Car Filter: Slightly too much oil?

September 25, 2006 5:17 AM

How bad is it to run an engine with slightly too much oil?

Changed the oil and filter in my 2001 Mercury Villager, added approx. 4 quarts half-synthetic. Ran engine, checked oil, just barely within the 'hashmarks' on the dipstick. Then I added approx. .5 quart and it is slightly off the top of the hashmarks. Enough to worry about?

posted by toastchee to travel & transportation (6 comments total)

The Car Talk guys say too much oil can be a big problem: "If the oil level gets high enough so that it touches the crankshaft, the oil will get whipped into a foam." Less than half a quart over the mark is below the amount they recommend worrying about.
posted by sfenders at 6:16 AM on September 25, 2006

Enough to worry about?

Probably not. I've seen a lot worse.
posted by knave at 6:46 AM on September 25, 2006

Not to worry, but don't add more.
posted by caddis at 7:40 AM on September 25, 2006

sfenders, I imagine if this did start to happen you'd see the oil pressure light give indication of reduced pressure?
posted by toastchee at 8:21 AM on September 25, 2006

Sounds like the excess amount isn't enough to be concerned about. There is a fairly simple way to remove extra oil without draining the entire engine. You need a piece of tubing thin enough to fit inside the dipstick tube and long enough to reach the oil pan and a bulb syringe or a turkey baster. Duct tape the tube to the turkey baster and just suck out the extra oil.
posted by X4ster at 9:52 AM on September 25, 2006

you'd see the oil pressure light give indication of reduced pressure?

I expect if you had a proper oil pressure gauge it would register some difference, but whether it would be enough to trip the switch for a light, I don't know. The pressure reading alone wouldn't be perfect since you'd presumably have a mix of oil and air that's somewhat less useful for lubrication than just oil at the same pressure.

Seems like a pretty remote possibility, though. I imagine if an extra half a quart of oil were enough to do that, it'd happen all the time. In real life, not counting the internet, I've never heard of it.
posted by sfenders at 10:02 AM on September 25, 2006