I have changed everything on the motor. Head gaskets, water pump, radiator, flush.burped air bubbles, thermostat. It seems to be building up back pressure. When I take off radiator cap and rev it up it will push all the water out instead of sucking it in. It don't get hot sitting at idle .it gets hot as soon as I get a half a block down the road. Please help......... I have a 2005 roadster

 

did you get the heads machined when you did head gaskets?

 

Hard to say what's going on with your ZR from just a description. Are both the upper and lower radiator hoses getting hot after the car is warm?

 

Why do so many noobs post in the 370 section

 

Yes I did

 

what's your answer to DK's post #3 - do the hoses get hot?

Possibly your heads / head gaskets got installed wrong and aren't sealing...combustion pressure is seeping out of the cylinders and into the coolant jacket / coolant system forcing coolant out.

 

Air is still in the coolant system.