D4 oil sump leak

[mvldyjoan]

2013 R31 sat for several months (travel, hurricanes, etc), during which I noticed minimal but visible oil in the bilge. I've experienced more of a sheen that was cured by a good bilge cleaning. Finally able to get her out for a 2 hour run, engine operation and parameters all normal all the way to WOT. Post-ride inspection revealed nothing new. 2 days later I noticed lots of oil in the bilge and a large puddle near the forward end of the sump. Dipstick indicated at least a pint or 2 had been lost since pre-check on previous run. Using an endoscope camera I was able to rule out the easy stuff, leaving me to the unfortunate conclusion that the oil sump is compromised. There is considerable corrosion showing on the forward face of the sump, but no visible leak; the leak will be underneath in the area too tight for the camera. I was forced to empty the engine oil to stop the bleeding. I am the second owner, purchased in 2018. In my time there has never been any appreciable salt water that far forward in the machinery space, so that much corrosion was a surprise. Anyone experienced this? I do most maintenance myself but do not have the equipment or facility to pull the engine, any way to replace the sump with the engine in place? New one for me, any comments are welcome.

 

[Seakr25]

I highly doubt even in an R31 there is enough clearance to pull and replace a sump in situ. It’s not a desirable answer but you will probably have to pull the engine to properly resolve the leak. That is coming from an R25 owner however, so that opinion for what it’s worth…. God speed, in your repairs.

 

[RMarkSampson]

My R31 was built only one year after yours. First, there are two engines that contribute to your bilge - i.e. also look at your generator. I recently found oil in the bilge and determined it was coming from the generator. Changing out the generator's oil filter and liberal use of Dawn soap solved that issue. Main engine does burn a bit of oil - so to confirm real oil leakage, can you stuff white paper towels everywhere underneath the main engine to see if oil hits a certain area? My only experience with oil leaking was when I pulled the combo "heat exchanger/oil cooler" off the side of the engine. I previously posted some comments on Tugnuts about that episode. There are O-rings associated with the oil cooler being attached to the main engine, and it is definitely a potential source of oil leaking. So, has this assembly ever been removed for cleaning? There are three bolts at the bottom that may not have been adequately retorqued. Same with the assembly that holds the oil filters. Any drips that come off either of these assemblies would end up dripping off the bottom of the engine into the bilge. There is a Volvo Penta Workshop book for the D4/D6 which is really helpful in analyzing potential sources of your leak. If you don't have it, buy it. Good Luck and please let us know if/when you find the problem and fix.

 

[Gypsy]

I have a C28 with the D4 engine. A few years ago I was experiencing an oil leak similar to yours. The leak was difficult to find. Eventually, with the help of a scope the leak was found. At the bottom of the dip stick tube where it enters the engine, there is a shark bite type fitting that the tube fits into. The fitting was leaking. The fitting was inexpensive, but getting to it is tough. Before you pull your engine, get a scope and check the fitting. You might also be able to tell if the fitting is the problem by stuffing white oil pads around it. Run the engine awhile and check the pads.