Oil Under Spark Plug Cover
 

98 V70XC AWD Turbo here with 140K miles on it. I have been trying to solve a problem for some time now. I keep getting oil collecting on top of the engine under the spark plug cover. I cleaned all the oil out and changed the oil filler cap gasket but the oil still came back. Next I completely changed the oil vent system (vent tank, hoses, vacuum line, & cleaned the PTC valve) but the oil is still collecting. I now see where the oil is coming into the area but cannot determine how it is getting in there. Here is a picture of the area. The two white arrows are pointing to the port that the oil is comming from. It is not a pressure leak because it takes a while to fill the port up but once it does fill it will then start to run to the back. If left long enough (20k-30k miles) it the oil flow out each end of the cover (into the timing belt area and off the back of the engine to the turbo area, the two yellow arrow areas). Can anyone tell me what this port is? Is there something missing here? It looks like something should be bolted over the port. It has two bolt holes around the port, and the port opening has a machined area that would accept an o-ring to seal it off. Any help would be appreciated.

I believe it is a freeze plug that goes in there, not hard at all.

Not so sure it has ever had anything in there at all. Take a look at this thread on the same issue on another forum.

http://www.matthewsvolvosite.com/for...hp?f=1&t=30678

Well it looks like a tube goes in there, so if you do not have the tube, then there should be a plug that goes in there.