2.8 oil pressure sending unit Thread size (Page 1/1) jjd2296 OCT 04, 08:55 AM Anyone know off hand what the thread size is on the 2.8/3.4 block for the oil pressure sending unit? I need to find a copper t adaptor so I can run an oil feed line to my supercharger that is being mounted in the ac compressor location. Honest Don OCT 04, 10:56 AM 1/4” pipe pmbrunelle OCT 04, 12:09 PM 1/4 female pipe thread on the factory extension tube for Fieros with A/C. 1/8 female pipe thread on the actual engine block itself. I have the 88 oil pressure sender in a stock-ish location (for A/C cars), and I killed one when rainwater entered via the decklid vent. I replaced the sender and packed the connector with dielectric grease, until it was oozing out when I clipped the connector... it's doing OK for now, but I'm not sure it's a very robust solution. You may want to move the sender elsewhere, where it is more sheltered from water.