water temp sensor question

[ADRIANFARINA]

just wondering,
the fan switch is located on the radiator , thats ok.
but why is the temp sensor located on the back of the inlet manifold ? (carb model)
I know it should be on the thermostat housing or on the cylinder head.

[Dr_Snooz]

Well, there's a half-dozen temp sensors on these cars, so it depends on what it's supposed to do. There's the one that tells the gauge what to register, the one that turns the fans on, the one that tells the ECU what to do and the one that starts the fans after the car is off and makes everyone confused. I'm not sure which one is on the intake manifold though. Are you sure you aren't referring to one of the thermovalves?

[HLW]

The temp sensor on the carb intake manifold goes to the temp gauge in the instrument cluster. In the manual it is referred to as the temp gauge sending unit.

[ADRIANFARINA]

I know thats the one , but do I need to know water temp in the manifold , and not the water temp in the cylinder head as most vehicles do?
and another related issue ,
can the Webber swap with that water hole that we close trap some air in the manifold?

[Dr_Snooz]

As far as I know, the only reason to run coolant through the manifold is to control atomization of the mix. Ergo, the only reason to know the temp of the coolant in the manifold is for the same reason. The ECU wouldn't really care about the head temp, but it would care about the temp of the air mix going into the head.

[POS carb]

On the US cars the fan switch is in the radiator, the gauge sender is on the thermostat housing, and the sensor for the engine control module is on the rear of the block under the intake manifold

[ADRIANFARINA]

Wouldn't it be smarter that I install the gauge water temp sensor on the thermostat?

[Dr_Snooz]

That's where it is already?

[HLW]

On the US cars the fan switch is in the radiator, the gauge sender is on the thermostat housing, and the sensor for the engine control module is on the rear of the block under the intake manifold

The temp. sending unit is only in the thermostat housing on the FI cars not the carb'ed cars. This is from personal experience with an 86 dx and an 89 lxi and the shop manual. I don't know why the carb'ed engines run the temp guage from the sensor on the intake manifold but the least critical temp measurement is for the temp guage. It is needed to inform the driver of the general engine temp but none of the engine controls run from the temp guage sendong unit.

[ADRIANFARINA]

That's where it is already?

no, it's on the inlet manifold ..