Pettit AST failed.
 

Yup, the cap seating area is definitely NOT making a seal, new cap and everything. The area where the cap sits is extremely flimsy. :icon_tdow

http://i37.photobucket.com/albums/e5...S/100_0620.jpg
fail:icon_no2:

Man, that stinks.

That's why I specified a billet radiator neck on the Fighter's Garage AST - thin metal like that will warp over time if it's just press-formed.

Glad you found the problem, though!

Dale

Thanks for sharing!!

Which seating area? The outer or inner? The outer looks corroded.

outer, its really thin and soft. The Fighters Garage model is available with a billet top?

o.O

So, is it leaking because it bent/collapsed, or because it is corroded and has pits letting the coolant escape? I've rescued quite a few corroded seats with a flat file, polishing out the pits.

Dave

^^it looks a little rusty and corroded, maybe from not using deionized water in the coolant?

i'm having a custom AST made from a local rotary fabricator. I've only used distilled water and coolant in the car, nothing else.