Will smaller fitting going to radiator cooler be bad?


Well-Known Member
So here is my problem: i purchased a new aluminum radiator from the forum, and the trans cooler only has a 1/8 npt fitting for the inlet and outlet. Now these are nowhere the same I.D. size of the factory line, (-5 inverted flare).

I am going to be running -6 AN fittings from the trans and into the cooler, and they do make a 1/8 npt to -6AN fitting, but i am wondering if this will cause too much back pressure on the system.

Please help, this is very frustrating.

The factory radiator cooler for the tranny is 1/8"NPT those right angle adapters go into the radiator in the front from the 5/16" flared pipes. :)

It's probably the right radiator for a stock replacement. :cool:

those are the fittings that i am planning on using.

This is kind of making a little more sense to me. Those factory hardlines came in two pieces: the first small ones simple do a 90* degrees bend ad shoot out into the engine compartment. On the other end of that are the flared fittings. Right?
The short bent lines are also 5/16" flared pipe both ends, they mate with the long hard lines with brass 5/16" straight flared pipe couplers on the back side of the radiator.

In the FRONT of a stock radiator are 90 degree or right angle adapters, 1/8" NPT to the 5/16" flared pipe fitting so they stay close to the radiator, there's no way you can fit 5/16" flared pipe into the front of a radiator there's not enough room for the pipe hence the adapters which are low and flat.

That's the way the factory did it, not sure how you're gonna end up. ;)

I think if you use a right angle adapter and your fittings for the tranny are in the front like a stocker it will work out alright and you'll be able to fit the 3/8" or -6an line in there. :cool: