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How long to let oil drain out?

Old 08-25-2010, 05:39 PM
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Alfaguy2
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Question How long to let oil drain out?

Just changing my oil/filter in the 911 in advance of a long trip in it on Friday. I notice that this engine keeps dribbling oil for hours unlike most of my other cars.
The oil was well warmed up before draining but even still it keeps on coming. Have to leave it dribble away overnight now as it got too dark to complete the job.

Just wondering how long you DIY mechanics leave the oil drain for?
Old 08-25-2010, 05:57 PM
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ADias
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I do not think that a little oil remnant matters.
Old 08-25-2010, 05:58 PM
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Dave R.
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15-20 minutes
Old 08-25-2010, 06:57 PM
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Mike in CA
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If you're talking about a 997.2 make sure you loosen the top mounted oil filter before reinstalling the drain plug, otherwise a fair quantity of dirty oil will remain trapped in the engine. Not doing so could account for the "dribbling oil for hours" that you mention. Once you've loosened the filter, 15 minutes or so to drain would be plenty.
Old 08-25-2010, 07:16 PM
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rijowysock
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they let mine drip for about an hour. (they were doing other things as well, and just left it while they messed around) it was still dripping steadily after the hour.. but he said it didnt matter.
Old 08-25-2010, 07:57 PM
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f4 plt
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Porsche recommends as some have already said, that you remove the oil filler cap to allow air in. Also slightly loosen the oil filter cover to allow the oil to drain out of that cavity. They also recommend you allow the engine to drain for an hour. If you drain the old oil for less time, when you add oil only add 8 quarts and check the oil level then top off if necessary. The above is for a 997.2 3.8 liter engine.
Old 08-25-2010, 08:07 PM
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VGM911
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Drain time is somewhat shortened if the oil is warm (not hot).
Old 08-25-2010, 08:22 PM
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gray911
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I just changed my oil and let i drain for 2 hours. It still constanly drips. I tilted the car on the left and more oil came out.
Old 08-26-2010, 12:45 AM
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VGM911
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I've also read that once you think most of the oil is out, you should crank the engine for a very short bit to drive remaining oil to the pan/sump from the cylinders, etc.
Old 08-26-2010, 01:12 AM
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acao
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As long as it takes for me to tackle everything else.

I drain the oil first. While that's flowing, I change the engine and cabin filters, clean the throttle butterfly, clean the MAF, reset the service indicator, check hoses and belts, install the new oil filter, wipe down the airbox, and take care of any other projects I had planned (brakes, plugs, etc.). I lower the car (carefully), put the plug back in, and fill the oil. With the annual maintanence check list, it's about an hour.
Old 08-26-2010, 01:39 AM
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mooty
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i run the motor hot.
drain for 20 min.
i need to dump in 9 qts
996gt3 and 97gt3
Old 08-26-2010, 04:53 AM
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Macster
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Originally Posted by Alfaguy2
Just changing my oil/filter in the 911 in advance of a long trip in it on Friday. I notice that this engine keeps dribbling oil for hours unlike most of my other cars.
The oil was well warmed up before draining but even still it keeps on coming. Have to leave it dribble away overnight now as it got too dark to complete the job.

Just wondering how long you DIY mechanics leave the oil drain for?
When engine and oil hot and most of the time it is cause I drive to the office and do the oil change in the shipping area I let the oil drain only as long as the oil stream remains unbroken. Just a few minutes.

I'm under the car with a flash light looking at things and I don't want to expend the effort to get up from under the car then get back down again.

I have everything already laid out so once down and under the car I don't have to get up again if I don't want to.

If you let the oil drain another hour I doubt you'd get more than another teacup's worth of oil from the engine.

There's probably another 2 quarts of oil maybe a bit more in the engine that'll never drain out so another cup or so isn't worth the extra drain time, unless you've got the time to watch to oil drip drip drip drip out of the engine.

I don't.

Sincerely,

Macster.
Old 08-26-2010, 12:24 PM
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Quadcammer
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That 5oz or less of oil that comes out is completely inconsequential.

Drain the bulk, let it drip for a few minutes, and seal it up.
Old 08-26-2010, 01:32 PM
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cbzzoom
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Originally Posted by VGM911
I've also read that once you think most of the oil is out, you should crank the engine for a very short bit to drive remaining oil to the pan/sump from the cylinders, etc.
I sure hope you didn't trick anyone into doing this!
Old 08-26-2010, 02:01 PM
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Edgy01
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Don't even suggest to people that they consider cranking an engine that you have drained of oil. (Someone may take you seriously). I'm sorry, but this entire topic is ridiculous, if I many be so blunt. Open up the drain(s) holes, drain the oil, and within 5-10 minutes max just close things up and refill it. You get absolutely nothing by wasting your time letting it go any longer.
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