ATLGT

iTrader: (1)

I just bought an FD and it has an Koyo radiator on it. So here is the problem. When the car heats up, it is able to push the fluid to the overfill tanks but because of the way the radiator cap sits on the housing, it can't suck it back in so the car over heats. My question is is it the radiator cap or the cap housing that is placed onto of the engine?

NeedFD

nearest engine is radiator cap, closest to/mounted onto the intercooler is the AST

ATLGT

iTrader: (1)

It doesnt have a AST. The cap sets below the tube pick up, so I need to know if it is my cap or the black housing the cap goes onto?

Rocking Rotary

iTrader: (14)

Replace them both with factory mazda caps. No sense replacing he one and not the other.

recon fd

You know I have been having a problem with this too. I have a Koyo w/ a AST, but the problem is even though it may overflow into the OF tank it will never return to the system. My filler neck may be low, but my OF tank will OF itself and spill out the little tube. I have no idea why though. Any thoughts for both of us?

DaveW

If the coolant won't return to the cooling system, but there are no other obvious problems, here are a couple of things to check:
1. tube from radiator cap location to OF tank - if there is even the slightest pinhole, air will be drawn back instead of coolant
2. kink in OF tubing, preventing coolant from being drawn back
3. the OF tank may have crud blocking the nipple to the above tube, preventing coolant from returning
4. the spring-loaded radiator cap may not be sealing around its edge, again allowing air to be drawn in instead of coolant

Dave

ATLGT

iTrader: (1)

Ok, so I looked at my Civics radiator to see how it has the cap. There is a small rim about half the way around where the cap goes onto so that the hole to the OF tank is always exposed. Now with the Koyo, that hole is not always exposed. And I got to thinking, if the hole isn't always exposed and the system starts to suck for coolant, how will it be able to get any? The spring will be pulled down from the suction and no fluid will be able to get in.

Also, when I open the cap after the car has been driven and cooled off, I can hear coolant being sucked back up the tube from the OF tank so there are no blockages. I think that maybe the neck or whatever it is called that the cap goes onto is missing the piece like my civic has. So, can some take a picture inside that piece for me so I can see if mine is not right? Thanks.

ATLGT

iTrader: (1)

Anyone have any ideas?

Irgendenner

i had same problem at my old FC

replacing the cap with the springvalve in it will help