I finaly got my FD3S running today, it started right up on the first try. Here is the problem, the pressure relief hose is leaking water pressure. At first I thought it was the cap, but I bought a new cap and the problem continued. During this nine month build I installed a brand new Radiator and front mount intercooler. I relocated the AST. It is the same level as my radiator but lower than the thermostat housing. The car is not over heating but its throwing out almost half gallon of water from the pressure relief hose. Please any and all help is appreciated and no comment is stupid. Thanks!

 

First off is the line from the ast going to the catch tank under the fan relays? Second do you still have the catch tank there? Lastly these cars fluctuate coolant in and out of the catch tank from cold to hot. As it warms up it will push out coolant to the tank. Then as it cools it will use the vacuum to suck the coolant back in.

 

Half a gallon is a lot....like, a lot a lot. Was that an exaggeration or do you really think it's that much?

 

Any updates with this I wish the best of luck.

 

Okay so I did check, and no the car doesn't have an overflow tank. I'm guessing the previous owner removed it.

It is about half to 3/4 of a gallon that comes out.

I have ordered a Universal Overflow tank, and i'll post up what happens as soon as I get it and have it installed.

Thanks for the feedback, I don't know why I didn't think of that earlier. Honestly with everything else I was doing, it never crossed my mind.