Changed my oil the other day and... I only was able to remove 4 quarts.

[07 Boss]

Oil wears out and gets dirty. 7 quarts last longer than 6 quarts.extra margin of safety if you get an oil leak. What kind of bad things. 46 years, over 40 vehicles, and 1.4 million miles driven, says bad things don't happen.

Well a single qt will probably make no difference but overfilling the oil can lead to cavitation with the crank and then loss of oil pressure. What I meant was that I don't think there is much advantage or benefit and having extra oil may cause issues. If the oil is getting dirty or worn out, change it. I change my oil much more often than most because I don't run a PVC system. I get more fuel and junk dissolved in my oil which breaks down the viscosity quicker. I go about every 3K-4K between changes.

 

[Laga]

Although it’s rare, I’ve had two vehicles get oil leaks from road debris and another from a faulty oil pressure sending unit while driving. It only takes seconds to toast a oil starved engine. Like what happened to my friends 04 BULLITT when his son didn’t see the old oil filter gasket stick to the block. Sadly, the kid thought the smoke that was being created was from spilled oil and not leaking oil. The extra oil gives you extra time to react to a problem. I never said to fill up to the point of causing cavitation and an extra quart in a V8 does not cause this. I really don’t know why some of you are getting so upset. There are dozens of examples of things that are “known “ to be facts about cars and engines that just aren’t true. I’m not telling anyone to do this. The OP was worried over nothing and I was trying to tell him it’s ok. There is a little wiggle room built into fluid levels. If there wasn’t, there would be hundreds of thousands of dead cars on the side of the road. BTW, I change my oil every six months. Which is about 1500 miles.

 

[GriffX]

Hard to believe that after 20+ years of oil changes I can still get confused....

Did a cold oil change and let the drain plug open for days, pre-filled the filter, added 6qt of Shell Helix 5w30, after 15 minutes the level was at the top of the crossed area. Cranked the engine in clear flood mode for 10 seconds, let it rest for 10 minutes and the level sunk down to 2/3 of the crossed area. Can probably add 0.2 or more oil.

In chemistry the pipettes are calibrated for a 10 second drop out, after that you have more volume as you wanted. looks like the engine oil volume is similar

 

[WJBertrand]

I’ve never had any issue just adding the quantity stated in the owners manual. Brings it right to the full line.

 

[GriffX]

I’ve never had any issue just adding the quantity stated in the owners manual. Brings it right to the full line.

Me too..... Now it is getting interesting. I added 6.5qt and I'm not at the full line. Car is on level ground, engine is stock 2007 4.6. But, I noticed it was dripping even after 24h, around one drip per minute. Got ~5.9qt out of it + the oil in the filter. The level at the stick was 3/4 full.
The engine rebuild oil capacity must be more than 6qt, I don't have any other explanation for this right now.

 

[Pentalab]

I’ve never had any issue just adding the quantity stated in the owners manual. Brings it right to the full line.

I add 6 qts in my 2010..and right up to the full line. On a related note, between the low line....and the high line is exactly 400 ml. (.422 US QT).

 

[GriffX]

I add 6 qts in my 2010..and right up to the full line. On a related note, between the low line....and the high line is exactly 400 ml. (.422 US QT).

Good info, with the 6.5qt I'm now 2 of this crossmark lines below full. I added 0.05 more now, I guess it is full now, will see tomorrow. Pretty sure now that there is some dead volume which you usually not drain out, except you let it open for a day. Maybe oil creeps backwards through the oil pump, or so?

 

[WJBertrand]

I add 6 qts in my 2010..and right up to the full line. On a related note, between the low line....and the high line is exactly 400 ml. (.422 US QT).

I have the Coyote 5.0 which takes exactly 8.0 qt. to reach the full line after an oil and filter change.