After you drain, how much is still in your engine?

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.46894587797485911556 quart...now I could be off about .00005635442873599 so don't hold me to this.
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OK, now, let's look at some objective information. Here is a screen capture that I just pulled from the TIS (Toyota Tech Info System website). TIS is awesome (if somewhat expensive). I have a year-long subscription, and it gives me access to ALL maintenance pubs, TSBs and so forth for all Toyota, Lex, and Scion vehicles, back about 20 years. About five years ago, when I was driving a 1MZ-FE V-6 powered Camry (that was the 3.0L V-6), I looked it up, and the DRY FILL number (as distinct from the regular oil and filter change), was 0.8 qts higher. Here are the numbers for my present 2AZ-FXE powered Hybrid Carmy.

Dry-Fill-2AZ-FXE.jpg


As you can see, the 2.4L I-4 traps almost as much old oil as does the 3.0L V-6.
 
On my 2.4L Jeep engine, 4 quarts come out in the first 1-2 minutes of draining. I get another 1/2 quart that will trickle out over the next 20-25 minutes.
How much remains after that, I'm not sure.
 
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Pouring some through the engine would probably just flush a little bit of dirty from the bottom of the pan.

i've done it too.
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Y'all need to remember that there will ALWAYS be a relatively fixed quantity of oil that will NEVER come out of the engine, unless you take it completely apart. You can leave the plug out for as long as you want, and it won't make a difference. I usually pour a few ounces of fresh oil into the open filler after the draining oil has reduced to a trickle, but I realize that all I'm doing is essentially washing out the bottom of the pan. The oil that's "upstream" of the oil pump, but has not reached the point where it can drain back to the pan is stuck in there, and WILL be mixed with your fresh oil. This is reflected in the difference between the "oil and filter" amount and the "dry fill" amounts seen in the chart I posted above.
 
Originally Posted By: ekpolk
OK, now, let's look at some objective information. Here is a screen capture that I just pulled from the TIS (Toyota Tech Info System website). TIS is awesome (if somewhat expensive). I have a year-long subscription, and it gives me access to ALL maintenance pubs, TSBs and so forth for all Toyota, Lex, and Scion vehicles, back about 20 years. About five years ago, when I was driving a 1MZ-FE V-6 powered Camry (that was the 3.0L V-6), I looked it up, and the DRY FILL number (as distinct from the regular oil and filter change), was 0.8 qts higher. Here are the numbers for my present 2AZ-FXE powered Hybrid Carmy.

Dry-Fill-2AZ-FXE.jpg


As you can see, the 2.4L I-4 traps almost as much old oil as does the 3.0L V-6.


Much more than I would expect from a 2.4L!
 
After things are slowing to a trickle (and oil filter off), I will often turn the engine over once. Just turn the key on and then off. I think I see more oil coming out after doing this - but not sure how much affect it has. (??)
 
For those that are super worried about the dirty oil that is trapped in your engine at oil change time, you can always do the "Patman flush" Basically what you do is drain the oil as usual, then put the drain plug back in and put a couple of quarts of fresh oil in there. Idle the engine for a minute and then drain that out. I used to do that when switching from one brand of oil to another that way I didn't have as much of the old oil mixing in with the new oil so that first UOA would be a better reflection of the performance of that oil, although at the same time, it had an opposite effect of making that first UOA look a little bit "better" than it truly would normally, so I no longer bother doing this flush (but if you are the new owner of a used car and question it's oil change history you might want to consider doing it)
 
The majority of oil that is left would seem to be in the passageways - the oil holes in the pump, crank, head and block.
Nothing we can do about draining them!
Add this to oil on surfaces and valleys, etc..

Having rebuilt a number of engines over the years, there is not much extra oil left in the system after a good change.
Because filling initially does not require an appreciable extra amount to get them full.

What's left after a change is of no consequence to me.
 
Originally Posted By: Patman
For those that are super worried about the dirty oil that is trapped in your engine at oil change time, you can always do the "Patman flush" ...


That's similar to the Pig Flush, where I bought a 5qt jug of Castrol dino just to use as a 3 minute flush, then put that flush oil back in it's jug till the next time. So relatively clean oil is filling all those pockets. Finally gave up the Pig Flush though. One too many steps.
 
What happens to the guy that uses the filter for more than one OCI, and doesn't drain the filter for the second use? He could have over 20% or more of dirty oil mixing with the fresh fill. That would bother me more than getting that last pint or half quart of oil out.

JMO
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I was reading a poster on BITOG a year or so ago who did just that - left his filter on for several OCIs (and didn't drain it) - I can't remember if he reported UOAs, but I remember him saying his results over the long haul were fine.
 
Then I guess stressing over a pint to half a quart shouldn't matter that much.
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Originally Posted By: mechtech2
. . .
Having rebuilt a number of engines over the years, there is not much extra oil left in the system after a good change.
Because filling initially does not require an appreciable extra amount to get them full.. . .


See the figures above. My 2.4L I-4 traps almost a full quart of old oil that's not coming out unless you break the whole engine down into its parts.
 
Spin it however you want. Eight tenths of a quart is, well, eight tenths of a quart. You can try to make it "sound" however you want, it is what it is.

And for what little bit it's worth, in my engine, that's over eighteen percent of total oil volume. Gee, that's almost one fifth. Hmmmmm, one quart in five.

It is what it is. And all the more reason not to let one fill get too filthy...
 
Dude, only 1/2 a qt is left in the sump?!? I dropped the oil on the Jeep, and yes it flew out of there for a good couple of minutes and then slowed down, but it was still dripping 6o minutes afterward. I'll bet there was a tad more than 1/2 a qt left in there.

-A
 
There's surely not too much wrong with the old oil. It was being used to lubricate the engine 5 minutes before you drained it!

I bet if someone mixed 10% or so drained oil with the new oil and had a VOA done it would look pretty much the same as the VOA on an uncontaminated oil.
 
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