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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Jon87V20 on May 07, 2022, 10:12:28 PM
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The oil pressure sender in my ‘87 Suburban V20 started leaking. I ordered a replacement from Oreilly’s, but it ended up having a different diameter where it threads in. My engine has a fitting between the sender and the block. I think it was probably put there to help the sender clear the O2 sensor.
Anyway, the hole in the block itself is 1/2” too. Oreilly’s says they don’t have that and only have 1/4” or 1/8”.
Do I have some weird size, or is that common? I have a remanufactured 5.7. However, I had transplanted the sender and the fitting from the last engine so that was the same 1/2” as well.
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The oil galley tap down near the oil filter should be 1/4" NPT.
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Okay. Well that's weird. I wonder how both engines ended up having a ˝" tap. I'll go pick up an adapter today I guess. Thanks!
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By any chance, are you confusing 1/4" NPT with 1/2" USS?
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bd, Not sure. I just measured across the diameter of the male side of the sender and it's ˝". So is the female side in the block.
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NPT Thread Size & Pitch: 1/4-18 = Male Thread OD: 13.2 mm / 0.52 Inch = Female Thread ID: 11.2 mm / 0.44 Inch
Need to ask O'Reily if the 1/4 is NPT or Inches!
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NPT Thread [measures] 13.2 mm [across]
This ^^^^^ should sum it up for you since 1/2" = 12.7 mm. The two standards (1/4" NPT vs 1/2" USS) measure w/i 0.020" (0.5 mm) of each other.