All,Thought I would post a thought I had that goes against what everybody does:Conventional wisdom and recommendations say to change your oil after you have brought the engine up to temperature. The idea is that all the particulates that have settled in the pan get mixed up into the oil so that when it is drained you get a cleaner result. The problem with this is that the oil is dispersed throughout the engine in all the oil-ways and up in the rockers, etc. So theoretically, the most "complete" oil change is done after the engine has sat for an extended period of time giving all the oil a chance to make its way back into the pan. (I don't think I have ever changed oil and had the old oil stop dripping out the drain hole.)Now, on to the sediment issue....a while back, after an unfortunate event, (a story for another time....) I had to drop the oil pan on my Cat C7. The rig had been sitting for weeks without being started. I drained the oil and dropped the pan. I was half expecting to find some thick sediment in the bottom of the pan, but to my surprise it was sparkling clean with just a thin layer of oil in it. So, in light of this, it made me wonder if it is not better to do oil changes on cold engines? Running the engine just disperses the dirty oil of which some doesn't get drained. What do you think? If you abuse your oil and don't change it regularly, then the sediment/crud issue could be a valid argument.BTW, I have been doing all of my yearly maintenance and just changed the oil today. What did I do? Ran it around the neighborhood until it was hot and then changed the hot oil! Hard to stray from old habits.I would be interested in hearing others thoughts on this.Regards,jeff

After warming up the eng, I let it sit for 10~30 minutes so it drains thoroughly.

why would anyone want to get the engine hot and then try and drain hot oil and hot oil filter ?? answer no one so not sure where your coming from? second off why would u think you would have had sludge in your C7 oil pan?

I used to drain the oil cold, thinking the same thing as you..But, after doing it that way for several years with my old 86 Mustang GT 5.0, I found the dripping would take longer and longer with more of a stringy type of stream.. Not really a drip any longer..Also, I started to notice the oil would get "black" a lot sooner after the oil change too..Started warming up the engine first after that. I would warm it up, let it sit maybe 10 minutes, just so the exhaust pipes would cool down some and then let it flow..Not only did it flow out much faster, it flowed out smoother, and would drip again after a short time and never that stringy drip anymore.Started to notice the oil keeping it's color longer too..So, been warming up the engine first ever since than.Just my experience with it.. No idea if it makes ANY difference at all, but I feel better about it and since it's my vehicles, that's what I do.. :)Good luck!Mitch

gutfelt wrote:why would anyone want to get the engine hot and then try and drain hot oil and hot oil filter ?? answer no one so not sure where your coming from? second off why would u think you would have had sludge in your C7 oil pan?The vast majority of oil changes are done on warm engines - just as the manuals generally dictate. Personally, I've never found the oil to be so hot that it was a problem. Being hot, the oil drains quicker, more thoroughly and the filter is easier to get off as well.

I change oil when cold or maybe warm if it happens to be. I don't warm up the motor to change oil. Change on miles only, not time.

A thought that goes against the norm! | Good Sam Community

tropical36
Explorer
Dec 01, 2017
Spizzer wrote:
All,

Thought I would post a thought I had that goes against what everybody does:

Conventional wisdom and recommendations say to change your oil after you have brought the engine up to temperature. The idea is that all the particulates that have settled in the pan get mixed up into the oil so that when it is drained you get a cleaner result. The problem with this is that the oil is dispersed throughout the engine in all the oil-ways and up in the rockers, etc. So theoretically, the most "complete" oil change is done after the engine has sat for an extended period of time giving all the oil a chance to make its way back into the pan. (I don't think I have ever changed oil and had the old oil stop dripping out the drain hole.)

Now, on to the sediment issue....a while back, after an unfortunate event, (a story for another time....) I had to drop the oil pan on my Cat C7. The rig had been sitting for weeks without being started. I drained the oil and dropped the pan. I was half expecting to find some thick sediment in the bottom of the pan, but to my surprise it was sparkling clean with just a thin layer of oil in it.

So, in light of this, it made me wonder if it is not better to do oil changes on cold engines? Running the engine just disperses the dirty oil of which some doesn't get drained.

What do you think? If you abuse your oil and don't change it regularly, then the sediment/crud issue could be a valid argument.

BTW, I have been doing all of my yearly maintenance and just changed the oil today. What did I do? Ran it around the neighborhood until it was hot and then changed the hot oil! Hard to stray from old habits.

I would be interested in hearing others thoughts on this.

Regards,

jeff

Had this same thought and changed one cold. Not that it's what you call cold, in the tropics. Then with reading some, I got talked out of it. After reading all the posts in this thread, I think I'll go with a cold engine, this next time, which will be pretty soon and with trying out my new low boy draining cart.
I could always use the block heater for a few hours in the morning, if need be and since I don't do much these days, until after lunch, anyway.
gutfelt
Explorer
Nov 30, 2017
wyocamper wrote:
DSDP Don wrote:
Heck, I live in California and change my oil usually in early May. Everything is already 80 degrees when I start my coach service.

Doesn't really matter if it's 20º or 120º outside when you start, if it sat over night then the engine and engine oil are still cold.

well if its 60 degrees out its hardly what I would call cold and plenty warm for oil to drain properly
Chum_lee
Explorer
Nov 29, 2017
For those of you who think that soot regularly settles out of the oil or gets trapped in the oil filter, clearly, you've never taken apart an engine made within the last 30 years that has been reasonably maintained.

The reason the oil gets black in the first place is because the soot particles remain suspended in the oil. (by design) Google "oil dispersant" and learn what they do (and how they work) in modern oils. Soot particles are are sub micron in size. (30 microns = .001") Most quality OEM oil filters are good to about +-30 microns (or about .001"), no more, unless you buy a super premium oil filter (like Mobil 1 which are good to about 10 microns) which simply, isn't needed in most automotive applications. Soot particles are far too small to be filtered out by resin impregnated pleated paper oil filters which is WHY the oil once black, stays black. Todays oil dispersants are designed to keep soot particles from agglomerating (growing in size) and to remain suspended in the oil. Soot particles are far smaller than the tightest clearances in most modern engines until the dispersant additive becomes saturated. It's at that point where the sub micron particles can begin to grow causing engine damage and plating out like paint on internal engine surfaces. That, among other reasons, is why you need to periodically change your oil. If you see sludge forming inside a modern engine, its because the oil is breaking down and combining with soot to make a nasty sticky mess.

Chum lee
Terryallan
Explorer II
Nov 29, 2017
chuckftboy wrote:
doc brown wrote:
Old-Biscuit wrote:
Bruce Brown wrote:
We may be over thinking this. When was the last time anyone actually found sludge in a modern engine?

Use a good quality oil and filter, change it at a reasonable time, and enjoy many, many trouble free miles.

LOL....

RVrs have a tendency to make 'things' complicated

:B

Exactly. Like the thread sometime ago stating that if you wax your coach too often you'll decrease the mpg.

Yeah, we all know the more we wax them, the better they slip through the air, increasing mileage. LoL!!!!

Inn truth that last part is true. Vehicles do slip thru the air better when waxed. NOTICE NASCAR crews wax their cars right up to the qualifying run to get the most speed out of them. Air crews would wax the fighter planes to get the most speed out of them. waxing a vehicle cuts down on drag. Less drag = better performance, and higher mpg.
OH48Lt
Explorer
Nov 29, 2017
It's a non-issue. Hot, warm, or cold, it doesn't matter. Just use a quality detergent oil, like most oils these days. You're going to get the same amount of oil and particulates cold or hot, the filter comes off the same cold or hot, and shouldn't be any sludge left behind, cold or hot drain.

30 years ago the answer would be different.
chuckftboy
Explorer
Nov 29, 2017
doc brown wrote:
Old-Biscuit wrote:
Bruce Brown wrote:
We may be over thinking this. When was the last time anyone actually found sludge in a modern engine?

Use a good quality oil and filter, change it at a reasonable time, and enjoy many, many trouble free miles.

LOL....

RVrs have a tendency to make 'things' complicated

:B

Exactly. Like the thread sometime ago stating that if you wax your coach too often you'll decrease the mpg.

Yeah, we all know the more we wax them, the better they slip through the air, increasing mileage. LoL!!!!
wyocamper
Explorer
Nov 29, 2017
DSDP Don wrote:
Heck, I live in California and change my oil usually in early May. Everything is already 80 degrees when I start my coach service.

Doesn't really matter if it's 20º or 120º outside when you start, if it sat over night then the engine and engine oil are still cold.
DSDP_Don
Explorer
Nov 28, 2017
Heck, I live in California and change my oil usually in early May. Everything is already 80 degrees when I start my coach service.
4x4van
Explorer III
Nov 28, 2017
Some interesting theories, on both sides of the aisle. I particularly like rgatijnet1's idea of pouring an additional quart (or 2) through a drained engine and letting that drain also, before replacing the plug. Might actually "collect" some additional crud on the way through and expel it from the engine, at a minimum of cost.

Personally, I drain when cold, or occasionally warm, but never hot. There is nothing enjoyable about hot oil, drain pugs, or filters, nor trying to manipulate them around hot engine parts. In fact, the older I get, I refuse to work on a hot engine, unless it is absolutely necessary from a troubleshooting standpoint. And the ONLY times I've ever had problems removing a filter, hot or cold, is when some other idiot installed it too tightly in the first place. Tightening 3/4 turn after contact (which is what every filter out there says right on it) it perfectly doable by hand; no tools needed. Step away from the filter wrench!

My current class A has plenty of room to get to the filter, but the first oil change, just after purchase, convinced me that some people should never go near mechanical things, ever! It was so tight that several styles of filter wrenches failed, and even a large screwdriver through the side did not work; it just ripped the filter in half! Luckily, there was just enough room to get a chain wrench wrapped around the half that was left, and even then it took a full 1 1/2 turns using an 18" breaker bar before it finally loosened enough to spin off!
Spizzer
Explorer
Nov 28, 2017
newman fulltimer wrote:
i use a magnetic engine heater on the pan warm the pan and drain it

Ahh! The best of both worlds! Hadn't thought of that.

jeff

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