Arrrgh it's Bitog. Is it pepper or fly excrement?
So the missing information in this "testing" is what defined the end of the drain period? Were all cases drained for the same amount of time? Was the drain period over when the oil only dripped X times in Y time? Without knowing that parameter, it's not a very good test comparison.Does draining the oil when it is hot get the most oil out of the engine?
Three different drain scenarios were compared. The first scenario was
the hot oil drain. The engine was warmed up to a water temperature of
200°F. The engine was running just seconds before draining. The oil
temperature was checked while draining the hot oil and was
approximately l50°F.
The second scenario was the warm oil drain. The engine was warmed up
to a water temperature a l45°F. The oil temperature was checked while
draining the warm oil and was approximately 90°F.
The third and final scenario was the cold oil drain. The engine was
warmed up to 200°F and then allowed to sit for 12 hours in a 50°F
garage.
The results showed that the cold engine drained out more oil than the
hot or warm engine did. The cold engine left behind 0.3% of the engine
oil, while the hot engine left behind 4.5% of the engine oil. The warm
engine left behind the most oil at 6.8%.
Why did the cold engine drain more oil? In two of the three
conditions, the engine was running and oil was being circulated
throughout the engine just prior to the oil being drained out. While
oil flows better when hot, it still takes time for all the oil to
return to the sump, where it can be drained out.
The warm engine oil increased the effect of the oil circulated
throughout the engine. Warm oil does not drain back as quickly to the
oil sump as hot oil does, so more of the oil is left in the engine in
the few minutes it takes to drain the oil sump.
Does draining the oil when it is hot get the most oil out of the engine?
Three different drain scenarios were compared. The first scenario was
the hot oil drain. The engine was warmed up to a water temperature of
200°F. The engine was running just seconds before draining. The oil
temperature was checked while draining the hot oil and was
approximately l50°F.
The second scenario was the warm oil drain. The engine was warmed up
to a water temperature a l45°F. The oil temperature was checked while
draining the warm oil and was approximately 90°F.
The third and final scenario was the cold oil drain. The engine was
warmed up to 200°F and then allowed to sit for 12 hours in a 50°F
garage.
The results showed that the cold engine drained out more oil than the
hot or warm engine did. The cold engine left behind 0.3% of the engine
oil, while the hot engine left behind 4.5% of the engine oil. The warm
engine left behind the most oil at 6.8%.
Why did the cold engine drain more oil? In two of the three
conditions, the engine was running and oil was being circulated
throughout the engine just prior to the oil being drained out. While
oil flows better when hot, it still takes time for all the oil to
return to the sump, where it can be drained out.
The warm engine oil increased the effect of the oil circulated
throughout the engine. Warm oil does not drain back as quickly to the
oil sump as hot oil does, so more of the oil is left in the engine in
the few minutes it takes to drain the oil sump.
In the case of the cold oil drain, the engine was hot when turned off.
The 12 hours of sitting allowed (almost) all the distributed oil to
return to the oil pan.
What About Particulates? SAE standards and research papers show that
oil filters capture particles down to 10 microns. When the engine is
turned off, the oil is relatively free of particles larger than 10
microns, and particles smaller than 10 microns will stay in suspension
even when the oil is cold.
What About Water and Fuel Contamination? In most cases, oil
contamination is held in suspension. Waiting until the oil is cold
will maximize the amount of contaminants that actually drain out.
Running the engine before changing the oil spreads the contaminated
oil throughout the engine, increasing the amount of contaminated oil
that is left behind and mixes with the new. clean oil.
What Was Drain Time? It took about twice as long to drain the cold oil
from the sump compared to the hot oil. The warm engine oil split the
difference in time between the two. But in all cases, draining the
sump took less than four minutes.
What's The Verdict? It's fine to drain used oil from a cold engine.
This avoids dealing with scalding hot oil and working around a hot
exhaust system. As a bonus, it also drains more of the dirty oil from
the engine.
So how many drips do you draw the line?So the missing information in this "testing" is what defined the end of the drain period? Were all cases drained for the same amount of time? Was the drain period over when the oil only dripped X times in Y time? Without knowing that parameter, it's not a very good test comparison.
I typically drain oil within 20 minutes of a hot shutdown (so oil is still pretty hot), remove the filter and then let everything drain over night. So by the next day all oil has stopped dripping. But, if I don't do the over night drain I will typically let it drain for up to an hour while I change the filter and do some other checks. After an hour, the dip rate is pretty low.So how many drips do you draw the line?
Wait ... so in all cases the oil was only allowed to drain for less than 4 minutes? With the oil at room temperature, it's going to take more than 4 minutes to get an effective sump drain. Sure, all the oil that could drain down from the top end of the engine into the sump did so already, but I'd bet there was still some oil dripping pretty good after draining cold oil for less than 4 minutes.What Was Drain Time? It took about twice as long to drain the cold oil
from the sump compared to the hot oil. The warm engine oil split the
difference in time between the two. But in all cases, draining the
sump took less than four minutes.
I lost the source during a HD upgrade...
It is too bad that @BusyLittleShop lost his source for the study that was done on this subject. Without it, or some other data, all we have are theories and opinions.
Having that "new block" specification is referenced often by Hyundai mechanics.Hyundai will give you three oil fill specs. Oil and filter change, oil pan or new block. My Gen Coupe has a sump in the front of the pan that will retain about a pint or so no matter what.
1.6L Accent
Total oil 3.8L
Drain and filter 3.3L
New oil pan 3.0L
2L Gen Coupe
Total oil 5.9L
Drain and filter 5.3L
Oil pan 5.0L
Basically the filter is .3L But at least .5L is trapped in the block/pan.
I tend to think, if there are particles, most of them are in the filter.. or floating around in the oil..Well, if you believe that there are "particals" circulating in the engine, then the thing to do is to warm it up and get them suspended in the oil. So that when you drain the oil, they will be removed because they are in suspension in the oil.
By now, those particles are all in the bottom of the sump, where they will stay when you drain the oil.
So, are there, in fact particles in the engine?
The search function on this and other Xenforo website forums leaves a lot to be desired IMO YMMV
The search function on this and other Xenforo website forums leaves a lot to be desired IMO YMMV
That's for US made engines. Both my Korean engines have been rock solid.Having that "new block" specification is referenced often by Hyundai mechanics.
Per the article, the end of the oil draining period was: "When no more oil was seen running down the clear tube ..."Here's a PDF of the source:
https://www.starbikeforums.com/attachments/hotorcoldoil-pdf.109114/
I am glad you have had a positive experience, but please.That's for US made engines. Both my Korean engines have been rock solid.
Please what? 345k miles between the two.I am glad you have had a positive experience, but please.