[Accelo]

All the aftermarket stuff is junk as far as accuracy goes.

Do not use any tape on the threads when installing.
After installation, I checked resistance between the manifold and the sender outer housing, and it should be essentially zero.

You can still sometimes purchase an AC part new. You can often find NOS ones on Ebay... Avoid the "made in Mexico" ones as the quality suffered when the production was changed.

One of these cheap sensors caused me a lot of headaches before I knew they were all over the map as far as resistance goes.

In my case, I checked everything and ended up replacing the water pump. Which was not the issue but it caused a big one when the casting broke with less than 50 miles on the newly rebuilt pump.
The fan went into the radiator, took out my radiator, fan clutch and fan. My assumption was the prior owner ran the pump to failure and then the re builder was too cheap to check it for cracks.
Later I traced it down to the (Piece of S) sensor. Last rebuild water pump I ever purchased.

Consumers are now the quality control department.
Probably best check is in boiling water (212 F) with a ohm reading of 78 ohms +/- 2.
Most stock gauges when inputted with 79-82 Ohms will read right around 212. This is a general statement regarding GM temp gauges. May or may not be applicable to our C10's but it's correct for the general time period.

BTW the Amazon ACDelco part says "Professional, premium aftermarket replacement".
It also says this: "Temperature Low-100 Degree F inch. Temperature High- 220 Degree F". Exactly what does that mean? No resistance at a specific temp given.
Some guys have been know to purchase three of the sensors and then use the one "closest" and return the others.
Says a lot when they vary a lot even between the same manufacture.
I never trust Amazon till I read all the fine print.

A friend of mine manufactures coffee pots. He has to trace this stuff down all the time. One time even the quality control dept measuring device was off.



Cheers.