gasket (x2), rebuilt head from Orielly auto, radiator cap 13 psi, exhaust manifold, flushed the system a lot. Any ideas would be very much appreciated cause I have no idea what is going on.

freegdr

220 pretty norm. Is it sluggish any ? Ia aux trans cooler in front of mechanical fan or aux ? Never replaced cts ?

Drossmill06

It isn't sluggish any and I removed the o2 sensor to create an exhaust leak and it still overheats. In this summer heat (110), it will run at around 260 if I turn on the AC it will go over into the red. Also, it still has the issue of the temp at the thermostat is 200 to 210 when the back of the head at the temp sender is reading 260. The aux cooler runs lengthwise across the middle so it gets a little of both fans. Never replaced the cats since I've owned it at around 209000 miles.

freegdr

Temps measured while motors running ?

Drossmill06

Yes, the temps are when the engine is running for idle for approx 20 minutes it takes to get up that high. Today I put the o2 sensor back in but left it disconnected, and it seems to have helped a bit the temperature difference from the front to back is about 10 - 15 degrees difference. The back of the head at the sensor fitting reads around 230, and the front sensor fitting will read 220. The aux fan doesn't kick on though until about 230 and will turn off at 220. If the o2 is unplugged is the engine switching to a fail safe and creating a rich condition or would it create a lean condition?

elwoodblues

Pretty sure it would be rich.

Is the cat glowing red hot? I think a plugged one would. The efan should come on at 218. Not your overheating issue though, but something to look into once it's more dialed in.

extrashaky

A few thoughts:

Are you sure you're reading the correct coolant temp? If you have an IR thermometer, verify the temp at the thermostat housing, because that's going to be the closest reading you have to your actual coolant temp.

The reason I ask that is that your aux fan should come on at a lower temp than what you reported. So either it's coming on at the right time but your gauge is giving you a false reading, or it's coming on at the wrong time, in which case perhaps you have a bad temperature sensor.

Also, have you done any testing of the block and head, like a leak down test or a combustion leak test? I realize you replaced the head and head gasket, but a cracked block could also allow exhaust gases to spew into the coolant. I would borrow a combustion leak test kit and a leak down tester from Auto Zone or one of the other parts stores and at least try to rule it out.

Drossmill06

elwoodblues the cat is not glowing red hot the reading from the ir temp reader shows 300 before the cat and the cat itself at around 450.

extrashaky I am reading the temp using an IR reader on the thermostat housing and on the brass part of the sensor on the housing. The reading on the back I am pointing the ir sensor at the brass fitting of the temp sender, and it shows close to what the gauge says. The fan will kick on when the thermostat housing is at 230 - 235 and will turn off at around 218. The gauge will be reading at the beginning of the red line when it kicks on, and the fan will drop it back down to around the 3rd line of the gauge.
Before I replaced the head, I did perform a test for exhaust gases, and it did not change colors. I have always seen bubbles coming up through from the radiator fill area. After I had done this replacement of the head, I was waiting for the bubbles to stop but then the coolant started to boil over. If override the aux fan it will keep the temperature on the gauge at around 215, but if I use the ac it will slowly come up.

XJeepCheep

The bubbles sound like a cracked head or even block but who knows. Put a funnel in the radiator and fill it halfway and let it bubble see what happens. Bubbles stop or continue never ending. Maybe just air.

EEVEE

i wonder if your fan clutch is worn out? does it have resistance when spinning it? plus check the electric fan maybe its old and not spinning fast enough. or maybe you have a massive clog somewhere. Ever have rust in your system?

Drossmill06

I'll try bleeding the air out again. The fan clutch, fan blade, shroud, and electric fan are all new and seem to be working. I ordered up a 3 core radiator to see if that helps.