jeep overheating in MN heat!

[twack]

Its been about 95 - 100 degrees here in good ole MN with index of about 105 - 110. My jeep has been soild to me but in this heat it has been over heating. always overheats if the ac is on full blast but on some of these hot days on long return trips it wiil over heat if the ac is on at all and just running normal on the highway. it will go down if i run the heat. im going to flush the coolant, and other things to suggest replacing while i do this? would like to never have to worry about over heating. i have about 160k on the jeep, and i have washed out the radiator / condensor so its not full of bugs. thoughts?

 

[k99jk99j]

make sure your radiator cap is holding the correct pressure. if it is not your coolant will boil quicker.

 

[SabaII]

I was gonna say to check your rad/condensor for any signs of plugging. T-stat might not be opening up enough. If it has not been done it might not be a bad idea to just replace it. If you wanna meet up I have a temp gun we can check and see if the rad is cooling properly.

 

[trent.brown]

X2 on the thermostat. Check the simplest and most common things first.

 

[Tarikleesimsek]

It's weird cuz when AC on, my engine temp also cools down lol!

 

[tjkj2002]

It's weird cuz when AC on, my engine temp also cools down lol!

That's because the electric fan is on when the AC is on.

If it's only overheating when the AC is on it's not the t-stat.Best to replace the cap and you may have a bad fan or the relay is overheating.

 

[Tarikleesimsek]

That's because the electric fan is on when the AC is on.

aaaaa

 

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I'm in the. Same situation how do I know if it's the fan or relay ..