Changed my oil drain method!

One thing you mentioned about the contaminants yes they are in the bottom of the sump but they won't come out through the drain plug unless they are dispersed

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I usually run the engine a few minutes to mix the oil a bit before draining. Then I leave the drain plug open when changing filter and doing some other tasks. I don't think it is that critical.

 

Won't disagree that changing the oil full hot is a terrible experience to be avoided (I prefer to do it just warmish and then after rerunning for a minute, or two, to stir it up right before draining and better suspend the junk up into it as Dominick and conan indicated), but did you make a typo or misread a chart? Cold 0W40 (20 deg C) is more like 150-200 cSt per the references that I've seen:

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and any cold oil having a lower viscosity than the same oil hot seems downright magical?

 

I flush with clean oil with the drain plug out to pick up some of the deposits in the sump until the oil flows “clean”.


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Mike, I'd have to agree with Steve and suggest that you've perhaps misread a data sheet - there's no way cold 0W-40 is thinner than hot 0W-40.

I do agree with draining cold, though, because there's a greater volume of oil sitting in the sump after a few hours of sitting than just after running. We want as much of the old oil as possible to come out, not to have a small quantity dispersed through the engine.

The wet sump bottom of the 308's V8 isn't flat, and the drain plug isn't the lowest point - it's the lowest point of it's segment directly under the oil pump pickup, but the segmented/compartmentalized bottom has low spots that don't connect to the compartment around the drain plug for the bottom few mm of depth - so any theories of running it hot to suspend the sludge to drain don't pan out in practice. I installed the additional anti-surge sump baffle (which prevents oil pressure drop and oil starvation in hard right cornering) last fall in my QV, here's the oil pan straight after removing:
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You can see the drain plug in the larger square bottom part, just left of the middle. I've owned this car for 7 years, and it's run synthetic for that entire period, but there's still a good amount of sludge settled on the bottom that simply never gets circulated back into suspension or drained by hot oil to the drain bolt.

A closer look:
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If you want all the thick deposits out of the bottom of the oil pan, this is the only way to achieve that!
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(Here's two photos showing the anti-surge baffle and the sump with it installed):
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Cartman method....
Suck it out with a hose

 

Don't see why this is an issue -- unless you want to immediately put the drain plug back in. Running it and then letting it drip overnight from both the drain plug hole(s) and the oil filter mount gets out even more oil volume than draining it cold and immediately putting the drain plug back in.

 

Very true, with that "unless you want to immediately put the drain plug back in" qualifier. I rarely leave the plug out to drain overnight on any of my cars, the most drain time they might get is 60 minutes max, more like 30 min. Honestly, though, I don't think draining hot or cold makes much difference - unless you're going to suck it out as Scott suggested, then the thinner viscosity hot oil makes a big difference in speed of extraction!