I recently finished turboing a 1.6L miata, but no matter what I try the oil feed fitting that goes in the block (M10 x 1.5 to -3an) continues to leak. I tried a generic decent fitting copper washer on it with permatex high temp thread sealant at first and that leaked, then I tried thread seal with no washer and that certainly didn't work. Next I tried some brake line copper crush washers from advance auto that seemed properly sized and still put thread sealant on it, still leaks. Does anyone know what can be causing this? I cleaned the surface the crush washer sits on, it is a brand new fitting, and I can see If I look from the front of the car that it is coming from the fitting that goes in the block and not the line connecting to the fitting. It starts to seep out even at idle, so I can't even drive the car and nothing seems to work.

 

Are you using a real crush washer fitting or just throwing a crush washer on a normal fitting (that won't work).

M10 x 1.5 to -03 AN Crush Washer Seal Adapter

Maybe you can get it elsewhere.

 

Ordered what you linked, really appreciated. Did not know a generic crush washer would not work.

 

Is a crush washer fitting always needed for that port on the block, or is there another type that will work?

 

Unlike the oil pressure port on the cold side, the hot side feed is a M10 x 1.5 straight thread. You'd need to put sealer at least on the threads or an o-ring under the fitting to seal well. A crush washer with the fitting made for it is foolproof.

 

Thanks!