Hot.
Oil Change - Hot or Cold
- Thread starter dradave
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i've done it both ways myself
if its cold i just let it drain longer thats all
if its cold i just let it drain longer thats all
Ive always been worried about pouring cold oil into a hot head, so I wait till the valve cover is just warm to the touch
Originally Posted By: HM12460
hot! just like my girl friend.
Ummmm...if your going to post statements like that
you'd better be able to back it up with pic's...and lots
of them!!!!!!
hot! just like my girl friend.
Ummmm...if your going to post statements like that
you'd better be able to back it up with pic's...and lots
of them!!!!!!
If it was a cold start, cold shutdown, the oil is still thick enough that it may not drain in "5 minutes", plus, I'd rather have as much of the contaminates in solution as possible...as a general rule, liquids dissolve solutes more readily at higher temperatures. My guess is oil acts this way on contaminants.
Cold, after it sits over night because all of the oil had time to drain down into the pan, and only has to drain from 4 sides (pan), not from the entire engine (many sides). I know it is common to do it when hot, but I don't like to burn my self when removing my filter.
So drain the oil hot to get more crud out and then change the filter after it drains so its had time to cool down. Just in case there is sludge I would want it to be hot so it has a better chance of flowing out with the hot oil.
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Don't synthetics drain well when cold? Do you preheat your oil before dumping it into the engine?
I've done it both ways. Prefer doing it hot, like everybody says you should.
Not sure it matters a great deal anymore.
In the old days, poorer grade base oils might(might) drain off the cylinder walls and bearings overnight even if the galleries, etc. still had oil on them.
Modern oils leave enough barrier lubrication behind that's not the problem it once was.
With thinner oils, oil flow during and after starting is quick, so bearings get oil in a second.
Still, old habits die hard. I prefer doing changes hot.
Not sure it matters a great deal anymore.
In the old days, poorer grade base oils might(might) drain off the cylinder walls and bearings overnight even if the galleries, etc. still had oil on them.
Modern oils leave enough barrier lubrication behind that's not the problem it once was.
With thinner oils, oil flow during and after starting is quick, so bearings get oil in a second.
Still, old habits die hard. I prefer doing changes hot.
Triple_Se7en
$50 Site Donor 2024
Hot oil.
It takes longer to drain when cool/cold, but an important advantage is that the oil has had time to drip down into the pan, and you also won't get burned.
This assumes the car was sitting before the oil change - if it was started and driven to the place of the oil change, then warm/hot is better.
This assumes the car was sitting before the oil change - if it was started and driven to the place of the oil change, then warm/hot is better.
I change it both hot and cold.
I have a pad heater on the oil and transmission pan.I plug them in for about 3 hrs and drain the oil with the engine still cold,so far it seems to work pretty well,my OC needs almost 1/2 qt more than the regular hot and 15min drain method.
I have a pad heater on the oil and transmission pan.I plug them in for about 3 hrs and drain the oil with the engine still cold,so far it seems to work pretty well,my OC needs almost 1/2 qt more than the regular hot and 15min drain method.
I got an idea. Since this topic has not referd to any scientific studies that prove one or the other way is best, if you do it hot at one oil change then cold at the other, you could only be half wrong. Right??
I have always done mine hot. I have a scar on my left arm when I brushed the inside of my forearm against the hot cat. Hurt pretty bad but it was all my fault and I am of coarse more careful now. But there are some good arguments now about doing it when its cold. I usually go and dump my old oil and buy fresh and just come home and do the oil change. So just the driving it up to the store warms it up pretty good.
Originally Posted By: RWEST
And, just to be different, an old mechanic told me one time to drain when it's cold, especially if you have a magnetic drainplug. He maintains that anything that is in there will have settled to the bottom of the pan after an hour, minimum, of cooling, so all the crud will come out. According to him, running the engine causes all that stuff to be swept loose and re-distributed throughout the engine, otherwise.
Really, you must have one of those old engines that have no oil filters. I would expect the oil filter to catch most of the debris floating around, before it makes it into the journals and other passages.
And, just to be different, an old mechanic told me one time to drain when it's cold, especially if you have a magnetic drainplug. He maintains that anything that is in there will have settled to the bottom of the pan after an hour, minimum, of cooling, so all the crud will come out. According to him, running the engine causes all that stuff to be swept loose and re-distributed throughout the engine, otherwise.
Really, you must have one of those old engines that have no oil filters. I would expect the oil filter to catch most of the debris floating around, before it makes it into the journals and other passages.
Based on another member's findings in an old oil sample bottle, I would definitely change the oil when it's hot or at least well circulated.
i'm gonna try it cold and see if more comes out. makes sense
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