As the title implies, when I’m doing my oil changes, I’m only getting 4.5 quarts out, but my engine calls for 6 quarts. This has been consistent for as long as I can remember (even though I change every 3k, I don’t put on a lot of miles), definitely at least for my last three changes, as I still have the jugs of old oil on my workbench.

I found out the hard way a couple of years ago that my engine burns oil, so I check it every time I get gas (about every two weeks) and try to keep it in the middle of the SAFE range on the dipstick. I know for sure that before I changed it last weekend, I was at least a quarter of the way into the SAFE range. After refilling the engine with 6 quarts of oil and letting it run a minute to fill the filter, the oil level is in the dead center of the SAFE range. So the dipstick is showing me less than a half-quart difference between pre-change and post-change levels (assuming the entire SAFE range on the dipstick is 1 quart).

However, as I’ve said, when changing the oil I only get 4.5 quarts out. Here’s what I do: I open the oil filter cap so the crankcase can ventilate, drain the engine until it’s a slow drip, change the filter (emptying it into the drain pan), and refill. Then, I pour the oil from my drain pan into the 5-qt jug the new oil came in, and this is where I lose my mind, as the level indicator on the side of the jug shows me only filling it to 4.5 quarts.

So, what the heck is going on? I know there will be residual oil in the engine, oil pump, filter housing, and drain pan itself, but will all that really add up to 1.5 qts?

Edit: I just had another thought. When I’m checking the oil while getting gas, the engine is completely hot, showing the oil level as high as it could possibly be. Then, after changing the oil and letting the engine run for just a minute to fill the filter, the engine isn’t hot at all, showing the oil level as low as it could possibly be. That probably has something to do with it, but still, 1.5 quarts?