Volvo Penta 2003 - Oil Pressure Sender

[islandrunner70]

I have a 1993 Beneteau Oceanis 370 which has a Volvo 2003 model diesel engine. I have owned the boat for 2 years and have gradually been learning more about this particular model of engine so that I can properly care for it.

I was studying the engine workshop manual and identifying the related components on the engine.

What I noticed is that the engine has an Oil Pressure Sender sensor (#4 in pic) which I believe is required for an oil pressure gauge. My boat does not have a oil pressure gauge but only an alarm for the sensor.

Will this still cause an alarm to sound since it is not an "oil pressure alarm sender"?

Thanks

[Doug Brown]

When you turn the key on but don't start the engine, the alarm & light should go on.

If you want to put in a oil pressure gauge, you can either install a sender for just an oil pressure gauge (no alarm), or one that keeps the alarm function as well as works a electronic oil pressure gauge (VDO gauges and sender).

You can also install a "T" fitting and keep your original "alarm sender" and install a mechanical oil pressure gauge. This is what I did. I have a set of mechanical gauges (oil and water temp) mounted down below under a step on the companionway, as well as the factory gauges out in the cockpit.

If you have the salt water cooled engine, they are great and will last forever if you just do basic maintenance on it.

My engine is 31-years old and still developes the factory oil pressure while running (52-54 psi) and at idle (46-48 psi). Engine water temp is between 132-134 F when running.

[model 10]

There are basicly 2 kinds of senders. They often look the same. One is an on/ off switch that turns on a light or an alarm the other is a variable resistor that sends a signal to a gage for pressure or perhaps the lack of. If you have just a light on your boat , it's a switch style sender.

[DougR]

Hello Islandrunner,
Beneteau boats of that era were equipped with the "standard" VP instrument panel, which did not include an oil pressure gauge. The engine was fitted with an oil pressure switch which breaks electrical contact when the pressure is adequate and closes contact if the oil pressure is too low, sounding the alarm. This switch was mounted on the front of the engine, just above the crankshaft pulley and in most cases it has a single blue and white wire running to it. You can test the system as follows: start the engine and remove the wire from the switch (careful of the rotating belt)...then ground the wire to the engine block. The alarm should sound and the idiot light should come on whenever the wire is grounded.

Later engines were equipped with an isolated electrical system, and the switch had two wires connected to it, one black(ground) and the other blue/white. The test procedure is basically the same, except you ground the blue/white wire to the black ground wire.

You can easily test your sender or switch more or less the same way...Disconnect the wire from the switch and put one lead of an ohm meter on the switch terminal and the other lead on ground. When the engine is not running there should be 0 or very low resistance thru the switch, and when the engine is running the switch should be "open " or no continuity.

When the engine was delivered with the "deluxe" panel, which included an oil pressure gauge, there was an oil pressure sender mounted on the engine to drive the gauge. Usually this sender was mounted on a seperate remote bracket and connected to the engine with a hose. This sender would have had a brown/white wire and a black ground wire connected to it.

My guess is that your engine is a late model version (production of the 2003 ended in'93) with the two wire oil pressure switch, and that is why it looks something like #4 in the schematic, but you can test it as described above.

Hope this is helpful.
DougR

[Slowtack]

Thanks DougR, I am adding that to my engine manual

[jamhass]

A minor point on the Volvo 2003 oil pressure sender:

The oil pressure sender that comes with the Delux instrument panel is both a pressure sender and alarm switch. It is 2-wire, one for the pressure and one for the switch, both of which rely on the sender body being grounded via the engine.

As mentioned earlier one can fairly easily add a separate pressure sender via a common plumbing tee but be very careful to identify the threads. While the threads may seem to be 1/8 NPT, it is very possibly they are 1/8 BSP (an older British pipe thread commonly still used in engine applications) Mixing the two can result in broken parts, leaks or both.