Overheating in below 0 weather

15 below this morning on the thermometer. Went out to start the Jeep at 6:30 am to take the girls to school.
The Jeep started right up as always and I let it warm up for a few minutes before taking off.
The defroster is usually working a bit when I leave but this AM something was different. I chalked it up to the fact that it was 15 below friggin zero.
Got to the school a few miles away and I noticed an antifreeze smell. Some of you will remember I could never get my gauge to work so that was my only clue that something was wrong.
Shut it down at the school and opened the hood.
The uppper radiator hose was soft and not hot to the touch. Same with the heater hoses.
Fluid levels are fine as I just checked them, plenty of antifreeze but it is a 50/50 mix and I never checked it to see if it was good for 15 below.
I drove it all day yesterday and got home at midnight last night, everything was fine.

I am thinking it's a stuck t-stat. I left it at the school because I didn't want to do any damage but I did try to run it for a few minutes to see if the t-stat freed itself or not.
When I started it it was running very rough so I shut it down and hitched a ride home.
I guess I need to bring it down to the workshop where it is warm and tear into it.
I hope I didn't grenade a head gasket (or worse).
Thoughts or suggestions?

You say the hoses weren't hot, but you don't say if the engine was hot. Most likely it was either frozen coolant or stuck tstat as you suspect. You also say that the coolant level was fine, so I think you would have noticed if it is frozen.

Not to drag the point out, but a temperature gage IS the most important gage on a vehicle. Hope you don't have permanent damage.

winterbeater said:

You say the hoses weren't hot, but you don't say if the engine was hot. Most likely it was either frozen coolant or stuck tstat as you suspect. You also say that the coolant level was fine, so I think you would have noticed if it is frozen.

Not to drag the point out, but a temperature gage IS the most important gage on a vehicle. Hope you don't have permanent damage.

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Engine was very hot, coolant wasn't frozen in the bottle or the radiator.


I know I know, I havent been dilegent to fix the temp gauge but I did try new senders, new wire, etc.
The only thing left is to change the cluster.

Unfortunately, where the coolant really likes to freeze is inside the block.

Where you are, a block heater is a wise investment.

to much water in the coolant mix it 70/30 for winter

Aliendu4 said:

to much water in the coolant mix it 70/30 for winter

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50-50 is generally fine as if you truly do have that concentration, it is good down to -34 below farenheit.

Got her fixed. It was a bad t-stat afterall. Everything else is fine so far.

We'll keep our fingers crossed. You can order a aftermarket temp gage from Summit pretty cheap. Probably $10-15.

I got one of those temp (and oil pressure) gauges from Summit for my '93 but the one I got (Summit branded) had a long probe that would not readily fit in any existing slot. There happened to be a couple of threads along about that time (perhaps couple of years ago) that addressed the issue and I think 5-90 came up with a scheme to insert a right angle plumbing fitting in one of the heater hoses. I decided it would be a lot easier to just swap clusters -- one of the smarter things I've done with the old '93.

As winterbeater suggests, I would get a gauge one way or another.