Volvo MD1B - Zero oil pressure

[concentrik]

After untangling a prop wrap (while still on the mooring - doh!) I was relieved to find that the gearbox seemed OK but suddenly realised - oil pressure warning lamp on and pressure gauge at zero!! Previously pressure had been good and reliable. Quickly shut down engine and did a quick look around - no leaks, oil level good (but I put a bit more in anyway), no horrid noises - but the oil filter was cold whereas the engine was warm. I'd expect hot oil circulating to heat the filter? So I'm pretty sure there really IS no pressure, not a faulty sensor. What may cause this sudden loss? I have removed the oil pump - all seems OK, the gears are driven OK by the camshaft... I wanted to check the oil strainer but can't find it as shown in the manual for the MD1B - could it be the hex key plug between the oil sensor and the oil dipstick? All help very gratefully received... Andy

 

[pyrojames]

I had problems with an MD2B failing to prime. Th eoil pump seemed to loose oil, and wouldn't self prime, I had to strip it and fill it with oil. In the ned I replaced the pump.

There is also the possibility that you have a poor seat at the dipstick and it is leaking air in to the dip tube. This will also result in zero oil circ.

 

[Ardenfour]

Strainer is the large brass square nut where the dipstick screws into...

 

[Bilgediver]

After untangling a prop wrap (while still on the mooring - doh!) I was relieved to find that the gearbox seemed OK but suddenly realised - oil pressure warning lamp on and pressure gauge at zero!! Previously pressure had been good and reliable. Quickly shut down engine and did a quick look around - no leaks, oil level good (but I put a bit more in anyway), no horrid noises - but the oil filter was cold whereas the engine was warm. I'd expect hot oil circulating to heat the filter? So I'm pretty sure there really IS no pressure, not a faulty sensor. What may cause this sudden loss? I have removed the oil pump - all seems OK, the gears are driven OK by the camshaft... I wanted to check the oil strainer but can't find it as shown in the manual for the MD1B - could it be the hex key plug between the oil sensor and the oil dipstick? All help very gratefully received... Andy

You could have airlocked the pump if the engine was turned backwards by the rope under tension.

If still a problem try putting oil or maybe even grease on the oil pump parts before reassembly and this may help. Wind the engine by hand (decompressed)until oil appears at the pressure gauge connection.

You must have the dipstick in place as this is in the pump suction line!

The pump joint is only thin paper I believe and any thicker can stop the pump priming.

 

[VicS]

Worshop manual might be useful http://www.bluemoment.com/manuals/MD1B-2B-3B_Workshop.pdf

Very important to check the O ring on the dipstick and the joint washer or O ring on the coarse strainer as this assembly is part of the oil pump suction. (Normally)

BUT BUT BUT I have found some indication that there are some engines where these may not be all part of the same assembly and differently located.

It sounds as though yours is not one as shown in the manual. If so then the strainer is the assembly next to the oil pressure sensor. SEE THIS DIAGRAM

 

[Bilgediver]

Worshop manual might be useful http://www.bluemoment.com/manuals/MD1B-2B-3B_Workshop.pdf

Very important to check the O ring on the dipstick and the joint washer or O ring on the coarse strainer as this assembly is part of the oil pump suction. (Normally)

BUT BUT BUT I have found some indication that there are some engines where these may not be all part of the same assembly and differently located.

It sounds as though yours is not one as shown in the manual. If so then the strainer is the assembly next to the oil pressure sensor. SEE THIS DIAGRAM

It looks and sounds like the oil pump may also be different...IE a gear pump and not a lobe pump.. These must be items that changed when it became the MD2???