[skullysXJ]

Once the jeep is warmed up if I stay moving it stays at normal heat but when I stop at a stop light for extended periods of time or park and leave the engine on, the temp goes up fairly quickly to around 3/4. The other odd thing is that when the temp is at normal range the heater blows hot air like it should, when the temp goes up the heater blows cool air.

Any suggestions, any info would be appreciated. Thanks!

[rkmark]

Sounds like Thermostat or Water Pump - The cold air is a key indication that it is not moving the hot water around while at idle.

[jwmbishop]

Dang - already using the heater in Utah?

Airflow can effect like this as well as water - make sure the fan is working, their are no bugs plugging the radiator and that the A/C compressor is not running at the same time. get a infrared therm from home depot and make sure of the temp as well (point dot at radiator tanks)- our gauge shows what the computer TELLS it to - a bad sensor could be made worse by the computer - ie temp goes up 10 degrees (no problem) but gauge shows increase comparable to 20.

Low coolant level will also heat as water slows.

[Rudinater]

Originally Posted by jwmbishop

Dang - already using the heater in Utah?

Yes . . . .They had snow out here last week and it's 34 degrees outside here in Logan.

[skullysXJ]

Yeah it's already getting cold! I'm not ready for winter! Summer was far too short!

Fan turns on just fine. I was leaning towards thermostat and water pump as well
thanks, for the info guys

[jwmbishop]

Originally Posted by skullysXJ

Yeah it's already getting cold! I'm not ready for winter! Summer was far too short!

Fan turns on just fine. I was leaning towards thermostat and water pump as well
thanks, for the info guys

At 4 years you are due for Coolant service anyway...

[rkmark]

Use it as an excuse to buy a new Jeep

[skullysXJ]

Originally Posted by rkmark

Use it as an excuse to buy a new Jeep

Well this is already my 4th jeep in 2.5 years and the fact that I brought it home less than a week ago.... yeah I think I'll just keep it haha

[Vin]

when was the last time you had the cooling system serviced? If it's only happening when you are stopped, you may have air in the system.

[rkmark]

Originally Posted by Vin

when was the last time you had the cooling system serviced? If it's only happening when you are stopped, you may have air in the system.

Good point - if this is the case - you could run it with the radiator cap off until hot (yes it will overflow so find something to catch it with) and then continue to add fluid after see the thermostat kick in (usually when the fan kicks in) and the water level drop rapidly. After a few cycles of this - the air should be out of the system.

BUT CAUTION - only take the cap off while cold and not under pressure - if you wait till warmed up the results will not be good.

Also I would advise having someone keeping an eye on the temp gauge - if it goes too far past the middle and the thermostat has not opened, well then you know what the issue is. (Turn it off, let cool down, and replace the thermostat)

Hope this helps