How much residual oil leftover after oil change?

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I got to thinking about this the other day. Is there just a thin film left on all surfaces after the oil is drained (and filter replaced too)? I ask because i plan on doing a UOA after my next change, but i used a little ATF in my oil before the last drain, and im wondering if there is enough of it still in my engine to throw my results off just a bit...?
 
0.7 quarts remain in my Mazda turbo (6.7 quart system). Oil remains in the oil cooler and lines + some in the engine. if you change oil brands you should do the UOA on the second oil change. Seems to be true for most engines as shown in UOAs. A different oil seems to need some running in? before setting down on the second oil change.
 
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Originally Posted By: Eddie
0.7 quarts remain in my Mazda turbo (6.7 quart system). Oil remains in the oil cooler and lines + some in the engine. if you change oil brands you should do the UOA on the second oil change. Seems to be true for most engines as shown in UOAs. A different oil seems to need some running in? before setting down on the second oil change.


ah ok. my problem is i rarely use the same oil twice lol. im pretty satisfied with my current fill, but i think im gonna still mess around with different oils to see which works best with my engine. Im gonna try Rotella 5w-40 synthetic on my next fill, and i think from then on out it'll either be that or Maxlife (what i have now. great for cold starts)
 
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My LS calls for 6.5 quarts. When I change it (the level stays the same for the whole OCI. No make up oil needed) I have to put in exactly 6.5 quarts to get the level on the upper end of the dipstick.

SO The sump more than likely holds 7 quarts and I can only change 6.5.
 
I don't think there is much left unless you don't let it drain very long. I have taken engines apart that the oil was left to drain for a week or so first. Maybe a few ounces remained. If I want a good oil change I leave the drain plug out over night. It has stopped dripping by the time I get back to it.
 
same here, my subaru calls for 4.4l WalMart drained it, and it needed exactly 4.4l to fill to max line. i warm up the engine before an oil change, and if the drain is on one side, i'll drive it up ONE ramp, to tip the car that way. if the drain is on back, i'll drive up TWO ramps, to tip the car back. let it drain for half an hour, and most everything will come out. i didn't open the engine to check, but i find the engine takes what the manual will say, if drained this way.
 
I've gotten probably what seems like a lot (>12oz.) just by lifing the front of the car higher with the jack stand. I'm sure there's more to be found inside the engine...
 
Look in your user manual, in the section where it tells you how much oil you need to do an oil change. There should also be a number for "total capacity" or something. Subtract the oil change number from the total capacity number and that's how much is left in the engine when you drain the sump.
 
Haha I am laughing because my Yaris takes I think 2.9 quarts of oil lol. I am comparing it to soe of these big engines and it seems like so little.
 
my little dodge colt takes 3.5l, i just make sure it's tipped the right way to get out every last drop. it all drains out in 30 min.
 
Originally Posted By: Klutch9
I got to thinking about this the other day. Is there just a thin film left on all surfaces after the oil is drained (and filter replaced too)? I ask because i plan on doing a UOA after my next change, but i used a little ATF in my oil before the last drain, and im wondering if there is enough of it still in my engine to throw my results off just a bit...?


Why the ATF?
 
For Hondas and Acuras w/ K20As, there is 1.1 quarts residual:

k20oil.gif
 
I think it varies from engine to engine. I know my truck has a huge pool of oil on the top of the head. It also has a section of the oil pan that never drains.
 
My wife's 2001 Eclipse with the 2.4 SOHC 4 banger calls for 4.2 quarts, and 90% of the time, that's what it takes to fill it up after a drain. Then again, I do jack the vehicle up and down to get the most oil out I can. Same goes for my grandmother's 2000 Buick Park Avenue with the 3.8. Calls for 5, takes 5, but I do my best to get the most oil out I can.

But, my 86 F-150, I drain it with out a jack. I let it sit overnight, crawl under it, and drain it. It calls for 6 quarts, but gets 'full' after 5 quarts. The oil always looks very clean on the stick after a fresh change, though.
 
In the manual it says that i have a crankcase capacity of 4 quarts (it doesnt mention a different capacity for a filter change) but when i drain it and then add 4 quarts, its right on the full mark on the dipstick. so there must not be that much leftover i guess. i should see how much is required for an overhaul, then i could subtract the crankcase capacity and get the difference
 
Most of this left over oil will be in the heads, so a v- engine will have more left over than a inline one. Also the more stuff in head cams, valves, rockers, etc. the more things to catch the oil. I would say between 1/4 to 1/2 of a quart in each head depending on the design with average of 1/3 of quart. Now that's for a normal drain/fill if you go longer for the drain than 30min. say over the weekend more will come out.
 
Originally Posted By: SevenBizzos
I've gotten probably what seems like a lot (>12oz.) just by lifing the front of the car higher with the jack stand. I'm sure there's more to be found inside the engine...

Not enough to worry about.
 
just enough to make sure your engine doesn't detonate on the first startup.

geez, there are more things to worry about in life...
 
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