B47 Volvo Penta MD22P-B Oil Pressure Sender

[Nigel]

I have just reorganised my alternator belts, see http://www.bavariayacht.info/forum/index.php/topic,961.0.html
This has caused a problem with the MD22P-B Oil Pressure Sender, see picture:

I know nothing about these pressure senders, in fact I didn't know I had one: I assumed it was just a switch as I only have an oil warning light, not a gauge.

Am I right in thinking they have to be mounted with the switch at the top; to keep any sediment out?
I think I need a male to female spigot to raise the unit 3cm or so. Any suggestions what the thread size may be, and what jointing compound to use?

[geoff]

Nigel the pressure sender can be mounted in any attitude it is only a diaphragm . I would rotate the sender anticlock by 90deg Geoff

[Nigel]

Thanks, I'll do that.

For info, these are the markings on the sender:



Not sure what to make of the "0-10 bar" and the "0.8 ± 0.15 bar"

G Blue
M Black
WK White/Blue

[MarkTheBike]

Could it be that the 0-10bar is the working limits and the .8bar (about 11-12psi) is the trip pressure? Just a guess....

[Salty]

I'm fairly sure the different pressure markings are all to do with the calibration of the meter you use, in that respect it should be stated in the instructions supplied with the meter.

[Nigel]

Could it be that the 0-10bar is the working limits and the .8bar (about 11-12psi) is the trip pressure? Just a guess....

Indeed. Further research seems to imply that this sender unit will work both a light AND a gauge. It would be nice to know for sure, and which terminal does which function.

[MarkTheBike]

Perhaps a multimeter across the terminals would give a clue. Nowt to lose trying.

[Yngmar]

Helps if one speaks German

M = Masse = Ground
G = Geber = Sender (varies resistance with oil pressure between 0 and 10 bar)
WK = Warnkontakt = Alarm Contact (closes if pressure drops below 0.8 ±0.15 bar)

As usual with Volvo engines, the simple instrument panel without the pressure gauge will only have a lamp+alarm wired between M and WK. The fancy instrument panel will also have a gauge between M and G.

Oh, and if you need a new one, these are extremely common car parts. Don't pay the Volvo tax!

[PEA-JAY]

 I confirm the bit about the price. You can buy an automotive VDO 50 mm oil pressure gauge, plastic body and identical to the marine one. Just make sure it's calibrated either 0 - 10BAR or 0 - 150PSI. I fixed one on my boat some years ago.