Just let me know how much less oil you think would come out of an engine that hasn't been run all day on a 50* day, as compared to one that had been properly warmed up first.
I'd like to know how much would remain in the pan. Thanks

 

if you let it drain long enough not much. there's more to it than just the temp of the oil

 

well I did a cold oil change against my better judgement (time factor) on my father's truck, and only half the reccomended amount came out including filter. The oil that was in there was 10w-30 wally world synthetic (quaker state) with 6k miles on it. I am just wondering if there was any damage done. I hope no one turns this into another "oil vs. oil" debate, that is not the original topic, it's not my truck, I didn't choose that oil, and new oil is already in the truck.

 

Start looking elsewhere for the problem, you're either leaking it or burning it out. Depending on what the vehicle is used for, as much as 1.5 quart every 3000 miles is considered acceptible be most manufacturers though, so if it's a 6 qt pan it's right about where it's supposed to be if it's a HD truck. If he never lost oil before though, there is most likely a problem. If it's always done it, have him top it off every time he stops for gas.

If it's a SBC, it can be ran down as low as 1 qt before serious damage will result. Not good to do though, the oil will run at a much hotter temp, causing it to not lube as well, and drive up the operating temps of the motor.

 

the underside looks spotless, there's no seepage. It also doesn't smoke at all. I don't know if it's used oil between intervals before, this is the first time I worked on his truck. But yes, according to the 1.5qt/3,000mi oil consumption rate, I guess it's not a problem if at 6,000 he's that low. Thats still weird though, I've owned quite a few vehicles, and granted, I do oil changes at 3k miles, but the only thing thats ever used oil nearly that fast is a Harley, even after assuming the oil has been diluted with gas. Thanks for the input.

 

I get weird about certain things, but I always check the dipstick before I start draining the oil.

"...only half the reccomended amount came out including filter" isn't very quantative. Are you saying 2-1/2 quarts, 3 quarts, 2 quarts - what?

I've seen more hang in the filter than in the engine. FWIW, when cold, there's more in the pan than there is hot (mass-wise, not necessarily volume-wise). It takes a little time for all of the oil in the top-side to drain down. If you let the oil drain until it wasn't dripping, the fact that it was cold is irrelevant.

Another tidbit: You don't drain all of the oil out of the pan whether cold or hot, regardless of how long it drains. The drain plug threads into a nut, which sticks up into the pan. Gravity will not take the oil below the nut over the top of the nut. (FWIW, this is why products such as Slick 50 "last" 50k miles. Most of the PTFE sits in the bottom of the pan, a little is stirred up and picked up by the pump during operation; when drained, this last little puddle of oil that doesn't drain out still has the PTFE in it.)