Spark Plug Change and I found oil

I changed my spark plugs today with 105,000 miles for the first time. While changing my spark plugs the 2 center spark plugs had some oil on them. The passenger side had more than the driver side.

Has anyone experienced this with their truck? What is the probable cause?

I had not issues with my truck before this. No leaking oil or needed to add oil before.

 

There is a seal at the well in the valve cover. It’s rather normal with that mileage.

 

Is it worth doing yourself or paying a shop to do it?

 

Shouldn't be difficult I just did this on my honda. Makes sure to get new valve cover gasket also.

 

Not hard. Buy OEM replacements. Rent a seal press tool from local auto parts store. Need to remove a few things to get to the cover

 

It will take an afternoon. If you can change spark plugs, you can do this.

Dealer would charge $300-500, small shop $200-300