Volvo Penta oil sensors

[Naughtigal Grandad]

I'm from New Zealand and I've recently bought a Surtess boat with a Volvo Penta AQAD31A inboard. I note that it seems to have two oil sensors on the same side as the oil filter but on different sides to it. The back oil sensor is not connected (the wire is broken) but the pressure gauge still works ok. If I disconnect the front sensor the needle shots up to max on gauge so I know the pressure gauge is using the front sensor. Can anyone tell me why
1/ there are two sensors?
2/ if there are two sensors then what is the reasoning for two?
3/ will the oil sensor for the Volvo Penta Mercruiser 3.0 4.3 5.0 also fit the Volvo Penta series?

Thanks in advance

 

[madabouttheboat]

Second one is probably an alarm sensor. Does your oil pressure light on the dash come on with ignition and go off when the engine is running?

 

[Naughtigal Grandad]

I don't remember an oil light just the ignition light is on before starting. I'm away for the boat but will check in a few days time. thanks for the reply

 

[snowbird30ds]

I'll second the previous answer, almost certainly the oil low pressure warning switch, chances are they will all be interchangeable with 1/8"NPT thread.

 

[Beneteau381]

I'm from New Zealand and I've recently bought a Surtess boat with a Volvo Penta AQAD31A inboard. I note that it seems to have two oil sensors on the same side as the oil filter but on different sides to it. The back oil sensor is not connected (the wire is broken) but the pressure gauge still works ok. If I disconnect the front sensor the needle shots up to max on gauge so I know the pressure gauge is using the front sensor. Can anyone tell me why
1/ there are two sensors?
2/ if there are two sensors then what is the reasoning for two?
3/ will the oil sensor for the Volvo Penta Mercruiser 3.0 4.3 5.0 also fit the Volvo Penta series?

Thanks in advance

Some engines used oil pressure switches to turn on alternators

 

[VicS]

Second one is probably an alarm sensor. Does your oil pressure light on the dash come on with ignition and go off when the engine is running?

I'll second the previous answer, almost certainly the oil low pressure warning switch, chances are they will all be interchangeable with 1/8"NPT thread.

That is correct

The wiring schematic in the owners manual shows the oil pressure gauge sensor and the low oil pressure warning light/ audible alarm sensor ( #3 and #2 respectively in the snip from the manual )


(#1 and #4 are the sensors for the high temperature warning light and the temperature gauge)

 

[Naughtigal Grandad]

Thanks guys and I too think you are right about the one with the broken wire is a sensor for the oil alarm warming.

VicS - did you find the wiring diagram online as I haven't found the manual yet.

 

[VicS]

Thanks guys and I too think you are right about the one with the broken wire is a sensor for the oil alarm warming.

VicS - did you find the wiring diagram online as I haven't found the manual yet.

The wiring diagram is in the owners manual which can be downloaded from VP's website but it was not straightforward to find

Go to Manuals & Handbooks | Volvo Penta UK & Ireland

Scroll down and enter MD31 in the product Designation box. Select MD31A (INB) and click on search.

Select the Operators Manual that covers AQAD31A, Agree to the terms

Note the file name (7749437.pdf) its been saved as ( you can change that ) and the location of the file.