My 1992 3.0 Mercruiser is losing oil

[sallyboy6]

I run my boat with my friend and it doesnt leak a drop of oil. We ran it hard for 2 hours not a drop missing. Take boat out with wife and kids tubing and down 3 quarts in 1 hour. the boat idles perfectly doesnt smoke and you can eat out of engine compartment. I cant under stasnd how you can lose that kind of oil without seeing evidence of smoke. is there some sort of oil blow by on these motors My first inboard motor. Boat is 1992 bayliner Thanks, Sal

 

[Howard Sterndrive]

Re: My 1992 3.0 Mercruiser is losing oil

do a compression test

something odd there. burning 3 quarts in an hour would make for visible smoke I'd think

 

[littlebookworm]

Re: My 1992 3.0 Mercruiser is losing oil

You're either leaking oil or burning oil. Is there any sign of water in the oil that's left? My guess if your valve seals are worn. That would be good news because a valve job is a relatively simple affair. Good luck. Hy

 

[sallyboy6]

Re: My 1992 3.0 Mercruiser is losing oil

You're either leaking oil or burning oil. Is there any sign of water in the oil that's left? My guess if your valve seals are worn. That would be good news because a valve job is a relatively simple affair. Good luck. Hy

Thanks for tips I think you nailed it pulling head tommorrow piston 4 compression read 215 lbs which we believe has the worst leak of the valves normal read should be 180to 195 hard to believe you can dump that amount of oil in the cylinders without fouling out plugs Thanks Again

 

[Hansolo99]

Re: My 1992 3.0 Mercruiser is losing oil

Be sure to follow up after you pull off the head....

 

[bruceb58]

Re: My 1992 3.0 Mercruiser is losing oil

Thanks for tips I think you nailed it pulling head tommorrow piston 4 compression read 215 lbs which we believe has the worst leak of the valves normal read should be 180to 195 hard to believe you can dump that amount of oil in the cylinders without fouling out plugs Thanks Again

You sure about those readings?

Not sure you have an oil cooler but if you do and its leaking, the pressurized oil could leak into the cooling water.

 

[sallyboy6]

Re: My 1992 3.0 Mercruiser is losing oil

Be sure to follow up after you pull off the head.. I pulled head today and we can tell head gasket worn between piston 2 and three oil in both cylinders high carbon build up in piston 4 and head shows water has gotten into valve area because they are clean as a whistle Cylinder walls perfect no scoring Will bring head to get valve job ,pressure tested, my fingers are crossed this is the problem

 

[sallyboy6]

Re: My 1992 3.0 Mercruiser is losing oil

Be sure to follow up after you pull off the head....

Follow up a couple of guide seals worn not to cause that type of oil loss got a 2007 motor installed for 1500 bucks i guess piston rings were shot. Boat runs great now