Changed my oil today and only about 4 qts came out when I drained it. Did not see any leaks anywhere and have not seen any signs of burning oil.

 

How much was in the filter?

 

That included the filter

 

Was your engine warm when you drained it ? Oil has a tendency to not drain completely on cold engine. Also depending on the service interval you use and miles on your engine could be burning a little overtime with no visual signs.

 

^^ agreed, older cold engines can and some will "hide" oil. Did an oil change on an old '78 LTD with a cold 351w in it only got about 4 and 1/4 quarts out of it (I was told it was low before the change) replaced filter, refiled with 5 qts oil I had, started, shutdown and let sit. rechecked the oil level it was over filled, re-drained got 7 qts out this time (with out removing the filter). I have no idea where the other 2 qts came from. Back to the parts store for more oil I went

 

May be unrelated, but when changing oil, the first thing I do is drain oil, making sure to take cap off refill port, then replace plug on pan. Then pull filter off. Then I go back and pull drain plug again and drain. You'd be surprised how much drains out the second time. Might not be the cause, but good practice.

 

Proper fill with new oil filter is six quarts for the three engines in our trucks. Most of the time this will read overfull on the dipstick. My truck if I drained it at the low end of dipstick it might only have four come out. Also to completely drain an oil filter you poke a hole in the end the drain for up to 48 hours to empty it. The media holds a lot of oil.

 

Nothing to worry about. Don't overthink it too much.