[CoyRoberson]

Riding down the interstate, I noticed for the first time that the jeep got warmer than usual. I thought it was because of the coolant leak but I checked the radiator and overflow and they were both full, but the temp was halfway between 210 and redline. Any ideas what could be broken now?

 

[gixxerphil]

I would replace the t-stat, it's cheap.

 

[CoyRoberson]

That's what I was thinking, so I ordered a new housing, gasket and t-stat. May as well replace it all!

 

[CoyRoberson]

Changed my T-stat and housing and the heater hose. Jeep is STILL at about 220ish. Not sure if there is just an air bubble in the system but I'd like some ideas ASAP as this is my daily driver.

 

[4Jeepn]

I would try burping the system to make sure all the air is out.. then see.. if still an issue, also have heard a new cap can sometimes help..

 

[Dextreme]

Could be your water pump is shot.

 

[CoyRoberson]

I will try to burp it tomorrow.

I just had my water pump replaced a year ago after the bearing exploded and shot the fan into the radiator.

 

[CoyRoberson]

I would try burping the system to make sure all the air is out.. then see.. if still an issue, also have heard a new cap can sometimes help..

A new radiator cap? How does that make a difference? I'm curious now.

 

[slomaro]

A new radiator cap? How does that make a difference? I'm curious now.

How Does The Radiator Pressure Cap Work? - Bar's Products International, Ltd.

The pressure cap is similar to the safety valve found on a kitchen pressure cooker. The pressure cap seals the operating cooling system forcing the hot pressurized coolant to carry approximately 50 more degrees of heat than the normal (212) boiling point of water.

 

[CoyRoberson]

How Does The Radiator Pressure Cap Work? - Bar's Products International, Ltd. The pressure cap is similar to the safety valve found on a kitchen pressure cooker. The pressure cap seals the operating cooling system forcing the hot pressurized coolant to carry approximately 50 more degrees of heat than the normal (212) boiling point of water.

Hmm. Never heard that! Learn something new everyday. I just ordered a new sensor, and if that doesn't help it I will get a new radiator cap.

 

[GGA1759]

My Jeep did the same thing with the engine temp. I swapped the T-stat, rad cap, and flushed the system. Still had the problem. Turned out it was the water pump. The rad cap and T-stat are cheap fixes first.
Also if you put the 1/8" hole in the T-stat you don't have to worry about burping it.

 

[CoyRoberson]

My Jeep did the same thing with the engine temp. I swapped the T-stat, rad cap, and flushed the system. Still had the problem. Turned out it was the water pump. The rad cap and T-stat are cheap fixes first. Also if you put the 1/8" hole in the T-stat you don't have to worry about burping it.

Surely my water pump didn't go out in a year!

 

[GGA1759]

It's possible.

 

[CoyRoberson]

I fixed the problem. The coolant temp switch as bad causing it to read high. And then the CEL light was in because I had a misfire on cylinders 1, 2, 3, AND 4. Only thing that makes sense to me as to why that happened was a bit of coolant managed to seep down the threads? I just did a tune up not too long ago with Champion double plats and a new coil pack. But, she's running fine now!

 

[Digger84]

Bad temp reading will make it miss

I tried hooking a temp sensor loose to the harness and if cold engine would start but a warm engine and a cold sensor engine would crank but not start

So a false high temp reading will make it run too lean on warm up causing miss in all cylinders

 

[CoyRoberson]

Bad temp reading will make it miss I tried hooking a temp sensor loose to the harness and if cold engine would start but a warm engine and a cold sensor engine would crank but not start So a false high temp reading will make it run too lean on warm up causing miss in all cylinders

I learn more and more on here everyday.

 

[Morris4x4Center]

Lots of good info in this thread




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