When I drive my Z hard and shut it off, I notice the coolant over flow metal can (APS's replacement bottle) has more coolant than before but it slowly goes back into the radiator... is this common??

The gauge reads fine no signs of overheating... I just hope its not headlift

 

If it were headlift, the coolant would be bubbling out that little vent hole in top.

 

air in the system?

 

I agree it is not headlift, the coolant would be spraying out of the bottle, if you don't have one change the rad cap to a Nismo or equivalent.

 

I get coolant overflow from the overflow tank occasionally.......and I can't be having head lift, I don't think, lol.

 

Coolant res level will rise with heat...perfectly normal. As long as its not bubbling over, you are fine.

 

Will do. However, I did notice one time little drips on the top of the bottle, I guess it came from the little hole.

<------ maximumsportZ posting from friends PC.

 

Mine has been bubbling over the last 10-15k miles. I just keep getting the air purged. could it just be too much or have i been experiencing headlift? F'it new motor should be here soon, but i love my stocker. It has been a champ!

 

Are you letting her idle for a few minutes before shutting her down?