Effect of "leftover" oil after drain

[TallPaul]

I ran a UOA at 40 miles on a fresh fill with filter change. Here are the wear metals in that fresh fill:

Iron 8
Aluminum 8
Lead 11
Copper 9

(The previous oil had 12 iron, 3 aluminum, 33 lead, and 6 copper, but still, diluted with all that new oil it should not have shown much, but for the lead.)

Also, these numbers were not generated in 40 miles, because the 5000 mile UOA was not much worse. So this must be leftover oil and/or rinse off from deposits. And I don't think the truck would have more than half a quart remaining in the engine, but who really knows. It takes 6 quarts and I usually get most of that out and always put 6 in, but maybe a new engine gets 7 quarts and the 6 quart refill capacity is accounting for what is left in the engine.

 

[Jim Allen]

This has got to be in the top ten of the pedantic threads of 2006. With a few exceptions perhaps, does anyone seriously think a few cups of oil is going to make a noticable difference in the life of an engine?

 

[TallPaul]

Left over oil should not be a problem in that if half a quart remains on a 5 quart system, it means your fresh fill is really about 10 percent into it's oci, that is it will be about as dirty as if you really emptied all the oil and then drove 500 miles of your 5000 mile OCI. Most of the time your oil is dirtier anyway, so I don't see a problem in that respect, but it does seem to have an effect on the UOA, though in a clean engine that should be insignificant.

 

[Chris Meutsch]

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This has got to be in the top ten of the pedantic threads of 2006. With a few exceptions perhaps, does anyone seriously think a few cups of oil is going to make a noticable difference in the life of an engine?

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Obviously it doesn't with all the long-lived engines spoken about on this website.
However, remember which website you're on.

 

[Iain]

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This has got to be in the top ten of the pedantic threads of 2006. With a few exceptions perhaps, does anyone seriously think a few cups of oil is going to make a noticable difference in the life of an engine?

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Obviously it doesn't with all the long-lived engines spoken about on this website.
However, remember which website you're on.

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[Gary Allan]

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Gary motor oils are designed to be compatible .Some even have moly and boron together!! Not a blanket statement.

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Just because they're not "antagonistic" doesn't mean that mixing yields the same benefit. Again, if there was no difference in additive packages, each and every oil of the same weight would yield identical (or nearly) identical results. Some do tend to have like results ...others do not. I the case of two 10.0 CST oils ..that yield unlike results ...assuming that test conditions are comparable....what would you attribute it to?

For those who have basic "noise" for UOA results, my feeling is that you're looking at the varied amount that gets kicked off of resident surfaces in the bonding of the AW agents ..and the disruption/depletion of AW agents ..and perhaps previously entrained particles in previously established film formations.

Again, we may be looking at the difference in magnitude of comparing something like a value of .001 vs .0005 (in the big picture) and calling it a 50% reduction in 'whatever' ..but it's there in some instances. Too often to be attributed to random chaos.

 

[427Z06]

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...I don't see a problem in that respect, but it does seem to have an effect on the UOA...

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But it sure makes a good case for trending UOAs. And why at least two (preferably three) UOAs should be used when evaluating different oils, unless of course you get some horrendous unaccounted for spike in a wear metal, at which point a professional like Terry should be called in anyways.

 

[Auto-Union]

Good info TallPaul. I should repeat specificly that my interest is about if the TYPE of old oil is sufficient in the leftover quantities expressed to be less-than-ideal in terms of lube performance verses using the same kind of oil every time.

 

[Gene K]

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I don't think there is anything to worry about. at lube centers, they do an oil change in less than 30 minutes or its free! how much do you think they get out?

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They get a bonus based on letting less drain. The really good guys get the plug back in (with luck without cross-threading) loosing less than a pint. Replacement oil isnt free you know!

 

[tenderloin]

That is why I do a "cold" drain after my vehicles sit overnight. As much oil as possible is drained into the pan...and as much as possible drains from the pan.

Now all you hot drain guys can say what you want...but
"hot" drains do not make as much sense as "cold" drains.

When I turn off my vehicle the oil IS HOT. Whatever is to be suspended in the oil IS ALREADY SUSPENDED and headed to the pan. Why the need to take a cold engine with the vast majority of the oil sitting in the pan and re circulate it just to heat it and re suspend particles that were already suspended and now have fully drained into the pan? Again, it makes absolutely no sense to me.

Also unless you are running dino at 30,000 mi OCI's, and it is thick as tar, at virtually any temperature, "cold" oil flows freely and out of the pan...and with it the impurities

 

[tenderloin]

Post deleted by tenderloin

 

[TallPaul]

In many cases a cold change results in much less leakage upon filter removal, at least for my wife's Aerostar 3.0 V6 it works that way.

 

[Gene K]

Paul if that is a 4.6L Ford FSM says Dry Capacity is 6.675 QT. On the 4.6L trucks adding 6.0 Qt after draining placed oil at the mid-point between maximum and minimum. If you filled them to maximum they would hold 6.5 Qt. My best guess is they do indeed retain around 2/3 Qt.

 

[427Z06]

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Now all you hot drain guys can say what you want...but
"hot" drains do not make as much sense as "cold" drains.

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Well, if you going to use ramps, you have to run the engine, unless you park on ramps the night or several hours before. And if you have to run the engine, it's best to get it hot so that more drains down quicker. Further, if you're going to take a sample when draining, you want the oil well blended and to avoid the initial fuel dilution spike from a cold start.

 

[tenderloin]

Starting the engine to get hot? Again, it was hot when it was shut down. Why start the process over again?

Many vehicles (trucks and SUV's for examples) can have oil changes without ramps. If one needs ramps, then so be it, You park it over night or for a few hours. I park mine inside my garage so my neighbors don't have to look at a "shade tree mechanic" LOL

Your point of sampling is valid, but in reality how many times is sampling used compared to just plain old oil changes. Miniscule amount IMO.



The point I am trying to make in relation to the subject of this post..is to get the most out of draining your oil, a "cold" drain IMO is the most effective way to go.

 

[427Z06]

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Starting the engine to get hot? Again, it was hot when it was shut down. Why start the process over again?

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What part of my post don't you understand?

 

[tenderloin]

Hopefully one is either smart enough or has planned ahead of time IF they have to use ramps...to drive up on them after your vehicle is warmed up.

If you were half as smart as you are a smart a s s ...this board would be a better place.

 

[427Z06]

You're the one that said "hot drains do not make as much sense as cold drains" and I simply gave you a couple of reasons when they might make more sense.

Sorry those reasons don't work for your plans on how the universe should operate.

And here's another reason. Ever see someone strip the threads out of an cold aluminum oil pan with a steel plug because previously they had it changed hot at a lube place and they torque the plug on too tight?

 

[D Bone]

You could always do a "half & half" drain........At night, drain the oil and remove the filter when hot, and then let it sit over night and finish up in the morning.

That way both camps are happy and they can stop the

 

[427Z06]

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You could always do a "half & half" drain........At night, drain the oil and remove the filter when hot, and then let it sit over night and finish up in the morning.

That way both camps are happy and they can stop the

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Great idea. Pick whatever method floats your boat.