Well got my pressure switch and tools ready to go. Removed oil pressure switch noticed it had a crush washer on it and my new switch doesn't. Went back to Auto Zone the other two they had are missing it. The computer description say it should have it. Contacted Chevrolet dealer they say it should have it. So now I'm on hold for two hours till the dealers gets one in. I won't be a happy camper if I to put the old one back in.
Crush washer

 

Are you sure it is a crush washer looks like a copper banjo fitting washer to me, maybe oil drain. Unfortunately they sell them by the bag.

My service manual does not show any sort of washer or gasket.

 

Brand new from the Chevy dealer. They call it a crush washer. It is installed and done. If you do this make sure to use electrical cleaner to get the oil out of the plug.

 

CHECK THE PRONGS TO MAKE SURE THEY ARE NOT OUT OF ALIGNMENT - don't ask me how I know.... The plug would not go in.... I coated the threads with GM head bolt sealer because I had it.

 

Good tip!!!

 

so is it no way just tighten this sensor - anyway should I find the new one? Maybe just the washer? Not sure I'll find it so fast tomorrow - I have no car yet, motorcycle is garaged, don't want to take off starter one more time... I know if the oil was leaking from oil pan bolt on the trucks - I was replacing just a new copper washer.

 

 

Does somebody know what is the thread diameter on that sensor? - I had some copper washers in my toolbox.

 

 

Yes. If you're going through the trouble of pulling it out, just put a new one in. Why take any chances on an old sending unit. They don't cost much anyhow.
Better safe than sorry.