Oil being slung around by alternator belt?

[Lency]

Hello fellow marine engine troubleshooters. Our Volvo D2-75F was recently serviced (professionally), but approx. 100 engine hours later, there was quite a bit of oil all over the place, including a vertical stripe of oil on the walls of the engine bay left and right from the engine). There's also quite a bit of oil under the engine, and on the saildrive seal (see photos attached)

I noticed that the alternator bracket had become loose, causing it (and therefore probably also the belt) to vibrate. I tightened it, cleaned the engine bay's walls, placed some kitchen paper on the areas where the vertical oil stripes were and started the engine. As you can see in the photos, oil drops are being slung around from the belt, but I haven't been able to identify from where the oil comes ONTO the belt. Let alone find out what's causing it.

Curious detail: After having cleaned up approximately 0.5L of oil (and with probably still another 1,5L or so under the engine because it's super hard to reach), I checked the oil level the next day (cold engine) and it's still completely full.

Could it be that the mechanic put too much oil in, causing it to be purged somehow? Or is it more likely there's a different issue?

Thanks in advance to anyone who can offer any insights.

[SailingHarmonie]

Originally Posted by Lency

Could it be that the mechanic put too much oil in, causing it to be purged somehow? Or is it more likely there's a different issue?

Are you suggesting by this that in 100 engine hours you NEVER checked your engine oil level? That you didn’t check it after the mechanic left? Or every operating day?

Before anything other than a wild guess can be made about what is “most likely” some idea about what else that mechanic did, how long ago the service was, how many operating hour on the engine, as a minimum would be helpful

[Lou-In-NJ]

Yes, it is possible the mechanic over-filled your engine, and if I had to guess, the excess oil is leaking, or being forced by internal engine crankcase pressures, past the front main seal and being flung around by the backside of the harmonic balance/front pulley, which would make difficult to see the source of the problem. If your alternator belt has oil on it, clean it and the pulleys, and replace it as soon as it's practical; oil deteriorates rubber, and the belt will slip under load.

You should be in the habit of checking your oil level every day or two when you use your engine. Unlike a passenger car, a marine engine in use is at 75% - 90% load, all the time it is running, and therefore requires more vigilance to keep it reliable.

Lastly, I find the term "professional" usually means someone gets paid to do something, and it doesn't necessarily correlate to competence.

[Lency]

Originally Posted by SailingHarmonie

Are you suggesting by this that in 100 engine hours you NEVER checked your engine oil level? That you didn’t check it after the mechanic left? Or every operating day?

I didn't check it straight after the mechanic left, but I did check it a couple of times over time. I just only noticed oil accumulating in other parts of the engine bay after a while, which is when I started to get more concerned about the oil level. But then again, it was always full. It also didn't appear to be fuller before than it is now, even though more oil has exited the engine in the meantime, which strikes me as kind of weird.

Originally Posted by SailingHarmonie

Before anything other than a wild guess can be made about what is “most likely” some idea about what else that mechanic did, how long ago the service was, how many operating hour on the engine, as a minimum would be helpful

This was the initial service after buying the boat, and was done last summer. The engine hours were around 600H. He basically did a full cleaning and servicing of the engines (fluids, filters, impellers) and cleaned the fuel tanks. He also replaced the shaft as it had some damage due to mal-installation by previous owner's mechanic. That's all I know.

Originally Posted by Lou-In-NJ

...oil deteriorates rubber, and the belt will slip under load.

Yeah, I guess that could also explain my engine's low alternator voltage output warning...

[thinwater]

Originally Posted by Lou-In-NJ

... Lastly, I find the term "professional" usually means someone gets paid to do something, and it doesn't necessarily correlate to competence.

Just as amateur does not mean novice.


I'd wager that >50% of cars never check the oil (about 250 hours, if they are changing synthetic one per year). Not suggesting, just sayin'.



I don't check the oil every day on the boat, but I have always aimed for the "every fill-up" or so target we learned back in the day of cars that used some oil, which worked out to every 10-20 hours of run time. Yes, every long day. I once had an engine run very nearly dry in one day, the result of a sudden leak. Of course, a lot of run time in and out of harbors is no where near full load.


To the point, you ALWAYS check the engine for leaks and level an hour or so after a change. A leak is always possible.

[wrwakefield]

If oil continues to be discharged as though the engine was overfilled, I would double-check the characteristics of the remaining oil in the crankcase (look closely at color of oil on dipstick, or pull a small sample from the crankcase) in case you have a coolant, raw water, and/or fuel leaking into the oil.

Each of these dilutants present differently when mixed with undiluted oil in the crankcase, but the oil won't look 'normal'.

Hoping this isn't the case...

Cheers, Bill

[c.K.]

Originally Posted by Lency

I didn't check it straight after the mechanic left, but I did check it a couple of times over time. I just only noticed oil accumulating in other parts of the engine bay after a while, which is when I started to get more concerned about the oil level. But then again, it was always full. It also didn't appear to be fuller before than it is now, even though more oil has exited the engine in the meantime, which strikes me as kind of weird.



This was the initial service after buying the boat, and was done last summer. The engine hours were around 600H. He basically did a full cleaning and servicing of the engines (fluids, filters, impellers) and cleaned the fuel tanks. He also replaced the shaft as it had some damage due to mal-installation by previous owner's mechanic. That's all I know.




Yeah, I guess that could also explain my engine's low alternator voltage output warning...

Maybe you could have an oil analysis done It could be fuel getting in our oil raising the levels

[deblen]

check oil filter for tightness or pinhole.

[skipperpete]

Hi Lency, considering that the alternator belt is slinging the leaked oil around the machinery space it would be fair to assume that the seal on crankshaft pulley is the source of the leak but there are a couple of other possibilities. There is a lube oil line on the front of the cylinder head near the injector pump, if the banjo bolt was loose or the pipe had a leak, it’s close enough to the alt belt to get oil on it and as someone posted earlier, also check that the lower oil filler cap is tight and has an oring on it. The only other places where oil could leak in that area are the valve cover and rocker box gaskets and perhaps the base plate oring on the water pump">raw water pump.
In the OP you mentioned that the mechanic replaced a shaft, What shaft was that?.