Warm up before oil change?

Cold engine. Pull the tank.

All:

Running the engine for an oil change is the recommended method.  Normally you are not just doing an oil change, you are completing an annual or some other work.  Most pros I know will do the visual checks first.  This is done with a print out of any relevant SB or ASB and see if any need compliance in the log book.  The warm engine is essential for a cylinder leak-down test.  You need to verify ignition drop and fue pumps and a host of items.  The list goes on and combining tasks just makes the whole job go smoother in my view.  There is no question that warm oil will drain faster from the oil tank also, another plus.  The check list is for you to ensure that all the items get covered, it does not have to be in order, do what makes sense for time and best use of tooling. 

I would recommend that some visual checks be done after the engine warm up also.  Things like checking the vent lines for fluid build up and looking for drips from your water pump.  You are going to run it up regardless so why would you want to do a cold oil change?  I really do not see any added value to that idea. 

My opinion as always. 

Cheers

No doubt in my mind warming up an engine to full operating temperature before changing the oil.  We want to suspend as much contaminant in  the oil before dropping it.  Have you ever poured used oil into a clear container and emptied the container later?  There is noticeable amounts of material that has settled to the bottom of the container even on engines that have the oil changed regularly.  It does the same in the bottom of the crankcase and any collection points in the engine like the bottom of the ignition housing and below the mag plug hole in the gear box.  Changing the oil cold when you're in a bind once in a while is no issue, but definitely not a good standard practice.

I see no appreciable increase in the amount of oil drained hot or cold.  You should be burping the engine oil immediately before draining the tank anyway.  Just my .02 from a long time technician.  And the manual says to do so. :)           

The question of hot versus cold oil drainage time intrigued me. As a chemical engineer, tank drainage times are a routinely calculated effort, and obey regular rules for calculation drainage times when the tank has liquid in it. Once the drain line becomes empty, there is some further draining off the walls of the tank over time, but there aren't any routine calculation methods for this I've run across in my 60 year career. What's worse, the good old Reynolds number starts to apply, as it lowers as the layer on the walls of the vessel thin down. The liquid on the walls drops from turbulent to laminar flow as the last bits of liquid drain out. 

Higher temperatures lower viscosity, which helps keep the liquid sliding down the wall more turbulent for a longer period before becoming laminar flow. Turbulent flow should scrub the tank walls better, getting out more of the sludges and anything else attached to the walls. Once the flow goes laminar, the remaining sludge will tend to remain in position longer. 

I would drain the oil out of the aircraft as hot as I could stand it.  

Even if every drop isn't drained from the tank or you wipe every drop out you still have old oil throughout the engine. You never remove all old oil.