Coolant sealing a Thermal Vacuum Switch

78Delta88 said:

Are part numbers the same? This later one is NPT or at least appears so. Above the threads is not machined as the other appears to be. Maybe all was just optical illusion due to angle of photos?

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Yes, same part number. And yes, optical illusion. It would be totally out of whack for a coolant passage screw-in sensor was not a pipe thread. I'm always open for convincing otherwise, but nobody's been able to do that yet.

Ultra grey

69hurstolds said:

Yes, same part number. And yes, optical illusion. It would be totally out of whack for a coolant passage screw-in sensor was not a pipe thread. I'm always open for convincing otherwise, but nobody's been able to do that yet.

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I've seen, o-rings rarely, usually more with a gasket, NPT, and the Japanese like Banjo Bolts. Most older years... (85 and older) Were/are NPT. Photo of the orifice that the sensor/sender is going in, would answer it. Mainly in production decisions are based around tooling and value added work, as far as the process goes.

Drilling and threading a boss for NPT has less operation in production and allows for better error proofing... (Less defects). Straight cut threads with o-ring or gasket requires tighter specification, more labor cost, and more potential in creation of non-conforming material or defects. Anyway so much for the engineer side of the brain.

GM was/is always cheap.