interesting conversation about draining oil

[Django]

No thermodynamics talk needed, you just missed the point I'm trying to suggest here: I think you'll get more oil out of your bike by draining it cold, rather than hot. My theory is simply based on where the oil is when it's cold vs hot.

You could drain the oil when it is hot and after letting the motor run. That would give you the advantage of a more fluid oil and all the particles dispersed in the oil.

Then you could let it stay open over night. That would give you the advantage, all oil collects in the sump and get drained, as you assume it is in a cold engine.

[postoak_imp]

Well, one advantage of a cold oil drain that, I think, Mickey mentioned is that you don't burn yourself. So in the absence of other evidence, I would go cold. I'm not convinced that particles in hot oil somehow disperse out of the oil and cling to the motor walls. It sounds good, if you don't think too hard about it, but I doubt it happens.

I'm really interested, because I've always drained it warm. From the first service, I've added 4.1 quarts, and... the oil is always fully above the level of the site glass. So far, no consequences (if I've indeed over filled), but, perhaps I'm adding more and more total oil volume each time I drain (less than 4.1 quarts) and then add back 4.1 quarts of new oil. I think I'll try cold next time, and allow like 30 minutes to drain.
Has anyone experienced a problem of overfilling? Will the oil "foam"?

Why don't you loosen your drain plug until oil is slowly flowing out through the threads until enough oil has come out so that you are at the middle of the sight-glass and from then on just replace the same amount as comes out?

I have two oil jugs. One is for dirty oil and one for clean. I pour the drained oil into the dirty-oil jug to measure it and then put that same amount of oil in the clean-oil jug and pour it into the bike.

[redbirds_imp]

I simply drain mine warm and replace with 4 qts. Fills to the top line every time. It's only important that the oil level is between the low and high marks but for peace of mind it's nice having it right on the high mark.

[mattmcuomo@yahoo.com]

I simply drain mine warm and replace with 4 qts. Fills to the top line every time. It's only important that the oil level is between the low and high marks but for peace of mind it's nice having it right on the high mark.

Same here, never had a problem this way.


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[The A-man]

Why don't you loosen your drain plug until oil is slowly flowing out through the threads until enough oil has come out so that you are at the middle of the sight-glass and from then on just replace the same amount as comes out?

Like some others have mentioned, my thinking has been clouded by two paradigms: 1) always warm the oil before draining, and 2) never trust the siteglass, always precisely measure the amount that you put in (which assumes that all old oil will drain out).

So, thanks to Postoak's suggestion, I think I'll measure how much comes out next time, and fill to the top of the siteglass while being mindful that it should take nearly all of that 4th quart. I'm still a little worried about relying on a measure of how much drains out, just because it seems like there's always some oil that won't drain out of the filter, and there's always some that's left in my drain pan that I have to wipe out with shop rags. Perhaps it's only a few ounces, though. It's good to hear that others do have confidence on the efficacy of the siteglass measure.

[greekcb_imp]

I always like to do my vehicles when the oil is warmed up if possible. Usually with any of my cars i was able to do it hot without risk of getting burned, like being close to an exhaust etc. I did my break in oil on the CB last week and i did it right after riding it. I saw the location of the plug and filter and knew i could do it hot being careful. Now with my enfield and roadliner its a diff story. On the enfield the filter housing is right by the pipe and its not a spin on filter, its an element in a housing with about 8 million parts lol. It has also has 3 plugs for 1.5 quarts! Those are no biggie and 2 of the plugs have screens with very little oil that comes out. I pull them and clean them every time but i know some people leave them for every other change type of thing etc. But im picky so i do it. The roadliner has 3 plugs and 2 of them are in tight spots so i like to do it when its cool because it takes a little to get the plugs on. So in general i like warm but in some cases i have to do it cold. But since i do my oil regularly the oil never gets too dirty. Only thing thats diff is drain time. And id say the most important part is its getting changed!

[Mscb1100_imp]

Hit 600 miles as I pulled into garage after a quick 65 mile jaunt today.
The last 3 miles were from Honda dealers where I purchased oil, filter and new plug gasket
It was a perfect day for riding, I removed windshield and wore my HJC cr3 helmet with ear plugs and had no buffeting and wind noise was minimal with this helmet
Will let the oil drain cold for 3 hours tomorrow AM, refill and get in at least 100 miles tomorrow

[tuareg_imp]

Since I woke up it's been pouring rain. Might be the first day this month I won't get to ride. So my other bike needs it's oil and filter changed, might as well do that today. Was talking to one of my good riding buddies this morning about what he was doing instead of riding today, and he was basically doing the same to his bike on this rainy day.

He says "are you going to warm up the bike before draining the oil?"

I said "I always do, don't you?"

He says "nope, the last time I rode it the oil was warm and when I parked it, all the warm oil drained down into the sump".

I said "yea?" questioningly, like, where are you going with this?

He says "well, if you start it again you are just going to push dirty oil from the sump up into the top of the motor again, where it has to drain back down, so you can drain it from the sump".

I said "That's true, but won't it drain faster from the sump when it's warm?"

He says "Ever open a bottle of oil that's been sitting in your garage for a few weeks?"

I said "yea?" again wondering where he's going with this

He says "did you have any trouble pouring it out of the bottle?"

Hmm now he's got me pondering. Since I was a little kid I was told to heat up oil before draining it, but he's got me thinking now. All the dirty oil did drain down when I last came in from riding and parked the bike I have to assume. Do I really want to push that dirty oil back up into the top of my engine now?

Oil might not get changed until tomorrow. I have to work this out in my head. He may have a point.

What do you think?

I had almost the same conversation with the guys who came to service my sailboat's diesel engine a few years back. I usually do that myself, but since it was in the high 40s(deg. C), typical Mediterranean summer, and I didn't want to bother about getting rid of the used oil, I called the Volvo Penta service. Anyway, 10 minutes after the they arrive they are already pouring fresh oil into the sump. Only then I realized that they hadn't even asked for the ignition key. Wadda heck? Their argument was the same: Do I really want to "contaminate" the uppers and the oil passages with dirty oil? Well they're the authorized service, what do I know? So off they go. First time ever I have seen a cold oil drain. Then I start thinking:
- Why am I draining the oil in the first place?
- to get rid of the dirty oil.
- only dirty oil?
- no, the detergents, viscosity index improvers, extreme pressure agents, anti-wear additives, dispersants, anti-foam agents, corrosion inhibitors and a number or other additives are at the end of their useful lives, either depleted are burned up or whatever. So I need to get rid of the old stuff as much as I can.

There's some basic science here; that dirty stuff had been circulating in those passages until I switched the engine off last time. So it's not going to get any dirtier because I decide to warm up the engine. All that stuff will settle down in the sump after switching off, just as it did the last time. The only difference between warm and cold oil drain is, warm oil drains faster(due to its lower viscosity) and leaves a relatively thinner film on the oil-wetted surfaces. So there will be a smaller amount of dirty oil remaining at the bottom of the sump and in its nooks and crannies(oil from the uppers having already drained back to the sump). The oil filter retains the most of the particulates; the only thing the oil filter does not retain is the heavier particles that have not been picked up through the oil pump intake strainer from the bottom(we usually see those after splitting the engine apart). So a warm oil drain will help a little in this respect too.
Viscosity of a typical multigrade oil(say 10W-40) at 60 deg. C is very roughly ten times less than it was at 10 deg. C(after that it tapers off slowly), so warming up the engine until the oil is in the 50-60-70 deg C region should do the trick, meaning getting rid of as much old oil as possible, with less chance to burn one's fingers.
Having said that, with those modern engines and synthetic/semi synthetic oils, the difference between a warm drain and cold drain could be too small to notice within the useful life of the engine(or of me) so both methods are viable. Then again, a warm drain provides the excuse for the extra trip to the supermarket in the next town which happens to be 100 km away, so I go for the warmer alternative. Just my 2p.

[Mscb1100_imp]

Thought I’d try an experiment while changing my cold oil today.
After draining the oil to where it was just dripping I removed the filter and put it on the oil catch reservoir to drain also, then slid the reservoir to the side.
I placed a clear tumbler with ounce markers under the drain hole and have collected almost 3 ounces of dripping oil in 30 minutes
Will check back at 1 hour mark to see the level then.
For those who have drained the oil and replaced the drain bolt all within 5 minutes and then added 4 qtrs or 4 qts plus 3:2 ounces you may still have 3 to 5 ounces of old oil in the sump. That may be why some sight windows are reporting levels above the full mark.
Will post a picture of small tumbler with final reading later tonight.
After 1.5 hours I had just a tad over 4 ounces of drip oil

[Mscb1100_imp]

I added 4 quarts of oil, started engine and no leaks, shut off engine after 1 minute.
No sign of leaks and oil level is half way between upper and lower line.
Will add remaining 3 .2 ounces or stop if upper level is reached after going for short ride and letting oil drain back down for 30 minutes