Slight oil leak

N

newDIYer

Seaman
Joined
Nov 25, 2002
Messages
61
On my 1972 140 HP Mercruiser 3.0L I notice that after running her I have some oil running onto the bottom of the manifold (drips at drain plug) and some running down the engine block below the manifold. It seems to be a very small amount as after 8 hours of operation it is not notible on the dip stick. I can't find where it is coming from. It's not the rocker arm pan cover because that is above the manifold and is dry as a bone. When I had the boat apart this winter I torqued the head bolts to spec as I was having this same issue last year and new gasket on head to manifold connection. Could it be coming from around the head gasket? I can't think of any other place?<br /><br />Thanks for any help.
 
C

crazy charlie

Vice Admiral
Joined
May 22, 2003
Messages
5,581
Re: Slight oil leak

I have the same but not as bad.When I put my hand to the bottom aft manifold I come out with a drop or two.Run a paper towel UNDER the rear edge of the valve cover .Thats the place on mine.Check it out. Charlie
 
N

newDIYer

Seaman
Joined
Nov 25, 2002
Messages
61
Re: Slight oil leak

Thanks for the suggestion. I will check it out again. I have had the rocker pan cover off and when I put it back on I used high temp RTV with the gasket. I would be surprised if that is it. But will check again. <br /><br />Is it possible for oil to leak from around the head gasket?
 
H

horndog

Petty Officer 1st Class
Joined
Aug 6, 2002
Messages
279
Re: Slight oil leak

are you sure it isn't blow by from the breather tube? check that, that will produce small amounts of oil and tends to spray it on and around the engine. <br /><br />The other culprit is usually the valve cover gasket. You shouldn't use sealant there either, but sometimes you should take the repair manual and chuck it, this would be the case. <br /><br />Make sure you clean the gasket surface on the head AND the valve cover COMPLETELY, using degreaser and rubbing alcohol should give you a nice clean surface when using sealant. Sometimes with gasket only a little bit of fresh oil on the gasket helps, it swells the gasket up and tends to seal better especially on valve covers since they tend to warp and are uneven<br />my $.02
 
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