first off i have a d16z6 in my 89 civic hatch. and my radiator slowly pressurises and all the coolant goes back into the overflow after like an hour of driving, my car doesnt overheat until its low on coolant and also my cars idle drops too 900 rpms and shoots back up to 1500 rpms and it does this all the time, like im reving it, and also when i try to adjust my idle screw it does nothing at all. any ideas on wat could be wrong? anything would help alot!

 

Bleed out all of the air in your cooling system, if this does not work then it sounds like your headgasket took a ****.

 

Sounds like you have air in the coolant system. You shoukd have a bleeder screw on the top water neck where it goes to the cyliner head.

Does your car always ile funny or just when you are low on water? If it idles like that all the time check your iacv on the back of the intake mani there are 2 water lines going to it.

is your cel on?

 

hey mines doing the same thing with my itr swap. i haven't bleed the coolant yet but now i will. also my coolant gauge from the inside acts weird. when i stick the key in, not to start but where all the lights turn on in the cluster. the temp gauges goes all the way up. but when i start it goes all the way down. after the car warms up the temp gauges never moves and it stays down, all the way down it doesn't move at all. anybody know whats wrong with that. i have no check engine light and im getting a high idle at 1500 when car is warm. already cleaned both fitv and iacv