Oil Leaks 12V71n's

[Jasper]

How much is “normal” for Detroits Diesel engines to leak oil? I have 12V71n’s.
This is my first experience with DD’s and I am not used to seeing much oil leakage in an engine.
The Port engine has the leaks. Stbd very little.
Each time I have had experienced DD owners and mechanics look at my engines, they say the amount is normal. In fact when I was on a coastal cruise and pulled into a fishing village, one trawler skipper who visited the boat was stunned at the clean engine room and the small amount of oil leaks. Soon I had half a dozen trawler owners who have DD’s visit the boat to see these clean 12V71n’s.
Both engines were overhauled by a well-respected company in Florida. They were not the original engines, I have the photos of them in the factory. Boat is 1971, engines 1980’s. Overhauled in 2009.
The pre-purchase engine survey was very good and showed that pistons were new DD supplied with good hatching marks etc. They had approximately 95 hours when I purchased and although they blew smoke a bit at initial throttle, they settled down well.
Now, after 18 months and 1100 nautical miles, 275 hours of use, the oil consumption has dropped and as for the exhaust, they are running very clean and sound GREAT.
Oil consumption: dipstick down approx. 1/8th after 9 hrs. run, 2 hour at cruise and say 7hrs. at troll speed of 8/10 kn. Same for both motors.
Similar consumption if I have a 2 hour cruise with 20 minutes full throttle. I should be able to give litre/gallon use, but I have been keeping them topped up after each cruise so am not certain, will take note from here on. I have to top up the oil after most trips.
Full throttle, 2250 r.p.m.: 18 to 20.5 kn and running very clean.
Cruise at 1500 r.p.m.: 12/15 knots
Thanks.

 

[Jasper]

More images.

 

[Jasper]

Last group of images.

 

[RT46]

I dont think that is excessive oil leaking at all.

I think you are actually quite clean.

Some of those leaks are not oil but soot from the air box.
Many of the bolt holes on those engines are open to the air box and you can get soot weaping out of bolt holes and airbox covers.

 

[Canuck Dennis]

Yep, I have a pair of those also and yours looks ok about the same as mine with 6000 hrs. port is also cleaner than stb'd.

 

[Jasper]

Thanks Guys.
Appreciate the responses.

 

[Genesis]

Yeah, that's pretty darn good for DDs.

 

[dottieshusband]

Keep some Purple Power from Autozone or the like on hand, it cleans it right off..

 

[Jasper]

Keep some Purple Power from Autozone or the like on hand, it cleans it right off..

We don't have Purple Power Downunder, I use a citrus degreaser. Thanks anyway

 

[jim rosenthal]

Those are very clean-running DDs. You could get Airseps, or Racor crankvents, but I think I wouldn't bother. I'd just clean them off. DDs are kind of like Triumph motorcycles; the oil leaks reassure you that there is oil in the engine and that they are running. Glad your boat is running well.

 

[Avenger]

I think the question was a ruse so he could post pictures of the engines. It's a subtle form of bragging.

 

[rsmith]

Back in the day when they ran DD's in trucks they were known as "road oilers" I've been told the 12/71's were run in trucks that ran across the Rocky mountains. Most of the leaks on the 12's are air box gaskets and valve covers. You can route the airbox drains into the breather tube that comes out of the gear box but I dont like putting that crap back into the blower. If you keep after them they can stay pretty dry but the oil does keep the rust down.

 

[Jasper]

Those are very clean-running DDs. You could get Airseps, or Racor crankvents, but I think I wouldn't bother. I'd just clean them off. DDs are kind of like Triumph motorcycles; the oil leaks reassure you that there is oil in the engine and that they are running. Glad your boat is running well.

LOL!
In fact my first car was a 1963 Triumph Spitfire. It ran for about 3 weeks after I bought it, then died. There was more oil on the floor than in the engine. I ended up selling it with the engine taken apart and in pieces in the boot (trunk in the US).
It was my first self taught lesson in mechanics! I believe it was a failure except I sold the car for more than I paid for it!

 

[Jasper]

I think the question was a ruse so he could post pictures of the engines. It's a subtle form of bragging.

Now I know all is well!
I admit I regularily degrease and clean the engines.
The photos were taken after about an 8 hour cruise, before the clean down.