oil slick at back of boat

[gerrycole]

i have oil leaking out into the wake.there is no leak into the bilge. the plugs show no carbon. the oil dipstick shows clean oil, no water. there is no blue smoke. oil pressure has dropped to a max of 40 psi. valve seals are hard but not damaged. i am losing about 2 litres in about 4 hours of operation,mostly at low speed. there is no visible crack on the outside of the block. starting engine is a little hard.needs cranking a little while.starts idling rough then clears up. 1993 5 l cobra.

it is what i hoped it was not. internal cracked block between water and oil passages.


thank you for any and all help. gerry

 

[bruceb58]

Re: oil slick at back of boat

I would start with a compression check. That way you can see what the plugs look like and see if you have a ring issue or possible valve seal issue.

 

[tpenfield]

Re: oil slick at back of boat

Welcome, Gerry Cole:

have you checked the outdrive and trim cylinders for oil/fluid leaks?

 

[Maclin]

Re: oil slick at back of boat

You are losing that much engine oil, right? Dipstick level drops and you have to add oil to the engine?

Your engine may have an oil cooler. Thet will be like a heat exchanger and have raw water going around an inner finned compartment the oil travels thru. If the inner compartment is leaking then oil pressure drops and oil gets out into the spent raw cooling water and on thru the exhaust.

 

[bruceb58]

Re: oil slick at back of boat

Maclin, I was thinking the same thing at first but that drive/engine has a PS cooler, no engine cooler.

 

[tpenfield]

Re: oil slick at back of boat

Missed the part about loosing the oil on the dipstick . . . :facepalm:

Can you run it on land using ear muffs and see what you are getting out if the exhaust? I.e. burnt oil, raw oil, etc.

 

[Maclin]

Re: oil slick at back of boat

Tpenfeld, I was not sure about that setup having an oil cooler or not but that was the only thing I know of that could put out that much oil and affect the pressure also.

 

[tpenfield]

Re: oil slick at back of boat

Tpenfeld, I was not sure about that setup having an oil cooler or not but that was the only thing I know of that could put out that much oil and affect the pressure also.

Yup, hard to say . . . Pressure drop could be due to low levels in the oil pan. You don't always get the clearest definition of things through the forum discussions. A hole in a piston would certainly do it, but what are the odds?

Maybe a compression test just to start the ball rolling and establish a baseline of engine condition.

 

[bruceb58]

Re: oil slick at back of boat

A hole in a piston would certainly do it, but what are the odds?

That's what I had in the back of my mind and that is why it was my first suggestion to do a compression test.