Ok so after everytime i drive my hatch and then turn it off and let it sit for a couple of minutes( about 5-10 mins) it throws out water from the radiator cap but still go's into the catch cap. It doesn't over heat or anything when driving the car or when it's just idling . the water temp go's up to 210 and then drops to about 190-200 when the fan turns on. the water pump is new and so is the thermostat,and headgasket, i rebuilt the motor and it has no more then 150 miles(i rarely drive this car). I have also tried three different oem radiators and radiator caps and changed out the stock fan with a slim fan. So what could it be? Has this happen to anyone?

 

Air bubbles? Have you tried to bleed the system?

 

^^thats what i was thinking to

 

how do you bleed the system? is there some knid of valve you have to open to just release the air and not the water?

 

You may just need a new radiator cap.

 

i've tried a new cap and still the same problem.

 

How do you know it's not happening when driving?
If you start it up cold without the cap on, does it bubble? Bad head gasket/poor seal?

To bleed the system, fill it with coolant, squeeze the hoses slowly to move air bubbles out and run it with the cap off and keep adding coolant.

On the D series motors, there's a bleeder valve on the water neck on the head, but not on B series.

 

it had to much water.

 

It may have had air trapped in the heater hose lines. Run the heater whenever you refill the coolant after doin work like a water pump job. Eventually all the air works it's way out of the engine thru the radiator cap overflow line.

 

Thats pretty much how its supposed to work. thats why u have an overflow tank and a spring in the cap. as it cools the spring retracts letting the pressure out and as long as u have the tube down in the tank and its full enough like it should be then as it cools more itll suck some back in as it needs to.

 

the radiator had needed water also the radiator cap was bad so i replaced it with a 1.3 radiator ca. it runs good now or so i hope it keeps on running this good.