Drain "all" oil oil during an oil change or "most"

[trouts2]

Sorry if this has been asked before. I could not find similar threads on searching.

When changing oil how important is it to drain all the old oil?

Generally when mechanics put the car on the lift they take out the plug and do something else for a while as it drains. The car is level and the oil has pretty much stopped dripping or an occasional drip by the time they get back to removing the oil drain can.
Since the oil is warm when flowing out I would think most of the dregs on the oil pan bottom would be flushed out.
There are recesses and pockets in the engine and I guess the only way to get it all would be to turn the engine a few times or tilt the car which would be impracticable.
When I do snowblower single piston engines quite a bit of old oil comes out when the engine is tilted back and forth so I thought it might be the same for a car. Just how much of a difference this makes I'm not sure but I do it anyway.

The other day I got my oil changed. The lift was occupied so they used a floor jack to lift the front end to get at the filter and pan bolt. The car was angled quite a bit and I thought it would leave several ounces of oil oil in the engine and pan so requested they level out the car. They put jack on the other side so the car was side to side leveled but still had an angle front to back. The front was about a foot higher than the back so I asked to drop the front to let all the oil drop.
I thought it was a reasonable request but the shop guy did not but did it anyway. So the question is how important is getting "all" or "most of" the old oil out? Certainly it won't make a difference that would be noticeable quickly say 50,000 to 75,000 miles. How much of a difference would it make over the life of a car in 200,000 miles? My car has 269,000 on it currently and I'd like to see it do 300,000.

 

[GenesisGuy70]

I usually take the drain plug out and then change the filter and anything else, then close it up. That's long enough.

 

[Quest]

No matter how hard you try to drain out all the oil oil, fact is, there's nooks and crannies inside that holds the old oil and cannot be drained unless you disassemble the entire engine.

In reality: with warm oil, just drain it for 5 mins and then plug and re=fill.

Lastly: nobody lose sleep on this subject matter since the dawn of internal combustion engine (a century ago), so you shouldn't have to.

Sleep well.

Q.

 

[edwardh1]

vw used to say for the bugs and square backs in 70s to wait until there was one drop about every 10 seconds, that was long enough.

 

[Chris142]

There's always going to be some left over. The heads are full of dips and valleys and hydraulic lifters are still full etc. Don't worry about a few oz left in.

 

[bigt61]

You've already got 269k, a few drops of dirty oil won't keep it from getting to 300k. People go 300k miles plus using Jiffy Lube and they barely let the oil stop draining before hitting the drain plug with an air ratchet.

 

[ARCOgraphite]

~1/2 qt staying behind is normal. But ramps for oil changes and uneven jacking might put you over 1qt stay behind which is not reasonable. I expect to be within a 1/4 qt of the OM drain refill qty - dry fill qty (from shop manual PDF) you never see unless you are an engine (re)builder.

 

[ARCOgraphite]

This may only be really important if you run vegetable ester oils in a race engine and do a group changeover

 

[spavel6]

I wouldn't worry about it, as others have pointed out.

By the way, I thought I was difficult when I go in for service.. I bet you made the weekly PIA list at the mechanic's

 

[BigCahuna]

I'll bet the oil has been changed by pulling the plug, draining, and re-installing plug for the last 269k miles. So what is getting an extra 1/2 qt out gonna do for it now?.,,

 

[Pop_Rivit]

Think about an engine. Think about all the valleys in the heads(s) that may hold oil. Think about all the other nooks and crannies that hold a few ounces of oil while the oil is being changed.
Now find something worthwhile to worry about.

 

[ccap41]

Originally Posted By: spavel6
I wouldn't worry about it, as others have pointed out.

By the way, I thought I was difficult when I go in for service.. I bet you made the weekly PIA list at the mechanic's

Exactly what I was thinking..

 

[HTSS_TR]

Some auto manufactures have 2 or 3 oil fills, 1 for oil change only, 1 for oil and filter change and 1 for dry fill(after engine rebuilt). Oil change only is usually 1/3 to 1/2 quarts less than filter change, oil+filter is usually 1/2 quarts less than dry fill for 4 cylinders and more for 6 and 8 cylinders.

It is not possible to extract all used oil in any engine with normal drain, regardless of how you do it(till one way or another) and how long you let it drain.

 

[901Memphis]

Every once in awhile after you let it drip til it almost stops, just pour in a jug of Supertech 5w30 and idle the car for 10 minutes and drain it again!

 

[MrQuackers]

^^^^^ YES. Most members here that frequent the rebate/sale forum have a huge stock of oil. Run a fresh cheapie flush and then replace the filter and oil.

 

[Malo83]

^^^^^ Why!!! Talk about a waste of oil, all the tree huggers and tightwads are gonna yell to high heaven about the environment and wastefullness

 

[MrQuackers]

I have the world's smallest violin for those poor souls.

 

[Dallas69]

You are way too worried about this.
Your engine will never know.
This may be the most anal post ever.

 

[cmhj]

People worry too much about the little things.

 

[ccap41]

Originally Posted By: 901Memphis
Every once in awhile after you let it drip til it almost stops, just pour in a jug of Supertech 5w30 and idle the car for 10 minutes and drain it again!


When yo do this, for a temp filter, do you just find the cheapest filter you can get your hands on?