1985 K20 Temp sending unit location?

[7900_Blazer]

I just picked up this beauty for my daughter yesterday (see pic).
All original except for what looks like a GM crate motor.

No working temp gauge (had to buy a hand-held temp gun to check running temp)…

Looking at the motor, it looks like the sending unit is maybe on the top of the thermostat housing??? Maybe?

Thoughts?

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[Blackbeard44]

snap a few pics of the motor, cylinder head or thermostat housing is very common, alot of times the factory guages are not ver accurate but can be consistent and let you know if something is wrong

 

[Rickf]

I thought the sending unit should be in the driver side head or intake coolant crossover.

 

[PrairieDrifter]

That thing on the thermostat is probably a vacuum tree, unless the truck has been messed with the temp sensor probably isn't there, since it would be after the thermostat, not actually measuring the temp in the block.

Like said above, it'll most likely be on the drivers side head close to the manifold, or in the intake. I think 85, it'll still be a single green wire.

 

[7900_Blazer]

That thing on the thermostat is probably a vacuum tree, unless the truck has been messed with the temp sensor probably isn't there, since it would be after the thermostat, not actually measuring the temp in the block.

Like said above, it'll most likely be on the drivers side head close to the manifold, or in the intake. I think 85, it'll still be a single green wire.

Thank you for the direction.

 

[7900_Blazer]

Found the sending unit…

But… Thoughts on these? See pic

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[Deep Creek Square]

That was a ported vacuum switch that has rotted off. The factory location is in the LH cyl head, but if exhaust headers are present it's probably been deleted because it's typically in the way. No reason you cant unthread the vacuum switch and put a sender there. Dorman makes a replacement t-stat housing, just be careful if you go that route as the t-stat bolts have a habit of hanging up in the manifold. Here is a photo of a new housing and sender in my 86 K20.

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[Rickf]

If the t-stat craps out with the sender located on the housing, then the engine can overheat. I have never seen a set of headers that block the sender from being located on the head.

 

[Deep Creek Square]

I suppose these headers could be modified to fit like everything else aftermarket that does not quite fit. But to me a T-stat is a maintenance item it's going to be changed every so often whether its needed or not and certainly at the first sign of sustained overheating.

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If the t-stat craps out with the sender located on the housing, then the engine can overheat. I have never seen a set of headers that block the sender from being located on the head.