Ok, I was thinking on the way home ( a scary thought) about why is there a need to warm the oil before draining for an oil/filter change. If it is simply because it will drain faster and easier then draining the engine after sitting for a day or weeks should not matter other than the oil may drain a little slower due to not being warmed up. Additionally, I would think that draining the engine while stone cold would remove all of the oil and contaminants since no oil is sitting in the filter (ok a little in the filter) or anywhere in the engine.

 

Conventional wisdom is to run the engine first then change the oil. All your points are valid, but if its cold out side you can keep your hands warm!

Seriously, I've always been told its to mix the oil up before you drain it.

 

Always change the oil after fully warmed up. I prefer after a long drive. You want all of the "bad stuff" fully mixed into the oil so that when you pull the plug it all comes out with the oil. When the oil has sat for a while, in theory the bad stuff can settle out to the pan and not drain with the oil. Of course the downside is everything is hot. My preferred method is to pull the drainplug at night and then change the filter when cold in the morning.

Regarding the filter - since our filters hang straight down, there is almost no difference in the amount of oil in the filter warm vs cold. And you change it anyway.

 

My current truck has nerf bars and it is too low to the ground for me to crawl under easily. I run it up on ramps to change the oil. That's all the warm-up I intend to give it prior to oil changes. The first time I changed the oil, I warmed it up fully and I wasn't careful in removing the filter. I got a hot oil bath.

 

I punch a whole in the bottom of my filter to keep from bathing in hot oil.

 

If the truck is left to sit overnight, their is enough drain back from the filter that when you remove it there are no spills, i slip a plastic bag over it just in case but so far not a drop on anything, including me.

rob

 

draining while oil is warm keeps all contaminants and particles in suspension, in english all of the junk is floating in the oil. What I do is drive the truck, drain and refill the oil, then wait until the next morning when it is cold to remove, refill, and install the filter. no burns, less mess, and I do use the bag method.

 

So I guess there is no hard and fast evidence about draining the oil hot or cold. Warm oil would make sense as to getting the contaminants floating in suspension thus ensuring they make their way out of the oil pan. Also, draining the motor while cold still seems to make some sense with the exception being the contaminants may (or may not) stay in the bottom of the oil pan.

Dang, I wish this thought had not entered my mind cuz now it is really bugging me..................................

 

Oil is kinda thick compared to water, beer and bourbon. Stuff floating around in oil is likely to stay suspended for a long time, whether it's hot or cold. Any liquids mixed in the oil are part of the solution and not very likely to separate easily. I also look at my oil pan and see that the drain plug is flat and the pan has an indention to accomodate it. This indicates to me that there will be some amount of dirty oil remaining in the pan after draining it.

Considering all these factors, I don't really think it makes a hill of beans which way you do it as long as you do it.

 

Does not have to be warm, it just needs to be run a bit to get all the contaminants to suspend in the oil. I usually drive it around the block and then proceed with oil change. This way its not to hot to work on.

 

i could be wong but if you let it sit the oil will have settled at the bottom which means parts of the engine are not pretected on the next start up, to where as if you warmed it up all the oil would cover all the engines parts well lubercated just my .02

 

My favorite so far.


I wear rubber surgical gloves. When I get the filter off, I hold it by the end and I pull the glove off and stretch it over the open end sealing it. Works pretty slick.