The original question is hot vs. cold.....Blackstone recommends "warmed up" engine oil sampling.....last sampling I took, I took a drive to and from the store for grocery getting, got home, unpacked the groceries, then got out my MixMizer Pump
and had at it, through the dipstick tube
That link/post is quite lengthy with commentary though but I basically used the mixmizer, an ice maker kit, and a pliers to crimp off a length of the ice maker tubing.....I basically gave my self "twice" the length of the dipstick length....and of course, made a sharpie mark at the end of the dipstick, so I'd know roughly where/when the tube "hit oil"
Took maybe 2-4 pumps to fill the Blackstone test container
And yes, the sample Is still sitting on the shelf :X haha.
But yea, the biggest problem seems to be the oil within the pump....the oil has complete contact with the syringe, tubing, etc.....so the "pros" may not like this approach :P Since you're sort of "cross contaminating" the oil sample, if there were left over residue left in the pump.....but really, how much can be left????? After soaked in gasoline for 5 minutes, blown dry with compressed air, then washed with simple green and water.....? Really? That big of a deal to worry about? I'm not "fretting" over it really....hehe. I do know, the syringe will be "dry" and not "smell" of gasoline at least, next time I use it
Since I essentially let it "hang dry" and "air out" after the simple green route...only thing I replace is the ice maker tubing.