N951CC OiL Change

As I was going through the reams of information about my new airplane, I realized I didn't know when it had it's last oil change. Cessna recommends that you change the oil every 50 hours, but the Cessna pilots association recommends 35 instead and my mechanic recommends 25 hours. I haven't decided on what I'll do yet, but I'll probably go to 25 hours since this is a high time engine and could use some extra TLC now. I know I've put a bunch of hours on it when I flew it back from WI so it was probably up for a change. Looking back into the logbooks, I found that the last change was in 2006 since it hadn't flown many hours since then. It was now 58 hours since the last oil change!

There is a local oil company that carries the aviation oil I use Aeroshell W100 so I bought a case and my mechanic and I changed the oil yesterday. This was the first time I was able to actually see my engine since I was sick during the pre-purchase inspection and the vacuum pump was replaced when I was working. Changing the oil is no different than a car. It's easier since I don't have to jack it up and crawl underneath, but more difficult since I have to remove the cowling and the filter is mounted upside down at a 45 degree angle, which means it spills all over when you remove it. The oil pan has a quick release valve on it so all we had to due was attach a hose and put it into a bucket and push the valve in. This part is a lot easier than pulling out a bolt and getting hot oil pouring everywhere.

My engine is most happy around 10 quarts even though it has a capacity of 12 quarts. I need a minimum of 8 quarts to fly. If I fill the oil to 12 quarts, the first 2 will get blown out the breather port and I'll be right back down to 10 quarts. So I filled it with 11 quarts since almost 1 quart will go into the filter.

While we were changing the oil, my mechanic was casually looking at everything to see what kind of shape it was in. Tug on this lever to see how loose the bearings are, see how tight that is, etc. He found that the airbox, which is the piece that connects the air filter to the carburetor had several sheared rivets. It was still held in place, but was loose. He took the air box off and we pulled out some of the sheared rivets and sure enough you could see they had been sheared for awhile. If they broke recently, the break would look like shiny metal, theses weren't. He also notice that one of the rivet tails was missing and most likely was already ingested into the engine. Good thing he caught this now before more go through the engine. All the pieces are still in good shape so he only has to re-rivet the box back together. Hopefully he'll be able to fix this quickly and we'll be flying soon.

Here are some pics of my engine.