Hot. As stated above, it allows for more of the suspended particles to drain. Long ago, I started using these gloves when changing oil:

https://www.homedepot.com/p/We...3500-LLCW9/202192535

They're lined, and thick enough to protect against hot oil. Also gives a good tight grip when tightening oil filters "Hand Tight".

I use Mobil One, so it's going to drain the same whether cold or hot.

You can do two things to get all the old oil drained.

Let the oil drain overnight.
Pour a quart of cheap oil into the filler tube after removing the drain plug.

As for me, I let the iol drain overnight if possible.

Neither hot nor cold, but "quite warm."

I run the engine until it's up to operating temperature, then let it sit long enough for the all the oil to get back down into the pan and to reach "won't burn me" temperature. Then I let it drain until the drips stop.

Gave up changing mine when they started putting shields on the bottom of the car. I can have it changed for little more than I'd pay for the components and they use Mobile One.

I change the oil in the bike and the manual specs warm. Getting it up to normal operating temp isn't needed.

Your oil filter is for particulates. The primary reasons for changing your oil are degredation of the oil, and acid buildup in the oil.

When you run the engine prior to the oil change, you're picking up any residual oil and acid that's drained off the case walls with condensation, and circulating it before removal. If you're doing an oil analysis, run the engine, start the oil draining, and don't catch the first oil that emerges; get it mid stream, otherwise you'll be collecting sediment near the drain plug and will contaminate the sample.

Warmer allows the oil to drain more freely and removes most of the acid present.

I prefer warm, but I'm not going to make a special trip just to warm it up. If it's been sitting before I go out tochange it, I have no problem changing it cold. It drains a lot faster when warm, though.

quote:

Originally posted by sigmonkey:
Warm.

I let it sit for about an hour.

+1. Usually after work. Long enough not to burn myself on the exhaust.

quote:

Originally posted by Balzé Halzé:

But does it really matter otherwise? No, not really.

It might have mattered more for older / non synthetic oils.
Anything but stone cold for me. Don't worry about it much.

You can only vote once, so even though I don’t change the oil in my own cars anymore, I voted the hotter the better. It is possible that you’ll better suspend the gunk and get more of it out, but my reason was always impatience. Warm oil drains a lot faster. However, depending on the orientation of and access to the filter, removing that while hot can be unpleasant...

Engine warmed up for about 10 minutes (around the neighborhood a few times) back to the house engine off. Get set up, car up, tools out, oil and filters set up. By then the oil has mostly drained back to the pan and the filter isn't overly hot. Plug and filter off for about 5 minutes. After the change mash the throttle to the floor and turn key on, this keeps the the engine from starting (at least my Mustang) and pumps the new oil in the engine and fills the new filter. Then start it up and take it out for a drive.

The hotter the better. Best right after driving on the freeway. You get much more crud and old oil out when changed HOT. I was a professional mechanic for decades, both gas and diesel.

Usually I will start the oil draining, then go back later to remove the filter after it has cooled down. On my old Ford van, I would sometimes change the filter after a complete cool down, to reduce drips from the oil filter.

I will often put in a pre-oil change flush which I think is some sort of diesel concoction leading to a "warm" but not hot after running it for 10 minutes or so.

I time it after a normal drive, preferably on a day with nice weather.

I voted "hot" but only aim for "warm" I always manage to get at least a little on my hand even with gloves.

I prefer warm, but I wouldn't put off an oil change just because you're stuck doing a cold oil change.

I change it warm because I don't have patience to wait for molasses to drain and hot oil burns.

Warmish I’m pretty sure the suspended solids are continuously removed by the filter, I simply want the stuff to vacate quickly.

I’m not interested in a pencil stream of oil blowing all over hell and gone while I either lay there or sit in the garage drinking beer.

I’ve seen enough empty oil pans, valve covers, and lifter valleys to know that hot or cold the shit drains just the same. Stuck nasties remain until you pry them out with a stick. I’ve got better shit to spend my time worrying over.

As has been said, warm. It drains better and more completely.

Getting scalded by hot oil is a thing of the past if you install a drain valve, such as Fumoto.

quote:

Originally posted by GaryBF:
Getting scalded by hot oil is a thing of the past if you install a drain valve, such as Fumoto.

I put one of those on last year and I love it.