My jeep over heated on my way to work. Its full of coolant. The fans work the water pump and thermostat are new. I was driving on the interstate in 45 dagree weather when it happened. I'm thinking head gasket or radiator hoses collapsed. Also it has a small coolant leak at tyre water pump but it was full of coolant. Its a 2000 xj 4.0. any thoughts?

 

Also I dove it just now and the temp gauge went from 260 back to 210 pretty quick like the thermostat just opened up

 

It won't start now

 

Cracked cylinder head. Click here for a search on more info.

 

It has a 94 head on it

 

Oh, hmm. Well, how's your fan clutch? E-fan working? In what shape is your radiator? How about the radiator cap? Thermostat installed correctly?

 

Everything is working dine I just took out the thermostat and tested it abd it opened up

 

Well, if everything else checks out, then it is very possibly the head gasket...Any signs of coolant in the oil? Check under the oil fill cap, look for moisture droplets, etc.?

 

Nothing. Looks like black oil. I think I might do a compression test tomorow. But my main concern is getting it started. I had to leave uy at work today

 

So in addition to overheating, it won't start now?

 

Yeah :/I'm replacing crank sensor tomorow

 

Sounds good, are you sure your fans are working properly? Could be temp sending unit, too, but I'm not sure how common that is

 

No its all working. I shut t off on the exit ramp than drive it another 2 miles into the parking lot at work abd it shut off than never ran again

 

Did it act like it was over heating or was just the gauge showing it hot?Reason im asking sometimes factory gauges can read high or even low.

 

No it over heated there was smoke coming from oil filler cap