MD2030 low oil pressure after oil change

[Ruffles]

Can you make sense of this?

Boat went back in on Friday. Started the engine. Ran it for 10 minutes or so to warm it up. All fine.

Then changed the oil and oil filter. Filled it up with oil and checked the level. Isn't it hard to see the level on the dip stick when the oil is clean?

Anyway, started it up and after a few seconds the oil pressure light comes on. This usually happens after changing the oil; presumably air in the oil system. I normally stop the engine immediately, wait a few seconds, restart and it's fine. This time the alarm comes on again. And again. After some head scratching I check the oil level. It seems I've OVERfilled it. But only by around 1/4l over max. So I pump around 1/2l out and the engine runs fine.

My question is why would overfilling the oil cause low oil pressure? The engine is obviously fine. Revs feely and no smoke at all. Never uses any oil at all.

 

[tinkicker0]

Cos the crank is whipping the oil up into a nice bit of bubble bath instead of the heavy turgid lubricant its meant to be.

 

[Ruffles]

[ QUOTE ]
Cos the crank is whipping the oil up into a nice bit of bubble bath instead of the heavy turgid lubricant its meant to be.

[/ QUOTE ]
Maybe. But it was only a fraction over the 'max' on the dipstick. (Assuming I'm reading it correctly) And the engine was only running at idle.

 

[StugeronSteve]

[ QUOTE ]
Isn't it hard to see the level on the dip stick when the oil is clean?


[/ QUOTE ] About as bad as trying to see the level of dirty oil on one of the new black plastic dipsticks they put in cars.

When you first re-fill the oil has to get around the system and fill the filter bowl etc, so I guess a short period of low pressure is quite normal, but low pressure through an overfill is strange. Must be agitation by the crank, as suggested.

 

[Ruffles]

[ QUOTE ]
Must be agitation by the crank, as suggested.

[/ QUOTE ]
Makes sense. It's certainly fine now.

Thanks all.

 

[boatmike]

Probably had nothing to do with you removing the excess oil. It just took longer than normal to get the air lock out of the gallery where the oil pressure switch is. It pays if you can to pour some oil into the new filter bowl before you fit it if you can, but if fitted sideways on this is messy. Sometimes switching off and leaving it for an hour gets the job done....

 

[steve28]

i usually crank the engine over decompressed until the alarm goes off.


steve

 

[ginestier]

I read this question and answers with interest because I've just done oil & filter change on Leyland Thornycroft 345, and have gone from 40 psi to ZERO! Step 1: I took the filter off & spun the engine, oil comes out under pressure out of filter pipe (messy!). Step 2: I took off the oil pressure sender unit, and no oil comes out of the hole when I spin the engine. Is it possible for the oil pump to have an airlock? Any suggestions would be welcomed!

Thanks

gerard

 

[Ruffles]

[ QUOTE ]
Is it possible for the oil pump to have an airlock? Any suggestions would be welcomed!
gerard

[/ QUOTE ]

Gerard
Contributory factor to my problem was not running the engine for long enough before changing the oil. New oil was therefore probably too thick to distribute itself. (Only occurred to me afterwards that the pump was cool enough to hold in the bare hand when sucking the old oil out..)