I have a EFR 8374, 1.05. The oil drain is taped for a 3/8NPT fitting.

I have tried three 3/8 NPT fittings and they only thread in 1 1/2- 2 threads and stop, as if it is the wrong threading (you can see the anodizing getting scratched off of the leading thread of the fitting).
I understand NPT fittings get bigger the further they are threaded in. But this brings up solid, not the way NPT usually snugs up and gets progressively tight.
Just wondering if anyone else has had the same problem, or if you just used a flange instead?
CW

 

No issues here.

I used 3/8NPT to 5/8" hose barb that is 45 degree bend and pointed it toward the compressor housing.

 

You could get a 3/8" NPT die and cut the threads on the fitting a little deeper