Originally Posted by Duffyjr
Originally Posted by PimTac
On the other hand, draining it hot also means stuff is suspended better so you might be getting more stuff out that would otherwise build up inside.
I have to ask where do the contaminants go when the oil is cold? As the engine cools and the oil drains back to the pan do the contaminants get left behind. Just trying to wrap my head around this because I don't change my oil any longer so when I take it to the quick lube the oil is warm but when I leave it with my mech it's usually the night before so I know he's not letting it warm up so if this is an issue I might consider going back to the quick lube.
I have said this several times here.
I don't understand the argument to change hot because of contaminates being suspended better. What contaminates?
Filters are there for a reason, to filter out contaminates (the size of them will vary depending on the filter, from 50 to 20 microns), and the oil holds whatever is left in suspension. Nothing to come out of solution.
If you have contaminates that you are worried about if changing oil hot vs cold, something else is majorly wrong with your engine.
Also, if changing hot, more oil is up in the upper parts of the engine still vs cold where everything has drained down already.
I do agree that warm oil does drain faster than cold, but not by much.
Hot or cold, it really makes no difference though over all.
I agree that 50 years ago, it may of made a difference. Just as running a qt of ATF in the engine 50 years ago was acceptable and helped clean due to the poor quality of oil and filtration then, but not today (even though you have many that say to do it still).
I change it cold because I don't like burning myself on hot oil or engine parts.