Ok so I've searched a lot a there seems to be mixed answers.

I just put a used 4.0 in my jeep. Went through and put new gaskets and such.. New freeze plugs ect. Water pump new too

On it's first long drive it popped a freeze plug out and ended up overheating. Apparently I used the wrong one, I thought head gasket blew. I had the head rebuilt an magna fluxed. New head gasket and reused OEM headbolts due to not being able to find any new ones locally.

I was getting a hard upper hose and put a new rad cap. Also blew the overflow hose out as I suspected it was clogged.

Gets up to temp and keeps going. Creeps towards the red very slowly. Electric fan never kicks on. At one point it overheated and blew the ign fuse under the hood. I hard wired the fan and it stays right past the middle of the temp gauge.

New tstat and all.. What causes the fan not to cut on. And I feel like it shouldn't get that hot anyways.

 

What year?

 

Without knowing year, Off the top of my head the 4.0 should run at 210 degrees, The e-fan should kick on I beleive it is 219 degrees or when A/c is turned on, If you say it is getting hotter and e-fan not kicken on, There is one of your probs, Sounds like you have a bad temp sensor that turns on e-fan..

Ant...

 

Did you install new thermostat also ? Hows fan clutch ?

 

It's a 1995. New thermostat, fan clutch barley spins over once by hand.

 

Bottom hose is not collapsed either

 

When cold ?

 

Yes.. Well I think I'll check here shortly

 

Which direction was spring installed on thermostat ?

 

Should be tight when at operating temp...

 

Well the mechanical fan spins about 1/4 turn before stopping at temp. The electric fan never cuts on. I just put a new coolant temp sensor in.. No fan still.

 

Try hooking 12V. to the fan and see if it comes on,
If not, the fan is not good...

Ant...

 

How old is the radiator? Just because it's not leaking doesn't mean it not plugged/scaled up internally giving poor heat dissipation.

 

Is that e-fan switched via a relay in the PDC? Is the circuit fused? How good is the ground side of the circuit?

 

Did ya try jumping the fan relay yet ? 30 to 87 if I remember correctly.