What size are the fittings for the oil cooler on the drivers side of the radiator. I got the wrong sized fittings and want to figure this out so i can start the darn engine tomorrow.

I know they are really close to AN-8 threads, since i installed the fitting wrong and it worked. So its really close to 3/4-16. But i'm losing ground on what else to do to try and nail this fitting down.

If you got a idea, i'm open to hear it.

 

what does the hole measure? i just put a 34 '' rad in my truck for e-fans and i believe they looked like 1/2'' or 5/8 '' NPT.BTW i dont have the oil cooler, just the female fittings on the tank, good luck

 

Well its something around the 3/4" inch range. Thread count is either 18 per inch, or 1.5 per mm. 1.5 per mm seems to be a tighter fit. I'm beginning to think its a 20mm x 1.5

Yet, my trans cooler fittings a 5/8"-18 fits nicely... go figure...


EDIT: ok im sitting here playing with my dial equipped ruler thingy

And 20mm probably is too large. But 3/4" is too small. I wanna smack someone at GM for this design lol