Dripping oil from Volvo Penta 23HP aft air intake?

[CaptainBob]

I _think_ I have a slow drip of oil from the aft air intake on my 23HP Volvo Penta. There's often a run of black oil, starting from just beneath it, running down to the bilge, where I'm finding about 100ml total of oil every 3 months ish. Inserting a finger up the intake gets you an oily finger.

Odd thing though is that in the year approx since I filled up with fresh oil, the level in the engine has never changed.

Any ideas? Is this normal? Is it a harbinger of doom?

Thanks!

 

[Malish]

Often there is a pipe directing fumes from inside the engine into the air intake and hence out of the engine bay. A small amount of oil will be vented in this process and, because the air intake is cooler, some of this will condense giving you the oily deposit. All engines vent a little in this way but as engine hours / wear increases then so does the amount of crankcase vapour. For a quick test remove the oil filler on top of the engine (Once the engine has warmed up) and place your hand above the filler point; you will feel a light breeze of vapour but it should not be gale force. Whether the loss of oil shows up on the dipstick is really controlled by the amount of oil in the engine sump.

 

[NorthUp]

It may also be a mix of unburnt fuel and carbon blowing back through the inlet valves.
If the engine starts well cold, you can live with it!

 

[VicS]

Oil tends to drip from the aft air intake "frying pan" because that is the one the crankcase vents to, via a hose on the oil filler cap.


It probably indicates that the pistons, rings and even bores are getting a bit worn.
Hopefully it is not unburnt fuel blowing back past an inlet valve. While it starts easily and runs OK just mop the oil up. An oil absorbing pad in the bilge would be a good idea perhaps.

 

[Bilgediver]

Whether the loss of oil shows up on the dipstick is really controlled by the amount of oil in the engine sump.

)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))

Don't forget that the fuel pump is constanlty leaking to the sump on some Volvo MD engines and this can match the oil lost so infer that there is zero oil use. The truth is thet there is constant fuel dilution hence the need to change oil as directed in the manual.

 

[oldsaltoz]

Check the hose on the oil filler is not blocked or kinked and reducing the vacuum.

 

[CaptainBob]

Thanks for all the replies chaps!