Hey all;
I'm making a little coolant overflow tank out of some scrap aluminum at work. The tank is pretty much complete but I need to know what size the filler neck is and where to buy one. I don't have a pitch gauge so I can't even measure it myself. Also while i'm asking does anyone know what pressure the cap is set at? 13ish maybe? I looked through my manual and found nothing...tried local MC dealer and got very little love.


Seann

 

You are better off welding in a new filler neck that incorporates a standard filler cap. The pressure of the stock tank is in the upper 20's. I fabbed a tank out of 1/8in 5052 and pressure tested to 65 pounds. You can see the tank in a picture I posted in the "direct air scoop for the intake" thread on page 8 I believe.

Jegs and summit carry the machined aluminium filler and stant 28 pound cap

 

What if the pressure is not the same as factory? Will that not affect the system?

 

I never tested the factory system. I went off of what Canton had on their website. The mini is a closed sytem. The header tank or expansion tank has enough room to fill before pressure gets that high anyway. Since I have built my tank, only once did I see traces of antifreeze from the cap opening. And that was after the car sat for twenty minutes idling in my driveway. It was only a couple of drops, nothing severe.