my z28 is overheating when im crusing the temp. niddle goes all the way up then when i accelerate it goes tohalf or normal then when i stop is goes to270if anyone had this problem before please let me kno.

 

Im gonna guess you have a air pocket, have you burbed the cooling system?

 

what you mean burbed the cooling system?

 

Doesyour temperature correct itself when the A/C is on?If so, thenyour movingto slowand not enough aircan gettothe radiator.then try a flush and see if that fixes it.

I have to run the A/Calot in traffic because my Z gets dangerously hot FAST!

 

What year is yours? Install the Prestone Flush Kit, and flush it yourself -- cheap at Wal Mart...

Next might want to replace the thermostat if your car is kinda old -- inexpensive, and they do fail...

Next ensure your water pump is not weeping -- if so, it is failing.

 

try bleeding the system, there could be air like mentioned before

also could be your thermostat, but the way you describe it, it sounds like there is air in the system