Draining out your old crankcase oil

[Durangoboy]

How long do you allow for your oil to drain out of your pan when changing oil.

Myself the least I let it drain is 24 hours. I go longer if I can arrange for the vehicle to be out of service with out any inconvenience but as a rule it is one day.

Just for curiosity I let my truck drain for 2 weeks and after that time period I put a paper towel under the drain hole. The next day sure enuf there were drops of oil on the towel.

The service facilities that spout off 15 minute oil changes do not sound like such a nice way to get the old oil out out and new oil in. I never use them of course and there is no telling how much old oil is still up in the engine. Sure the old oil is diluted by the new oil but why not get all the dirty oil out so long as there is not any problem with the vehicle out of use for a least a overnight.

 

[lawman1909]

Uhh, I may let it drain 20 minutes. By then it isn't even dripping out but a small drop every 10 seconds.

 

[kozanoglu]

15-20 minutes maximum. Do not want any creature to climb up the drain hole.

 

[Klutch9]

Usually only as long as it takes to wash my hands, take out my new oil and set it somewhere convenient if I haven't already done so, and take a few swigs of a colden one. Then the plug goes back in. At that point, the drips are sparse enough to tell me that the motor is pretty well empty of old oil.

 

[crazyoildude]

10 minutes tops i would never let it drain for 24 hours i dont like dry starts dirty oil lubricates much better then no oil maybe that is why on that old oldsmobile custom cruiser we used as a shop car had the original engine with around 400,000 miles give or take

 

[901Memphis]

As long as it takes me to get the old filter off and the new one on. So 10 minutes tops.

 

[Texan4Life]

however long it takes the stream to turn to drips...

 

[gregk24]

As Texan said, I just wait until the stream of oil turns into drops. You are exposing your oil pan to possible contaminants. Something as simple as a breeze blowing could cause dirt/dust to fly up and enter the pan. You are also causing more of a dry start the longer you let the oil drain. No need for that. 10 minutes tops for me.

 

[barkingspider]

I let mine drain until it starts to drip slowly (less than 3 minutes). But I do drive the vehicle to normal operating temps or longer before I drain the oil.

 

[thunderfog]

I also think there is serious diminishing returns on letting oil drain that long. 15 minutes tops. No worries.

 

[OneEyeJack]

When the drips stop I pour in a couple of ounces of oil and watch what comes out. Then it's time to button it up and pour in the new oil.

 

[Chris142]

Long enough to change the filter and hunt up a new plug washer. I maintain my stuff well and am not concerned about a few ounces of old oil left over.

 

[BHopkins]

About as long as it takes for the stream to stop, and change to only a drip here or there. That happens to be the same amount of time, that it takes me to climb back out from under the car from opening the drain valve, and change the oil filter. So, it is not even 5 minutes.

My theory is, if a couple ounces of used motor oil is so poor in quality, that it will severely affect the new motor oil, then there is something terribly wrong. And waiting another 5 minutes, or even 5 days, isn't going to make it any better.

 

[4wheeldog]

I do it with the engine hot. I try to ascertain if raising one end or the other gets more out, and roll the wheels on a 2x4, if that will help.

If I am being totally BITOG anal, when the drip slows to maybe every 5-10 seconds, I pour a couple of ounces of fresh in, and let it slow to the same rate again. But all oil changes are complete within an hour of starting the work. Some of my vehicles, I wait 30 minutes or so, to avoid burning the snot out of myself on the exhaust next to the filter.

 

[bubbatime]

You are draining the oil out of your oil galleys, oil pump, oil pickup tube, etc and are setting yourself up for terrible dry starts. This is way worse for your engine than getting out the last 1 to 2 ounces of oil by letting it drain for an excessive amount of time. Heck, 50% of the time, I don't even drop my oil filter and change it, so all that "dirty" oil stays in the engine. This will NEVER be a problem. Your long drain practice is excessive.

 

[Nick1994]

Maybe 10 minutes tops.

 

[Doog]

On my Honda 1.8L I use an oil extractor and get out 4.1 quarts. If I use the drain plug I get only 3.9 quarts so unless you are getting the last oil out of the recesses in the pan below the oil drain hole........you are leaving DIRTY OIL in your engine.

Think about that tonight...

Muwha ha ha

 

[WiskyBadger]

I leave the plug out until it's a slow drip. Less then ten minutes.

 

[MrQuackers]

I drain for 10+ minutes, then reinstall the drain plug. Then add MMO, let that sit for a spell, then drain. Then reinstall the plug. Add a cup plus of fresh motor oil. Drain that, then reinstall the plug, and fill with the good stuff.

 

[anndel]

10-15 minutes, the time it takes to wipe the oil filter mount, put new oil on the new filter gasket and open the bottles and line them up.