Draining your bike's oil - hot or cold?

I just read an article in the September 2019 issue of Road Racing World that discussed whether to change your bike's oil hot, warm or cold.

The testers went to a lot of trouble to measure and control how much oil went in and how much came out, including what was left on the funnel and the bowl the oil was drained into.

The conclusion: Cold - More oil drained out cold. And they determined the amount of contaminants left behind was less than either the hot or warm drain scenario.

The article is titled "Draining Engine Oil: What's Better? Hot or Cold?" by Jason McDonnell.

Interesting as everything I've read in my owner's manuals talks about getting the engine up to operating temperature before doing an oil drain, i.e. hot.

It sure would be easier doing the drain cold, especially on our new K1600GT Sport.

Thoughts?

Take a ride.
Drain the oil when you get home.
Enjoy your evening and a good night's rest.
Finish the oil change in the morning.

Best of warm and cold.

draining the oil

mehrten said:

I just read an article in the September 2019 issue of Road Racing World that discussed whether to change your bike's oil hot, warm or cold.

The testers went to a lot of trouble to measure and control how much oil went in and how much came out, including what was left on the funnel and the bowl the oil was drained into.

The conclusion: Cold - More oil drained out cold. And they determined the amount of contaminants left behind was less than either the hot or warm drain scenario.

The article is titled "Draining Engine Oil: What's Better? Hot or Cold?" by Jason McDonnell.

Interesting as everything I've read in my owner's manuals talks about getting the engine up to operating temperature before doing an oil drain, i.e. hot.

It sure would be easier doing the drain cold, especially on our new K1600GT Sport.

Thoughts?

Click to expand...

My thoughts:
I do not claim to be an expert and really hate to feed into an "Oil thread" but I have probably done a thousand oil changes in 50 years. My theory: You want the oil hotter because it will flow better. Also, if you run the motor first, any junk in the oil will, hopefully, be mixed up and in suspension (instead of sitting in a layer on the bottom) when you let it out. However, it's easier to handle oil that won't burn the s**t out of your hands. My solution: Start the bike and run it for a couple of minutes to warm it up and get all the contaminants/solids, if there are any, moving around with the oil. Then drain it out and change the filter. Then refill. It's not an exact science and if 95% of your contaminants are removed, you're good to go. It is said that the longer you leave the oil in the more it loses its lubricity. However, the factory recommended intervals are very conservative and no harm can come if you change oil and filter +/- 10% mileage of the recommended, no matter how you do it, in IMOH. More oil being drained out cold is counter-intuitive. Contaminants in the oil being the same hot or cold, not so counter intuitive, unless you don't consider take into account that there may be solids which tend to settle. A magnetic drain plug will show you what crud there can be in the oil.

Felaw,

Everything you question was addressed by the article.

They talked about the amount of contaminants in the oil hot or cold.

Per the article the filter does most of the contaminant removal with the rest staying in suspension because of its small size.

They also talked about running the engine for a minute or two, i.e. the warm scenario, it was the worst.

So here's a counter proposal...

Go for a ride. Park the bike. In the morning when the bike is much cooler drain the oil, change the filter, etc.

No hot drain plugs or hot oil over my gloves.

Seems simple yet like you say, doesn't seem right because of all the "training" we've received in the past.

Yet their conclusion was just that...park it for the night and drain it in the morning.

Lots of real world input here: https://tinyurl.com/y439hvy4

Joe

lkraus said:

Take a ride.
Drain the oil when you get home.
Enjoy your evening and a good night's rest.
Finish the oil change in the morning.

Best of warm and cold.

Click to expand...

Yep! I do it this way fairly often. As to cold or hot? I always drain it hot. I often let it sit over night or even a few days if other things delay finishing the oil change.

Once in a while I don't even worry about it and drain the oil hot, swap out the filter and dump fresh oil in right away. After all, the old oil really was not that bad. If the old oil was that bad you should have changed it a long time ago. I don't see the harm in a few ounces of the old oil left in the crankcase. It simply is not that contaminated.

Thanks for the responses...

Has anyone else actually read the article?

I have always drained the oil hot because that was the preached way based on "lots of real world experience."

Now along comes a moto journalist, acting as a scientist or engineer, who's added in some facts that seem to support a different way.

Not sure it even matters given the quality of the oil most of us use, and the oil and filter change interval most of us adhere to.

Makes for an interesting discussion.

mehrten said:

Felaw,

Everything you question was addressed by the article.

They talked about the amount of contaminants in the oil hot or cold.

Per the article the filter does most of the contaminant removal with the rest staying in suspension because of its small size.

They also talked about running the engine for a minute or two, i.e. the warm scenario, it was the worst.

So here's a counter proposal...

Go for a ride. Park the bike. In the morning when the bike is much cooler drain the oil, change the filter, etc.

No hot drain plugs or hot oil over my gloves.

Seems simple yet like you say, doesn't seem right because of all the "training" we've received in the past.

Yet their conclusion was just that...park it for the night and drain it in the morning.

Click to expand...

Well, like I said, I'm no expert and I haven't read the article and probably won't because I would have to subscribe to do so. Therefore, I can't realistically refute their findings or criticize their methodology. But a few facts are beyond argument: Hot oil flows faster than cold. Metal particle contaminants will get trapped in the filter or eventually settle to the bottom. When I was doing oil change for a fleet of trucks we would puncture the cans, drain them into the crankcase and when the oil had stopped draining we put the cans upside down on a rack with a drain can. Every week we would get a good pint or so of oil from the "empty" cans but it took a couple of days for the residual oil to run down into the drain can. No doubt, you will get more oil out of the crankcase, hot or cold, if you let it drain over night but, waiting for the oil to cool down before you drain it makes no sense to me.

I changed bike oil hot once. Burned myself and swore never again, that was 40 years ago. My bikes and cars have all been fine, periodic testing by Blackstone seems to confirm my decision. I've heard the arguments for warm, hot, etc. but like a lot of things correlation, causation, and coincidence are often confused.

Holy crap, I think getting guys to change their oil themselves is a step in the right direction, now there's people telling them when and how hot or cold it has to be to get it done correctly.
Change your oil whatever way you get it done and go ride your bike.
I don't like to burn myself on hot oil so I let it cool down a bit before getting the plugs out.

I usually change oil "warm". If after a ride I wait a bit. If the bike is cold I will start it to stir things up and get into suspension anything that would be suspended. Never hot enough to burn me and never stone cold either.

I've never worked on a K16, but aside from that - hot or at least pretty darn warm.
Shouldn't even be an issue.
Even the cheapest pair of vinyl gloves - like the blue ones from Harbor Freight, or even the clear lightweight "food handling" gloves - will give you a lot of protection for the job.

And that statement about "more drained out cold" ... if that were true, why would the people who design & manufacture liquid lubricants specify viscosity the way they do...?

Maybe, cold oil holds the contaminants more tightly, and gravity pulls them out with the oil. Less viscous warm oil might let them slip out of suspension before they reach the drain hole?

It does seem odd that I've never heard a cold oil change recommended anywhere before this.

It just may be that over the long run it does not make a significant difference.

When I've asked BMW mechanics at dealerships how they get the bikes up to operating temperatures for oil changes during service, they have told me that don't have the time to warm the up the engines. They simply drain them cold.

I have always drained my oils shortly after returning home from a ride with the bikes at operating temperatures. It is not unusual for me to let them drain overnight.

Here's a thought. Take two identical motorcycles and ride them for the same distance to fully warm the oil. Park them. Remove the drain plug from one bike, but let the other fully cool down, then remove its drain plug. Both bikes have had hot oil drain into the sump. The only difference is that the plugs were removed at different times. I have a hard time imagining how there could be much difference. I'd like to see the methodology used in the experiment. Old habits die hard, but I'd enjoy being convinced that cold is better.

I find it hard to believe that less oil drained out when hot, unless they pulled the plug for 10 minutes and stuck it back in.
I always drain hot, I always will, I don't give a rats a$$ what some magazine says. Particulate in the oil will settle out, after a good ride it is all mixed up. Also I generally pull the plug and let it drain for a few hours or over night. I have more than one motorcycle, it might sit a week with the plug out. I don't believe and oil change on a cold engine will get out more oil than a week long drain. I might believe there is no difference between hot and cold, but to say cold is better? Nope, not buying it.