I just drove for a few hours with AC blastin. I really rode it a while today in summer heat. Stopped and had it idling quite a while. Engine began shaking and noticed temp needle was all the way over into red. I just shut it down immediately and hoping she cools. Any comments.......
It's the 6cyl 4.0

 

that's not good... how's the coolant look?

 

Hi and welcome to CF from Tj...Is the electric fan going on? it should when the defrost or AC is on. I would check that first...Tj

 

What's been maintained/replaced?

 

After she cools down check to see if you are down on coolant. Fill her up and see if the truck will run. Hopefully the head gasket did not go or the head did not warp. The 4.0 can take a lot of abuse.

Look for leaks. Check the electric fan to see if it is coming on. Use a meat thermometer to see what temp it comes on at. Go to an AutoZone and borrow their tool to pressure test your radiator and cap. Flush the system. Make sure the coolant is moving through the system (bad water pump, collapsed hoses). Change the thermostat or check it by putting it in a pan of hot water on the stove with a meat thermometer and check to see if moves at the correct temp. Check your exhaust for signs of coolant. Check your plugs to see if they are burning coolant. Check the oil for coolant.


Hopefully it is a hose. Good luck.

JohnB

 

Thank you Donnie, CF, DJ and JOhn B.
I am basically stuck at a busy car wash (with wi fi). I let it sit for an hour and watched temp gauge get down to 200. Just started it and no shaking, rpm is steady and strong, temp is where it should be and both fans were on with AC on. I'll be happy to get it off his lot anyway. I do not work on cars much. I did do an alternator on my wrangler! I may just pul it into Merchants tire up the street. At least I know the manager. Keep ya posted........

 

Everything that he said, plus check the underside of the hood above the overflow reseviour and over the radiator and radiator cap. Coolant is sticky and if you had any coolant leaking out of the radiator cap, from the hose or the overflow bottle you should see evidence on the engine or the hood. If you see it around the radiator cap, consider replacing it, one of the gaskets is leaking, if the over flow hose is leaking you could lose enough coolant over time to cause it to overheat. If however you see coolant around the reseviour that may mean that the coolant system was overpressurized from combustion gasses, this isn't good and could be an indication of a blown head gasket or warped, cracked head. consider testing your coolant for hydrocarbons.

I know it sounds silly but this is how I found my leaking radiator cap, had a nice spray pattern on the underside of the hood.

 

if the coolant is not low or nasty, chances are it's gonna end up being a failed thermostat not opening like it should. be careful.

 

Update: Well, she has been running solid ever since. All gauges are normal. I will continue to look for coolant splash. Coolant looked good and at level.
260K miles!!