2010 dodge journey overheating

[ruralroute16]

2010 dodge journey with 3.5 had heads, water pump, thermostat, replaced 5 months ago and is now overheating again. The Fan does kick into high as the temp advances. Have found pressure leak in the wall of the overflow reservoir. Used the bag over the overflow tube test to test for head seal leak and there was no significant inflation of the bag after driving a mile or so. Realize gases could be exiting the tank leak instead. Question is: will a pressure leak in the wall of the reservoir cause it to over heat and expel coolant by it's self?

[2late4u]

it shouldn't cause the engine to overheat but it might leak coolant and also not let the coolant return to the rad after it is cooled do to the leak.have you flushed the system and maybe a the rad is partially plugged up, check your hoses to make sure they are not collapsing and closing off coolant flow are you sure they used the right thermostat so many causes, also fan should be kicking on before you reach high temps. how high  are the temps are you talking about?

[Armando G]

Why did you have the heads replaced? Were they warped from a previous over heading issue? Did the water pump give out? 

[rossco]

The short answer to the original post is YES. The cooling system only has a boiling point over 100oc if the system is pressurised. When the resovoir tank splits or the cap seal goes the system fails to pressurise and will boil over quickly ejecting its coolant out the leak/hole point. I'm a motor engineer you can trust me on this one. Also even a partially blocked rad or stuck thermostat will cause this but they are easy to check/detect. 

 

Rossco