What is this Sending Unit for?

[Robroy]

I have had some oil leakage dripping down on the passenger side manifold and was convinced it was from a leaking valve cover gasket. After having that replaced it still spills oil at the very end of the manifold near the firewall.

The sending unit on the picture turned out to be a little loose so I tightened it.
Have to confess I don’t know what this is for so I was hopping anyone could enlighten me on the subject?

[drail1eye]

I think it is your oil sending unit

[73 Centurion]

I think that is a tempurature sensor that keeps the fan from running on the heater until the engine is warmed up.

It's a strange creation but useful if you know it's there. On a cold morning fire up the car set the heater on high and the fan doesn't blow. When the engine warms up the fan comes on.

I think this function in over ridden with Defrost.

John

[Robroy]

I think it is your oil sending unit
That would explain my oil leakage since it was a bit loose.

What I don’t get is that there is an oil sending unit near the oil filter also, (see below) I know that since I put a brass-T there for an additional oil sending unit (gauge).
Is there two oil pressure sending units on a 455? :confused4:

[Robroy]

I think that is a tempurature sensor that keeps the fan from running on the heater until the engine is warmed up.

It's a strange creation but useful if you know it's there. On a cold morning fire up the car set the heater on high and the fan doesn't blow. When the engine warms up the fan comes on.

I think this function in over ridden with Defrost.

John
I missed your post John being busy with writing my reply to drail1eye, thanks for the clarification!

That is an interesting function, but it makes sense since many drivers on a cold day put the blower and the heat in full mode thinking it will get warm faster that way. The woman in this household always does and I’m sure she not alone :D

Any idea what could be the cause of the oil dripping on the exhaust?

[centurion 455 ragtop]

I have had some oil leakage dripping down on the passenger side manifold and was convinced it was from a leaking valve cover gasket. After having that replaced it still spills oil at the very end of the manifold near the firewall.

The sending unit on the picture turned out to be a little loose so I tightened it.
Have to confess I don’t know what this is for so I was hopping anyone could enlighten me on the subject?

I am pretty sure it is a temp sending unit for the heads it will trigger a bright red idiot light that says, "STOP ENGINE". It will come on after the amber idiot light comes on for an over heated engine.

[Gum,beest]

I am pretty sure it is a temp sending unit for the heads it will trigger a bright red idiot light that says, "STOP ENGINE". It will come on after the amber idiot light comes on for an over heated engine.

Are you sure Rick?
This sending unit you speak of is normally located on the driver side and has a green single lead on my car

The sending unit that Per speaks of is not present on my car
So i can not check the explanation John has given but its seems plausible to me
On my car the fan works always but maybe that has to do with the fact that i have climate control

[Robroy]

I am pretty sure it is a temp sending unit for the heads it will trigger a bright red idiot light that says, "STOP ENGINE". It will come on after the amber idiot light comes on for an over heated engine.
I had the same thought first Rick, but then I remembered that sending unit being on the drivers side at the back of the engine with one wire connected to it, just as Erik says.

The fact that this unit has two wires connected to it fits with John’s explanation that it’s a sending unit with a switch function.
In the a Buick Service manual I found a Thermo Heat Switch in one of the electrical schematics which has two brown wires connected to it, think that’s it!

[centurion 455 ragtop]

I had the same thought first Rick, but then I remembered that sending unit being on the drivers side at the back of the engine with one wire connected to it, just as Erik says.

The fact that this unit has two wires connected to it fits with John’s explanation that it’s a sending unit with a switch function.
In the a Buick Service manual I found a Thermo Heat Switch in one of the electrical schematics which has two brown wires connected to it, think that’s it!

I wasn't too sure, I would say that you guys are correct.

[Gum,beest]

Per
Did you find out fore sure where the switch is for
i am very curious
I have two therm switches on my car
one is located on the driver side at the back of the cylinderhead with a single green wire attached to it (stop light?)
And one on top of the intake manifold with a green and a dark (brown or black) attached to it (temp light?)
I dont know witch one is witch

Rick says
I am pretty sure it is a temp sending unit for the heads it will trigger a bright red idiot light that says, "STOP ENGINE". It will come on after the amber idiot light comes on for an over heated engine.

I do not have a amber light on my dash both are red on my car
and i ambarresed to say when i boughd my car one of the thermo switches was not attached the result was a blown radiator hose and a call to the roadside help servise (ANWB) on my trip home after buying the car lesson learned dont trust a seller:Dou:
Sinds then replaced the waterpump thermostat and mounted temperature gauges (water, engine oil, transmission oil and a engine oil pressure gauge)

[Robroy]

Per
Did you find out fore sure where the switch is for
i am very curious ......................

Hi Erik,

What John said in post #3 seems to align with what the Buick Service Manual says.
To test this function it needs to be cold, don’t know exact how cold but I think it was stated in the manual.

The sending unit on your manifold nearby the thermostat is for the “Hot Engine” light, the sending unit at the back of the engine (driver’s side) is for the “Stop engine” light which also is referred to as the “idiot light”