I had 2 friends with decent automotive knowledge help me out with my car's 2nd oil change. The dealer did the first one free because I went to the "getting to know your car" thing they do.
One of my friends did his car first to show me how to handle the drain plug, filter, etc. He was jealous when I showed him the positions on the subaru
Then we took the oil cap off of my car, and spent the next 5-10 minutes jacking it up, putting it on stands (needed to rotate the tires), getting water, etc. Then I attempted to remove the drain plug.
What happened next is best explained by the term "oil grenade". Very high pressure oil shot out and filled the top of the drain in < 3 seconds. The oil took awhile to drain down the hole in the drain and was pretty frothy. This was not the smooth oil drainage I had just seen on my friends car. Both of my friends seemed to think this was abnormal because we had taken the cap off to relieve pressure.
The rest of the change went without incident. However, they both suggested that perhaps the dealer overfilled the car at the first oil change.
I didn't get any CEL/oil idiot lights. However, engine braking is much smoother now and overall the car feels smoother. Probably just a placebo from doing my first DIY oil change. I have three questions:
1. Are the events indicative of overfilling or something else?
2. What effect, if any, would overfilling the car have?
3. Are there other ways to relieve oil pressure? Hot oil splattering wasn't fun.