Oil leak mystery

[SeaMoose]

FL120 early 70’s.

Black engine oil just aft of the shaft coupling. Puddles, and some of it flung about by the shaft. Transmission, intercoolers, damper plate, and oil lines replaced about 250 hours - and 30 days - ago. Transmission oil is clean.

Unless oil can fly… can’t figure out where it’s coming from. About 1/4 cup every 8 hours. Puddles about an inch in diameter.

Suspected exhaust leak initially cleaned lift muffler tightened exhaust T-clamps, lift muffler is clean.

No ideas at all. Any suggestions? Just started 2 days ago.

Alan & Darina on Sea Moose
Hollywood, FL and headed north to Lake Erie

 

[sunchaser]

Are you losing oil from engine? What oil lines did you replace. Paper towels beneath and wrapped around suspect lines and fittings help find some drips. Turbo area?

 

[SeaMoose]

Hi Sunchaser thanks for trying to help.

When replacing the intercoolers replaced all the oil lines for good measure. This is a naturally aspirated engine so no turbo. Can see no evidence of leaks anywhere around any of the oil lines, just the puddles and spray I mentioned aft of the output shaft on the transmission.

In eight hours of run time I loose about a 1/4 cup of oil. Normally the engine doesn't burn any.

Engine real seal is certainly a suspect but I would think I would have oil under the bell housing, can't see how the oil leak would walk down a rotating shaft and find it way out the back of the transmission...

Alan & Darina

 

[RT Firefly]

Greetings,
Mr. S. Buy yourself a florescent dye kit. https://www.amazon.com/FJC-4971-Flu...=uv+leak+detection+kit&qid=1684413533&sr=8-29


I've seen them cheaper...somewhere.

 

[LovetoBoat]

On my trip back to NJ from FL I ran into a guy that said he was on the Great Loop Trip but was in the marina for the last month trying to get an oil leak fixed.
I am sure I will get some of this wrong but the gist is this - he was losing a quart of oil a day. Could not find the issue but wanted it fixed so he could continue his trip - had several different mechanics spend days that turned into weeks without success.

He found a mechanic that suggested he take the boat for a sea trial and he would watch the engine. On the sea trial he noticed that every time a left hand turn was made the oil would leak. But sitting at the dock even at high idle the pressure and torque was not enough for the oil to get by the seal. I do not remember where he told me it was leaking from - but a left hand turn was enough to cause a twist and a leak to occur. Once they identified the source they were able to order a new part and he was waiting for that part to come in. Although I was paying attention I do not remember what part he mentioned - I only remember the story. Not sure this will help you but I think it may be worth taking a mechanic out for a sea trial to see if it avails itself where it is leaking from...

 

[High Wire]

Start at the puddle and work backwards with white paper towels. The puddle had to either drip vertically from above or run across the surface from somewhere or a combination of the two. Once everything is spotless clean, lay out another clean paper towel on the puddle spot. The oil will make a marker trail on the towel pointing out the source.

 

[Comodave]

Greetings,
Mr. S. Buy yourself a florescent dye kit. https://www.amazon.com/FJC-4971-Flu...=uv+leak+detection+kit&qid=1684413533&sr=8-29


I've seen them cheaper...somewhere.

+1. I got a kit on Amazon.

 

[Baker]

Is your engine space spotless??? That is the best way to find a leak.

 

[SeaMoose]

Found the issue, was a mistake by the transmission rebuilder, posted about it on other threads.

Thanks for all the help and yes, my holy space is pristine and gleaming all the time