ensure all oil is removed during oil change

[paulo57509]

Running the numbers through the oil dilution calculator that someone posted a few years ago, changing the oil three times should get you 100% clean oil (1st change 90%, 2nd change 99%, 3rd change 100%).

This assumes 5qt crankcase and 4.5qt drains.

 

[ltslimjim]

Okay okay okay, hold on.

How about running a low pressure washing machine pumping NEW engine oil through the filler cap while the old is still dripping to 'flush' it out?

Let the car sit for another 2-3 hours?

Though, you may ruin that piece of equipment...

 

[tig1]

The whole point of putting new oil in an engine is for the good of the engine. Starting an engine without oil will ensure bearing damage very quickly.

 

[Speedboat_LS]

Originally Posted By: musicmanbass
Just cuz I'm a little anal I like to dump about 1/8 qt in from the top after the oil has drained, and before I install the drain plug. I know it doesn't get into the engine and probably does next to nothing, but I like to do it and it's my prerogative! My hope is that it flushes out just a few more particles of crud and does a last little washing wave through the drain pan on it's way back out.

Usually when I do this, the first ounce or two still look dark brown/amber, then quickly lightens up to nearly the oil's original color. I only do this when I have a partial bottle of some cheap/free dino wasting shelf space in my garage.


That's exactly what I do. I think many of us have silly little habits when it comes to this sort of thing, and that is one of mine!

I know it probably does next to nothing, but it makes me feel better knowing that I did all I could to get the old oil out of there. Costs less than 50 cents, so why not?

 

[901Memphis]

You only about as much oil as the low line on the dipstick and you could do the double fill with the cheapest 4 quarts of conventional that is right for your engine and drive it for at least a good day before dumping it and starting with your choice of quality oil.

If you have a 4.5 or 5 quart capacity a cheap 1 gallon jug of autozone stuff will take you through a short drive or however long you want to dilute the old oil out before you drain it.

If you really want to get all the old stuff out, grab that gallon jug of oil and a can of seafoam and drive it for a nice warmup trip on the highway before dumping it maybe 50-100 miles.


I can just say +1 to the being crazy wanting to turn the engine over with an empty sump!

 

[Spector]

I actually pour an additional half quart or so of cheap oil in to clean out the oil pan and it does seem to get the little extra in between the oil fill and drain. Of course none of the oil sitting in the zillion other places that cannot drain is still there but I can see the oil change color at the drain as the half quart of oil drains though the engine. I also let my oil drain overnight and that also accumulates another 2-4 ounces or so.

 

[fdcg27]

Don't worry about things you can't change.
Unless you tear the engine down, there will always be some residual oil in it.
People have been draining and refilling engines forever without any issues related to the oil that remains in the engine after it's drained.
This is why I like to run the same oil for several changes, though.
OTOH, there are those who switch up with every change, and their engines last just as long as mine do.

 

[mcrn]

disassemble the engine and clean it! Don't let a few ounces of oil stay in there! Cant have that! no no no...... must go was hands 4 times before touching door knob......................

 

[mcrn]

disassemble the engine and clean it! Don't let a few ounces of oil stay in there! Cant have that! no no no...... must go was hands 4 times before touching door knob......................

 

[Eddie]

My personal experience is that a good plug drain with oil filter will leave ~ 5% old oil in the engine (head, oil galleys, cooler etc) My present engine is a turbo Mazda and the dry fill is 6.8 quarts and the plug drain and refill is 6 quarts or about 12% remains. My other engines vary from 4 to 6%. I see NO reasonable reason to go to any extreme like turning over an engine without oil to get a few extra Oz out. Sometimes I think some of us have lost touch with reality and common sense. Probably would make a good report for an 10o class student in a Psychiatry course. Ha

 

[dblshock]

I fire up the engine for a second, seems to get an additional ounce or two to drop..doesn't seem to bother my Honda's.

 

[gfh77665]

Originally Posted By: Eddie
Sometimes I think some of us have lost touch with reality and common sense.


WORD!

When I think about lack of reality & common sense, the oil hoarders come to mind.

 

[HTSS_TR]

Did anyone try the hair dryer to blow some air into the fill hole for a minute or 2 to see if any more oil coming out from the drain plug ?

 

[Bamaro]

Originally Posted By: Pablo
Originally Posted By: Kuato
Originally Posted By: Pablo
Not unanimous. I am one who thinks getting as much OLD oil out as possible is very important. Turning the engine a couple revolutions without starting it won't hurt the bearings or anything, but with some engines, losing the pump prime is a real concern.



Pablo, I can't believe that you are suggesting turning the engine over without oil in it! Sure, you could do it by hand, but most people will just turn the key and guess what? The engine will start. Kind of irresponsible to suggest something for someone that would likely destroy their engine.



I never ever once suggested he start his engine. Please don't tell me I'm "Kind of irresponsible", when you really didn't read what I wrote!! I merely said a couple revolutions of an engine will not hurt it in the least.

I agree. It may not do much but it surely wont hurt anything. You probably do more damage starting an engine that has been sitting for a few days.

 

[jim302]

It is OK to mix different brands of oil.

There's just no way that there is enough old oil in any noticeable quantity after it has been allowed to drain until it is not dripping anymore.

If you've just fixed a head gasket and are trying to get the coolant/oil milkshake out, then it would be worth running cheap oil/filter that meets your car's needs for a few minutes, then changing it again. If you are just changing oil at a reasonable interval, the small amount leftover can't possibly matter.

Under no circumstance would I attempt to start a car without oil. It would case increased wear, and still wouldn't get all of the oil out.

 

[Kuato]

Originally Posted By: Pablo
Originally Posted By: Kuato
Originally Posted By: Pablo
Not unanimous. I am one who thinks getting as much OLD oil out as possible is very important. Turning the engine a couple revolutions without starting it won't hurt the bearings or anything, but with some engines, losing the pump prime is a real concern.



Pablo, I can't believe that you are suggesting turning the engine over without oil in it! Sure, you could do it by hand, but most people will just turn the key and guess what? The engine will start. Kind of irresponsible to suggest something for someone that would likely destroy their engine.



I never ever once suggested he start his engine. Please don't tell me I'm "Kind of irresponsible", when you really didn't read what I wrote!! I merely said a couple revolutions of an engine will not hurt it in the least.



I agree that you didn't suggest starting, but perhaps I didn't make myslf clear - I meant that 99% of people will bump the starter to turn over the engine, and in many cases that will be enough to start it, with bad results. Just saying.

 

[expat]

I once read about a guy that would pour Kerosene into the engine after draining, and start the engine to wash out all the old, nasty, oil.
I guess he thought it better to have Kerosene dregs in the engine than used motor oil??

People get strange ideas.

IMO a moderate OCI is the safest course.