Oil change with warm or cold oil?

[Oregoonian]

Originally Posted By: daman
Don't start it, the oil has already drained off parts and down into the pan nicely. Being it's cold it will require longer time to drain, if the car isn't needed right away give it time and let it drain a day or two.

Any moisture will be burnt off with the first drive.


+2....^^^^..totally agree with ^^^^^.

 

[wolfehunter]

I change oil and filter every 2 years in the Chevelle so the oil has been in it since April of 2014. We put less than 500 miles on it a year so I just change it every 2 years for peace of mind. Yes, the battery has been on a tender(out of the car) all winter and it has Stabil in the fuel.

As stated, I have always fired it up in the springtime after a winter sit and then changed the oil and filter. I was looking for opinions and definitely received arguments for both procedures. Sounds like it really isn't that big of a deal either way. Thanks for the suggestions.

 

[Oregoonian]

Originally Posted By: wolfehunter
I change oil and filter every 2 years in the Chevelle so the oil has been in it since April of 2014. We put less than 500 miles on it a year so I just change it every 2 years for peace of mind. Yes, the battery has been on a tender(out of the car) all winter and it has Stabil in the fuel.

As stated, I have always fired it up in the springtime after a winter sit and then changed the oil and filter. I was looking for opinions and definitely received arguments for both procedures. Sounds like it really isn't that big of a deal either way. Thanks for the suggestions.

Excellent conclusion! !

 

[spasm3]

I think hot or cold is splitting hairs.

Having said that, if the car is well maintained and the oil changed properly for the mileage/driving conditions, cold would probably be fine.

If the car has had sludge issues or neglected oil changes, changing hot may get some of the stuff out while its in suspension.

 

[deven]

It doesn't matter one bit. Car will last just as long either way.

 

[eljefino]

Good grief don't change it cold!

You're bringing it out of storage anyway and since it's a classic you'll have various misfires, sticky chokes, etc. Waste the old oil on it. I'd give it a good initial crank without pumping the gas/ setting the choke and hope that it doesn't actually catch right off.

Also your oil pump could have nearly lost its prime; doing a stone cold change on it could siphon out the old/ get an air bubble in there/ whatever. DON'T FLAME ME; IT HAPPENED TO ME on my saturn with a timing cover geroter pump somehow.

The oil that you left in there is "good enough" to get it running this spring, otherwise you wouldn't have left it in there. Even a somewhat depleted TBN is not battery acid that's going to eat your (blank) when you get it going, despite pearl clutching to the contrary.

 

[Chewie]

+1

Originally Posted By: hatt
I'd for sure drive it around to get it hot. Over 4-5 months of sitting a lot of stuff has fell out of suspension that needs to be mixed back up so you can drain it out. Look in the bottom of a jug that's been sitting with used oil if you don't believe me.

 

[Bamaro]

Take a drive to warm up the oil, then drain the oil right away, go have a beer go do something else for awhile while draining, then refill.

 

[dlundblad]

This seems worth experimenting with IMO. Drain the engine cold and measure what came out.. then do the same thing with a hot engine.

I've always drained them while hot and have never over-filled anything. Even with the little Kubota 3.5 quart sumps.

Speaking of tractors, anything sitting a while (or exposed to abnormal amounts of contaminants), I use a few times (mow the whole yard. etc), then drain while hot right after use.

 

[69GTX]

My owner's manuals don't tell me to whether to drain my oil hot, warm, or cold. From that I have to assume the difference has a minimal effect on engine longevity. Maybe it's 50-50, 52-48, or 48-52. I prefer a warm drain, but have done it both ways depending on circumstances.

 

[hatt]

Originally Posted By: 69GTX
My owner's manuals don't tell me to whether to drain my oil hot, warm, or cold. From that I have to assume the difference has a minimal effect on engine longevity. Maybe it's 50-50, 52-48, or 48-52. I prefer a warm drain, but have done it both ways depending on circumstances.
OMs assume you'll be driving to the dealer and having the oil changed hot.

 

[kschachn]

Originally Posted By: hatt
OMs assume you'll be driving to the dealer and having the oil changed hot.


So you are saying that dealers instruct their technicians to drain oil hot? It's not prescribed in any of my service manuals, FWIW.

 

[hatt]

Originally Posted By: kschachn
Originally Posted By: hatt
OMs assume you'll be driving to the dealer and having the oil changed hot.


So you are saying that dealers instruct their technicians to drain oil hot? It's not prescribed in any of my service manuals, FWIW.
Your service manuals don't instruct techs to let the car sit for several hours do they? By default they're going to drain hot if you come in for a oil change. The post wasn't a super serious post in the first place. Just illustrating that reality dictates hot oil changes.

 

[kschachn]

No not at all. Reality is reflected by them but not dictated, you jumped to an unwarranted conclusion.

 

[hatt]

Originally Posted By: kschachn
No not at all. Reality is reflected by them but not dictated, you jumped to an unwarranted conclusion.
What is your point exactly?

 

[kschachn]

Originally Posted By: hatt
Originally Posted By: kschachn
No not at all. Reality is reflected by them but not dictated, you jumped to an unwarranted conclusion.
What is your point exactly?


My point was that just because that's what happens most of the time doesn't imply that there is a valid technical reason for doing so.

 

[hatt]

Originally Posted By: kschachn
Originally Posted By: hatt
Originally Posted By: kschachn
No not at all. Reality is reflected by them but not dictated, you jumped to an unwarranted conclusion.
What is your point exactly?


My point was that just because that's what happens most of the time doesn't imply that there is a valid technical reason for doing so.
There is a valid technical reason to drain hot and well mixed. Contaminants held in suspension settle out of oil.

 

[Yup]

I can't remember but it sticks in my mind my owner's manual says warm engine. I'm only about 20% sure. Not sure how much it actually matters. If it's been sitting for months I'd personally want to get any sediment "stuck" in the oil by running it a mile or two at least.

 

[kschachn]

Originally Posted By: hatt
There is a valid technical reason to drain hot and well mixed. Contaminants held in suspension settle out of oil.


That part I don't get. If they have settled out (for which I've never seen proof) then why won't they drain out when you remove the drain plug?

 

[hatt]

Originally Posted By: kschachn
Originally Posted By: hatt
There is a valid technical reason to drain hot and well mixed. Contaminants held in suspension settle out of oil.


That part I don't get. If they have settled out (for which I've never seen proof) then why won't they drain out when you remove the drain plug?
You've never seen proof? The next time you drain well used oil put it in a clear jug. Wait. Report back. I doubt much settles out in a few hours. I know a lot settles out in a few months.

I imagine the largest suspended contaminates do the most damage and are also the quickest to settle.

It may drain out. But who knows. Most oil pans are pretty flat. The threaded area the drain plug screws into is usually raised, trapping a little oil. And finally, cold oil drains a lot slower than 180F oil. Hot and thin oil may indeed flush the area a bit if there were any large chunks of stuff lying around.