My Jeep is Overheating at Idle

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Originally Posted by mk378
And, three pages later, the OP discovers it's only half full of coolant?


Consuming a half gallon of coolant in 300 miles is less than ideal. But that explains the constant overheating. The head is cracked and its pushing it into the oil. These run warm,enough that it usually evaporates off most of the water out of the oil, so they won't milkshake the oil cap
 
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Originally Posted by t1snwrbrdr12
A good cylinder head isn't very expensive is it? The labor is pretty easy as well, nothing you can't DIY at home with basic tools.


That's true. I can probably get a used one pretty cheap and easy. I have done a few before on these engines, it's easier to pull the head off with the intake and exhaust manifold still on. Then swap.
 
If you are running antifreeze, I could be wrong, but I believe there are components that will not boil off that are not good for lubrication.
 
Well I threw it back together with another new thermostat and it's back to running at 195 with no electric fan. Apparently the Stant thermostat I put in earlier this year , to replace the bad thermostat I diagnosed back in May was defective.

Still not sure where the coolant went. But there's a definite massive improvement. Before idling in my yard it would overheat with the electric fan wired on along with the mechanical fan going. Today it was right at 195 without the electric. I like that.

I may get an oil analysis to see if there's a lot of coolant in the oil.
 
Did you run it with a funnel on the radiator fill or with the cap off for awhile? See if any combustion gases are getting pushed into the cooling system? That'd be my worry at this point. You should figure out where that gallon + of coolant went. Of course it's going to run well at this point because it's properly filled with coolant. How do you know the thermostat had failed? Did you run it properly filled with coolant with the old thermostat in before you condemned it?
 
Originally Posted by Miller88
Well I threw it back together with another new thermostat and it's back to running at 195 with no electric fan. Apparently the Stant thermostat I put in earlier this year , to replace the bad thermostat I diagnosed back in May was defective.

Still not sure where the coolant went. But there's a definite massive improvement. Before idling in my yard it would overheat with the electric fan wired on along with the mechanical fan going. Today it was right at 195 without the electric. I like that.

I may get an oil analysis to see if there's a lot of coolant in the oil.

Motorad thermostats are OE if you want an OE one.

I got a Motorad from Auto Zone for my Jeep and later replaced with one from the dealer, which was identical and both stamped Motorad.
 
Originally Posted by t1snwrbrdr12
Did you run it with a funnel on the radiator fill or with the cap off for awhile? See if any combustion gases are getting pushed into the cooling system? That'd be my worry at this point. You should figure out where that gallon + of coolant went. Of course it's going to run well at this point because it's properly filled with coolant. How do you know the thermostat had failed? Did you run it properly filled with coolant with the old thermostat in before you condemned it?


Yeah. The last two times I had to do coolant (thermostat and flush last month) I would run it without the cap for a minute while filling, then turn off and fill while squeezing the upper hose. Then it's usually 2-3 heat cycles and it will usually burp in and out of the overflow bottle and get itself full.




Originally Posted by Nick1994
Originally Posted by Miller88
Well I threw it back together with another new thermostat and it's back to running at 195 with no electric fan. Apparently the Stant thermostat I put in earlier this year , to replace the bad thermostat I diagnosed back in May was defective.

Still not sure where the coolant went. But there's a definite massive improvement. Before idling in my yard it would overheat with the electric fan wired on along with the mechanical fan going. Today it was right at 195 without the electric. I like that.

I may get an oil analysis to see if there's a lot of coolant in the oil.

Motorad thermostats are OE if you want an OE one.

I got a Motorad from Auto Zone for my Jeep and later replaced with one from the dealer, which was identical and both stamped Motorad.


Good to know. I ended up with a motorad thermostat because that's all they had at the advance auto in town. I thought they would just be low end cheap knockoffparts. Granted, the stant didn't treat me too well.
 
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