The temp gage in my 85 Fiero GT stopped functioning recently. The dealership replaced the temp switch with GM part number 25036809 (TEMP SW) rather than 25036628 (SENS COOL). The replacement part looks like it is longer than the original (some of the threads are exposed). The dealership said the part would work fine (they didn't think the 25036628 was still available (it is via gmpartsdirect.com), and I did want the car back sooner rather than later.

The gauge seems to function OK. Will it be OK to use this other GM part?

Thanks for the advice.

Well... one sounds like the fan switch the other like the guage sender. If the gauge is working correctly, then it's the right sensor.

These sensors and others use "NPT" plumbers threading. It is normal for some thread to show. You actually want to see a few threads.

NPT, National Pipe Thread, and whatever the metric equivalent is called are tapered. It doesn't work like bolts or spark plugs. The threads themselves, and sometimes a bit of pipe dope, form the seal. No gasket required.