Its got the pressure cap fitting on it but the part number is right,.. is this ok? how should i set up the caps/ lines.

 

additonal info: its an s4 with the cap on the tstat housing.

 

no matter if you have an S5 koyo and S4 car, or if you have an S5 car and S4 koyo - you can make it fit with a bit of effort.

I actually prefer the S4 koyo. It has the Rad Cap on the top end cap, rather than the way the S5's neck shoots out into the middle of the engine bay.
-a

 

If it's an early '86, you can convert it easily to a radiator overflow. All you need is a later S4 thermostat neck without the overflow nipple and a solid cap for it, then run the overflow from the radiator... a later front overflow bottle would be nice too.

I semi-converted my car, I still use the thermostat overflow but converted to a front overflow bottle.

 

wait,.. so its not wrong,.. its just that i have an early 86?,.. ive never seen an s4 t-stat housing without the nipple at the junkyard,.. ive seent he overflow bottles in the front of the car before though,.. but not an s4 with a cap on the rad,...... maybe im just not being observant.... so a solid cap should work, would a local autoparts store carry one of these? never seen one of them either :-)

 

also whats the big threaded lug for in the lower end tank? is that for a temp sensor/ fan switch?

 

Is it the black plastice screw on the bottom of the rad? If so that's the radiator drain plug. Other than that my s5 koyo had nothing like that.

 

Water thermo switch. It's part of the cold start/high idle system.

 

ahhhh,.. thak you i forgot all about it.

 

Buy an FD one.
It's not as cheap cause it's cast aluminum, but it will never fail like the piece of **** black plastic FC ones.



-Ted

 

a cast aluminum rad cap? so FD's dont have a pressure bypass?... i'll try to get one from the autoparts store when i pick up coolent for the install,.. thank you everyone for your help.

 

That is correct.

If you want to modify it for bypass, drill a hole, use a barbed fitting, and use a sprung bypass cap.
I have one for my FC I custom made myself.


-Ted

 

just last week my heater hose burst and my car overheated a bit. ive been having cooling problems ever since i got my car and i figured id grab a new koyo... turns out everyone is sold out of the S4 ones so i bought an S5 koyo thinking i could make it fit. the radiator is in transit now.. what exactly am i going to need to do to make it work? this is for an S4 NA.. anything i can do to prepare?

 

You really don't have to do anything.
The fan shroud might not fit properly?
You just end up with two fill caps, which can be a good thing.


-Ted

 

haha.. might get a few weird looks.. but i dont pride myself on the attractiveness of my engine bay anyway.. thanks ted.

 

my S4 has a radiator pressure cap in the middle of the radiator as well as a filler cap on the t-stat housing, the radiator has been replaced but before i got the car so i assumed it was right, mine is an '87 T2. i have seen S4 N/As at the wrecking yard with what looks like a surge tank in front of the radiator and a overflow bottle next to that with no cap on the radiator.

 

i currently have a filler cap on my tstat housing, a pressure cap in the middle of my radiator, and the overflow tank in front of the radiator.. anyone want to explain the roles of each of these? filler cap = self explanitory. but the overflow tank has a sticker that says to fill it up from there..? sorry to jack the thread but, what exactly does the pressure cap on the radiator do?