Cooling System

[Hermics]

Hi all. I have a 2004 Liberty w/ 3.7 and auto. I heard a bubbling under the hood. I opened the hood and saw the radiator tank bubbling. With the Jeep running I removed the cap and got a geyser. I changed the thermostat the next day. Yesterday I went to add water with it running and got another geyser. My gauge is reading at the half mark. Any ideas?? Where are your gauges setting. 75 degree day or in the morning she goes to half mark. Thanks

 

[Hermics]

Hi all. I have a 2004 Liberty w/ 3.7 and auto. I heard a bubbling under the hood. I opened the hood and saw the radiator tank bubbling. With the Jeep running I removed the cap and got a geyser. I changed the thermostat the next day. Yesterday I went to add water with it running and got another geyser. My gauge is reading at the half mark. Any ideas?? Where are your gauges setting. 75 degree day or in the morning she goes to half mark. Thanks

Also fan is working but no heat inside the cab when the gauge is at the half point. Thanks again

 

[DadOSix]

Hi all. I have a 2004 Liberty w/ 3.7 and auto. I heard a bubbling under the hood. I opened the hood and saw the radiator tank bubbling. With the Jeep running I removed the cap and got a geyser. I changed the thermostat the next day. Yesterday I went to add water with it running and got another geyser. My gauge is reading at the half mark. Any ideas?? Where are your gauges setting. 75 degree day or in the morning she goes to half mark. Thanks

That dash gauge is not super accurate. Test the coolant temp with either a scan tool, or a point and click infrared thermometer on the outlet port at the radiator.

With the geyser symptom, head gasket until proven otherwise.

Get a shop to test it with the gizmo that hooks to the coolant tank fill. You can also rent /borrow a tester from a local auto parts place. Buy at Harbor Freight.

There is always some ‘flow’ back the small hose on the radiator back to the tank. Your geyser says ‘ excessive pressure ‘ to me.

Hopefully, I am wrong.

 

[sleazy rider]

Hi all. I have a 2004 Liberty w/ 3.7 and auto. I heard a bubbling under the hood. I opened the hood and saw the radiator tank bubbling. With the Jeep running I removed the cap and got a geyser. I changed the thermostat the next day. Yesterday I went to add water with it running and got another geyser. My gauge is reading at the half mark. Any ideas?? Where are your gauges setting. 75 degree day or in the morning she goes to half mark. Thanks

Did you get the thermostat in facing the proper way? If it’s backwards, it’ll do exactly what you’re describing.

 

[LibertyTC]

Use the Mopar thermostat ONLY ! The outside black rubber is the gasket.
Ensure correct orientation.
I've now moved this to the KJ General Discussion Section, as your Jeep is a 2004.

 

[Hermics]

Use the Mopar thermostat ONLY ! The outside black rubber is the gasket.
Ensure correct orientation.
I've now moved this to the KJ General Discussion Section, as your Jeep is a 2004.

Thank you. I’ll get a genuine mopar unit.

 

[Hermics]

Did you get the thermostat in facing the proper way? If it’s backwards, it’ll do exactly what you’re describing.

I’ll double check it. Thank you

 

[Hermics]

That dash gauge is not super accurate. Test the coolant temp with either a scan tool, or a point and click infrared thermometer on the outlet port at the radiator.

With the geyser symptom, head gasket until proven otherwise.

Get a shop to test it with the gizmo that hooks to the coolant tank fill. You can also rent /borrow a tester from a local auto parts place. Buy at Harbor Freight.

There is always some ‘flow’ back the small hose on the radiator back to the tank. Your geyser says ‘ excessive pressure ‘ to me.

Hopefully, I am wrong.

Oh boy I hope it’s not the head gasket. I’ll get it checked out. Thanks

 

[Warpc0il]

I had a similar issue and it was just the cap on the tank not holding pressure, as the rubber had perished. Without pressure the coolant will boil at 100C, while with pressure it will run to 115C without issues. Fitted a new Crown brand cap and all sorted.

 

[Noclutch]

Did you bleed the coolant system ?

 

[Hermics]

Thanks I’ll try a new cap a re-burp the system. Looks like the blend door actuator has gone south so that explains the no heat in the cab. Anyone have any experience with that?? Thanks again!

 

[JeepJeepster]

I had a similar issue and it was just the cap on the tank not holding pressure, as the rubber had perished. Without pressure the coolant will boil at 100C, while with pressure it will run to 115C without issues. Fitted a new Crown brand cap and all sorted.

Water boils at 212F, 50/50 coolant does not.

With a properly functioning cooling system, you do not need a radiator cap under idling/light use. Chrysler actually uses partial pressure caps on other models of Jeeps and they will not build pressure till needed. My ZJ's are like that.

Do you mean to say the reservoir is bubbling? Not the radiator? Its very dangerous to remove the cap while the engine is overheating.

As others have said, you need to try to figure out what the actual temp of the engine is.

 

[uss2defiant]

just get a cooling system pressure tool kit from your LAP. that'll find your leaks pretty quickly.

for the other matter, it Could be your blend door or the resister switch..

 

[Hermics]

Yep turns out it’s the blend door. What pain to get too!! Going to park it through the winter and turn it into a 3 season vehicle. The a/c works great. After the thermostat change it’s staying cool. Thanks!!

 

[DadOSix]

Yep turns out it’s the blend door. What pain to get too!! Going to park it through the winter and turn it into a 3 season vehicle. The a/c works great. After the thermostat change it’s staying cool. Thanks!!

great update!

 

[sleazy rider]

Good and bad news. I hate diagnosing a system with multiple issues. Some gut based guesswork is involved. Glad to hear you’ve figured it out.

 

[Hermics]

Thanks everyone.