Is this an oil leak? and where from? with picture

[HALover9000]

Hi guys.

You may see my previous thread where I asked about overfilled oil put in by mechanic in VT L67.
http://forums.justcommodores.com.au/vt-vx-holden-commodore-1997-2002/257099-oil-level-again.html

2 days later I drained more than half a 2 litre ice cream container of oil from sump plug and oil level was now 2mm below full mark when cold.

At this time I notice some oil near back spark plug, on other side from oil cap. This oil is brand new transparent and clean so is from the oil change. I cant imagine how it gets to this position seeing oil cap on other side of motor. I think maybe it leaked straight out due to overfill. I worry at that point its leaking out seam in motor.

2-3 weeks later I check oil level again and it is down to halfway between add-full (or Im just bad at reading dipstick). I will watch if it level continues to drop.

Here is a picture that I highlighted area where I find clean oil on outside of motor. Maybe it is there or dripping from above.
https://postimg.org/image/g6nta9dgt/

My question is: If I am finding oil here does it indicate a particular gasket is leaking. I really want to know if oil in this position is an indication a particular gasket being bad so I don't go in blind when asking mechanics about fixing it. (sorry I know nothing about car engines.)

This car did not lose any oil level in previous 12 months (except what it slowly burns). I hope oil level does not continue to drop but I'm afraid since the day after overfill that clean oil started appearing where indicated in above picture.

 

[Tree cutter]

looks like rocker cover gasket is leaking. its a fairly common problem. You will need a new gasket fitted.

 

[wrx884]

yep as above rocker cover gaskets. check the rocker cover itself once its off, too often enough i see these are done up too tight and the cover itself cracks/warps and leaks even after a new gasket change. from memory i think they only needed to be done up to 12Nm so bugger all really.

when checking the oil i generally dont check it cold usually after its been up to operating temp, u let the car sit for 15-20 mins so the oil is still thin enough but has also drained back to the bottom in that time.

 

[Not_An_Abba_Fan]

If it is fresh clean oil, it is probably spilled oil.

You need to check the oil when hot not cold. When it was filled by the mechanic, he probably didn't wait long enough for the oil to drain back to the sump, but generally, when the engine is at running temperature, and you wait a couple of minutes, the full mark on the dip stick is the correct level so that when it is running there is enough oil in the sump for the pickup as well as enough oil circulating around the engine. When cold, or when let sit for too long when hot, the oil level should be a little over the full mark.

 

[Drewie]

When oil is cold it will read higher on the dipstick, if you read the Holden handbook that comes with the car it says to check it hot, ie when filling with fuel after letting it settle for a few minutes.
So I would imagine that if the handbook is worded that way the dipstick is probably calibrated for that scenario. The mechanic would check it hot when doing the service.