Volvo Penta D4 300 oil leak into bilge and a “rainbow” discharged into sea via raw water

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johngo

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Hi there, I’ve had a look on the forum and cant quite see the same fault that I have so any help to point me in the right direction would be appreciated.
On my starboard engine I’ve noticed an oil (and sea water, I think) discharge into the bilge. Additionally there is a “rainbow” discharge via raw water into the water outside the boat. I hesitate to conclude oil in the rainbow as I’m not 100% certain.(but think it’s probable) The engines are 2012 and D4-300I-E
It may be coincidence that these two events are unrelated and have occurred around the same time but I think that a bit unlikely.

So I think my first port of call in the investigation is to check the charge air cooler, clean it out, reseal and then pressure test it (somehow) would that be correct?
 

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Rainbow could also be diesel in the bilge from a leak , in the water at the exhaust exist ie stern from a faulty injector .
Rainbow at the stern could be a leaky / weepy hydraulic ram from the trim mechanism .With the engines off just operate the trim a few cycles up and down to eliminate or spotlight this .

Excess oil in the CAC generally tends to be blocked crank emissions evaporate systems the ECV You will need to investigate exactly what type of ECV the 2012 D4 has , some one will be along soon .

There also might be a blow off valve on the air side of the CAC ( again you need to investigate the specific D4 nuances) which is releasing the excess oil from either higher than normal crank case pressure or the faulty ECV .

What’s the service history - type of oil used , correct vol put in ?
What’s the usage pattern ? Do you run it as per intended use or just Uber low ( and fuel penny pinching ) rpm ?
 
If its on outdrives, the likely culprit for the oil sheen on the sea water is the steering rams. Barnacles etc grow on the shafts of the hydraulic rams and damage the seals over time, which results in the hydraulic fluid leaking out slightly when you turn the wheel. if you get into the water with a snorkel and mask (engine not running) , and have someone turn the wheel from lock to lock several times you can see a drop of oil exiting the rams and floating to the surface.

As the level of the hydraulic fluid in the steering system gets low the steering starts to feel notchy when you turn the wheel, you can refill the system to keep you going, but you shouldnt run for too long with leaky rams, as the salt water can bugger up the steering system.

The steering rams are a known weakspot on the dph drives, and they underwent several revisions to improve them and make them last longer, the latest versions of the rams are still not perfect and wont last forever, but are much better than the previous versions. The good news is that the rams arent too expensive and are relatively quick to replace.

I've no idea what could be causing the bilge to be oily - but its possible you have two entirely unrelated problems.
 
Hi apologies, I should have stated that it's on shafts. I would also note that the rainbow sheen only appears when the starboard engine is running (i think)
 
johngo said:
Hi apologies, I should have stated that it's on shafts. I would also note that the rainbow sheen only appears when the starboard engine is running (i think)
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ah right , not the steering rams then!

Oil cooler leaking??
 
I believe you are supposed to strip, check and clean all the coolers/heat exchangers every five years. They can corrode and cause leaks apparently. Corrosion protection is not a Volvo strength!
 
I found it easy to get all the oil out of mine! Performs well enough and not hard on fuel. Pain to work on, crap owners manual thing and bits are a fortune.
 
simonfraser said:
what is the Volvo Penta strength ?
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The ubiquitous dealer network .Feeding on the problems posted almost every day on here ( the ones that actually post ) .
Great business modal , something like 50;% T/ O from sales and the other circa 50% from after sales of parts .

Guy opposite with D12 s on a Galeon 53 has been immobile for the past month , an engineer took away a corroded after charge cooler .It’s 10/yrs old .

Had my MAN s CAC inspection two years ago , clean bill ( no pun intended btw ) of health , nothing to do .2003 vintage .

But it isn the £ or €repair bill(s); it’s the hassle in the 4/5 month season imho .

Fortunately neighbour’s dare I say it with MAN powered boats have been taking them out for a cool down swim . :) (y);) .

Got an invite to a Italian berth day party …..

I haven’t said anything btw , in the interest of Italian //British relations
 
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Possibly oil cooler but you would be loosing sump oil level at a fast rate , the housings do rot away on the valves at the rear of the housing so check that area .
 
volvopaul said:
Possibly oil cooler but you would be loosing sump oil level at a fast rate , the housings do rot away on the valves at the rear of the housing so check that area .
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Thanks Volvo paul, i ran the boat for 30 mins at 3400 rpm. When i inspected the leaking side there was only a small amount of oil and water in there.
Can you or anyone alse confirm if the charge air cooler or oil cooler could be the culprit? Where is the actual oil cooler on the d4 300?
Thanks
John
 
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