So long story short I put a motor in my Z had the cooling system semi bled when I first did it I only had heat when driving not at idle, a week or two goes by I’m driving my car and I loose heat and temp shoots up. Got it towed home Put a new thermostat in it and did the bleeding process again, didn’t work tried both ways with the spill free funnel and FSM way my bottom hose is still cold. When I add coolant to the spill free funnel some will go down but it eventually coolant comes back up the funnel if anybody has any ideas please let me know im assuming there’s air in the bottom hose but I squeezed it I see it burping but hose remains cold??

 

Do fans kick on with your AC on full power?

Sure you have all of the air out 100%?

 

when it ges hot. feel the hoses to the radiator.

is one hot. and one cold?

 

your thermostat isn't opening … either it's dysfunctional or you have air bubbles behind it...

Keep bleeding … look into the lisle coolant funnel / bleeding system

 

IIRC the thred is called, "Burb."