Oil Leak-gctid825627

[pgiconch]

So I'm going to post the problem without the pictures because I can't get them to upload.

Engine starts and runs well (no missing), sounds good, etc. But after a while it begins leaking - apparently oil out of the top of the oil dipstick at the collar. Is there supposed to be an o-ring that may be missing, or some other possibility? Wipe it all down clean, and let it idle, no oil. Give it some rpms and it starts blowing out the dipstick again. Anyone else had this happen to them?

TIA -

[Centerline2]

it sounds as if the crankcase vent tubes on top of the valve covers have been plugged up somehow..

if the crankcase can breath as it needs to, oil wont be forced up the dipstick tube. no o-ring is used or necessary on at the top of the dipstick tube..

EDIT... excessive blow-by due to excessively worn engine or severe piston/ring damage can cause this also because all the pressure that is being leaked into the crankcase cant be pushed out the normal breather tubes fast enough... hopefully this isnt your problem!

[builderdude]

What Centerline said

[pgiconch]

So the piston/ring damage would be checked by compression testing? Would it show on a plug if I pulled them for inspection? Also, is there a PCV valve in one of the hoses leading out of the valve covers?

[Centerline2]

"pgiconch" post=825652 wrote:
So the piston/ring damage would be checked by compression testing? Would it show on a plug if I pulled them for inspection? Also, is there a PCV valve in one of the hoses leading out of the valve covers?

a compression test will quickly show the type of damage that would be causing that much blow-by...

looking at the plugs may give some indication if you know how to read them, but this is taking into account that you know exactly what the spark plugs in YOUR engine normally look like when it was running correctly and not pushing oil out the dipstick tube. the compression test is more definitive.

and im not aware of any marine engines that use PCV "valves" in the crankcase vent tube coming out of the valve covers.... they should exit the valve covers unobstructed, and terminate at the air intake assembly, so that any fumes can be sucked into the intake and pushed out thru the exhaust...

an engine that is severely over full with oil will push oil up the dipstick tube also, but this should be obvious to you if that were the problem.

[pgiconch]

Centerline -- Your last observation re high oil level may be the answer. Been busy with post hurricane issues in the home and neighborhood. Put boat in water today and checked the dipstick. Seemed to be way beyond the full mark. Couldn't believe it would be that high. Commandeered the Admiral and we pumped out almost 2 gallons of oil!! Concern now is why. Did the folks mess up at the boat yard last time it was in?? Or could be water from a bad head gasket. I left it sit in a clear jug (jugs actually) for a few hours and could not discern any water. It was pretty black, thin and ugly looking (but clear on the dipstick and rag). No gritty feeling. I put some new Quicksilver 25-40 between the add and full marks, and will keep an eye on it daily to ensure it doesn't go beyond that, which would indicate water getting in. Will do some easy low rpm trips around the canals for a couple of days. Hopefully it was just a case of someone messing up at the boat yard. If all seems well after a few trips, we'll drain it all and put all new fresh oil and filter in ourselves. Or myself -- the Admiral wasn't keen on the smell of the old oil.

Oh --- and the oil guage stopped bouncing around like it had started doing. Apparently that is an indication of an overfill issue according to the Mercruiser manual #24. Steady at 25psi at idle and 38-42 at higher rpms.

Keeping my fingers crossed. Will allow me to concentrate on the hurricane related problems (window/hatch leaks & some gelcoat marks from flying debris).

[builderdude]

Hard to fathom anyone overfilling oil capacity by 2 gallons keep a close eye on it, sounds like water ingress to me. Hope I'm wrong.

[Centerline2]

by removing 2 gallons and still leaving the proper amount in the engine would definitely have caused slobbering out the blow-by vents.

any water would set in the bottom of the oil pan and draining out the drain plug will tell quickly if the oil has water in it.... my boat has an adapter that attaches to the drain plug hole in the pan, and when I suck the oil out it removes it from the lowest point of the pan. this is also the dipstick tube. I dont know if this is OEM but its a good way to get all the oil out with an evacuator.

my boat was over full when I got it, but no blow-by...

after changing it myself, I found I had also over filled it by 2" on the dipstick.

I filled the filter before installing it, and when filling the crankcase it took more oil than I thought it should but it didnt come up to the mark as it should have, so I added more until it was full, letting it settle and checking it as normal. (I thought it might be an oversized oil pan)

after running it and shutting it down, letting it set 5 minutes before checking, I found it to be 2" over the full mark. so I sucked some out.

all I can deduce from this is that it seems to either take an unusually long time to run down to the crankcase from the valve cover fill hole, OR more likely, it takes a long time for the oil to make it to the full mark thru the unconventional dipstick tube..... so I will be more careful next time

[pgiconch]

The 2 gals was only about 7 quarts once we checked actual container volumes. I removed the oil using a hand pump via the dipstick tube and it was hitting the bottom of the sump, so it should have brought some water if it were there but didn't seem to settle out of the oil in the jugs. I only added two quarts which brought it right between the add and full mark. I suspect that if the folks at the boat yard were checking it on a trailer and it was sloping forward (low at the tongue end) then the dipstick could have shown low. Or he was told to fill it without checking and just tossed 4/5 quarts in thinking it was empty. Hard to say. Haven't had a chance to lower it back in the water or run it a bit to check. Thanks for the response. I'll stay in touch as time permits.