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From the obsessive compulsive department:

I've been changing my own oil by driving up on a pair of ramps, draining and filling. Based on a slight overfill condition after adding the specified amount of oil and returning the vehicle to level, I know I'm not getting all the old oil out. This makes sense, since the drain plug is towards the front of the oil pan. Oil must be pooling at the back of the pan due to the angle from the ramps. It can't be more than a couple or three ounces.

I'm not worried about the slight excess. Shaving a couple ounces off the amount added next time will put it spot on. I don't like the idea of leaving a measurable amount of dirty oil if I can avoid it, especially on the one vehicle that only gets out of the garage a few months a year.

I suppose I can try and get another pair of ramps under the rear wheels if they'll fit. Jacking up the rear to level the vehicle would work, too, I guess. Any other ideas? Am am I the only nut that worries about a couple ounces of dirty oil?

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I'm more worried about leaving the heaviest particles of junk sitting in the back of the oil pan, could be metal particles that you might want to learn about. A little extra dirty oil is one (minor?) thing, but heavy pieces of "stuff" is another. [old post, but got new answers today] –  Xen2050 Jan 12 at 13:55

6 Answers 6

up vote 8 down vote accepted

For OCD you can place a flat pan below the oil drain and lower the front wheels to get the remaining oil out, then jack it up again.

Though I would not worry about couple of ounces in your place. Even if your car is level old oil will still remain in the engine (other cavities, thin film, etc.).

For example in my engine that takes 4L of fresh oil, 2 ounces is less than 1.5% of it.

In case you need to flush the old oil completely (e.g. after filling with wrong type of oil) you could use a oil flush mixture (drain old, refill with flusher, idle 5-10 min, drain, fill new oil).

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You'll never get all the oil out anyway - a lot of it is left coating the innards of the engine! I'll second the "don't worry about it" comments. –  Nick C Apr 12 '12 at 10:25
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To take Nicks comment a step further... My drains are on the back of the oil pan (on both cars), so it's the lowest point while jacked up in the front. Books says a wet fill should be 4.5qt. I only put in 4qt and they still both show 0.2-0.3 overfilled when I'm done... You're not going to get all the oil out no matter what you do! :-) –  Brian Knoblauch Apr 12 '12 at 12:04

don't to nothing with your car let it stand on a leveled place then open the bolt and drain it out or you can rise it up a little bit up form the behind and drain it out this will work.

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Back the car up on the ramps so the rear wheels are up, if that allows the plug and filter to be accessible. Be sure to put good (not plastic) hocks on the front and test the integrity before you go under. Remember the weight is in the front and if your not on a completely level pavement it will roll off the ramps and then your bug food. Krona solution btw is the right one, but not really answers the question.

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From personal experience with my cars over 30 years I believe it is ok to drain most of the oil until only slowly dripping. Then replace the drain plug and start the engine for a few seconds (or if paranoid just disconnect the electrics from the distributor and crank the engine via the battery). Then undo the drain plug and allow the dislodged oil to drain.

A surprisingly large extra volume of old oil will be collected.

I did this with my previous turbocharged car over 17 years / 210,000KM every 5 months and when sold it burned zero oil. I also replaced the filter only every-other-change.

I would never have done this before I attended a car meeting where several old bombs had the sump drained and were then driven until they seized. It was amazing how long they lasted.

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I really don't see how anyone could advocate running or even cranking an engine dry? Whether you understand it or not, while performing this, you are causing a great deal of wear which need not occur in the engine. The very small amount of oil which is left when you pull the plug is not going to cause any issues as it gets diluted down by the replacement oil, then filtered by the clean filter ... you especially don't want to do this with a turbocharged engine ... the bearings on the turbo shaft are very picky. –  Paulster2 Jan 2 at 11:53
    
I accept your concern but "the proof is in the pudding". –  Warren Hudson Jan 3 at 20:41
    
I accept your concern but "the proof is in the pudding". In the case of the car with the turbo, I would add that it was tested at 210,000 km and working just fine when the car was sold Also, fuel consumption was constant from brand new and up to the time of sale. My feeling is that the remaining film of oil is sufficient. The last 150,000 km were all using Castrol Magnatec which was not a synthetic. he previous car was also a turbo and bearing tested fine too at 100,000 km. I always allowed the turbo cars to idle down. Both turbos were the originals i.e. never replaced. –  Warren Hudson Jan 3 at 20:59
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It isn't about "feel" or feelings ... it's about what can be proven. Show me anywhere on the internet from a reputable source what you are saying is a good practice and you might have a chance in heck of starting to convince me. Talk is cheap and "the proof is in the puddin'". –  Paulster2 Jan 4 at 0:38
    
"feeling" was a poor choice of word.... theory is all it is. I have provided my experience as some proof and stress that it applied to 2 cars over long term and significant mileage giving some statistical validity, not to mention the several cars driven to destruction. I have no other proof. I would be interested in any proof you can supply. –  Warren Hudson Jan 5 at 3:14

You can get more oil out of the bottom if you take pan off once it's empty. The difficulty of doing this will vary by car, of course. Just be careful if the oil is hot. And you will probably need a new gasket for when you put it back on.

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This is completely unnecessary unless you've got contaminants such as sand in your oil, and then you'd need to tear apart a lot more than just the pan. –  Kevin Vermeer Apr 17 '12 at 9:57
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@Kevin Vermeer I know that. But it does answer the question of getting as much oil out as possible. Note, too, that some service manuals as recent as only 25 years ago still recommended doing this. –  staticsan Apr 17 '12 at 23:39
    
Not an option in my case, unfortunately. Getting the oil pan off requires lifting the engine. –  Mark Johnson Apr 23 '12 at 20:55

Use a pump to remove the oil, and skip the ramps -- unless needed for the filter. I can not imagine it makes any difference-- some oil is left no matter how well you drain. Use better oil or change more often are other answers. The oil gets dirty immediately anyway so I wouldn't want to do anything that could be unsafe like raising all 4 wheels -- just buy a good jack and stands and lower the car to the ground or go with the pump if it bothers you. I'd forget the "problem".

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