4.3GL two temperature sensors?

M

Magik

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Jul 9, 2007
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This is more of a general mechnical question. Why are there two temperature sensors (one in the thermostat housing and one in the cylinder head)?

Thanks

Thomas
 
Don S

Don S

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Re: 4.3GL two temperature sensors?

Probably something a previous owner installed. Possibly an overtemp alarm? Hard to say OEM sensors are not in the head.
 
S

SSparkee

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Re: 4.3GL two temperature sensors?

Does your boat have fuel injection? Many cars have the same thing where one sensor is for the engine computer(ECM) an dthe other one is used for the temp gage.
 
H

HT32BSX115

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Re: 4.3GL two temperature sensors?

There's usually 2 sensors depending on year model... (when you have the temp/oil-press/drive oil-level alarm system installed) if the one of them doesn't have a switch (in addition to the temp sender) in it..... the 2 sensors may be in the thermostat housing. (as they are on my 97 7.4L Bravo)​

One is for actual temp sense. The other one is a limit switch for the alarm system. It grounds out the alarm circuit to sound the alarm when the temp goes above a particular upper limit.​

Same for the oil press..... There's another one for low oil press that grounds the same wire and sounds the alarm (drive oil level too)​


Cheers,​

Rick​
 
M

Magik

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Re: 4.3GL two temperature sensors?

Thanks,

That makes sense. I've been looking through the wiring diagrams and I think the one thats in the intake manifold (not cylinder head don't know what i was thinking) is connected to the temp gauge. The one in the therm housing is the alarm switch.

Thanks for replies guys.


HT32BSX115 said:
There's usually 2 sensors depending on year model... (when you have the temp/oil-press/drive oil-level alarm system installed) if the one of them doesn't have a switch (in addition to the temp sender) in it..... the 2 sensors may be in the thermostat housing. (as they are on my 97 7.4L Bravo)​

One is for actual temp sense. The other one is a limit switch for the alarm system. It grounds out the alarm circuit to sound the alarm when the temp goes above a particular upper limit.​

Same for the oil press..... There's another one for low oil press that grounds the same wire and sounds the alarm (drive oil level too)​


Cheers,​

Rick​
Click to expand...
 
Don S

Don S

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Re: 4.3GL two temperature sensors?

So, what year is this Volvo GL? Better yet, what is the full model number, including the letters after the 4.3GL
 
Don S

Don S

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Re: 4.3GL two temperature sensors?

The alarm switch has a tan wire with a black stripe.
The guage sender has just a plain tan wire.
 
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