Extended drain times???

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Sep 17, 2003
Knoxville, TN
I notice that a lot of you guys do an extended drain time to remove as much old oil as possible. I used to do that too, just as I have always changed the filter everytime I changed the oil.

Point: I had a mechanic tell me not to do it, because I ran a greater risk of oil starvation on startup until the pressure built up, especially in a turbocharged vehicle.

I suspect this particular mechanic might be better off bagging groceries at the local Safeway, and not messing with engines. By doing an extended drain you're removing as much dirty oil as you can, a good thing. When parking your car overnight, most oil drains down through the oil passages into the pan, compliments of gravity. The result is the same, something that never occurred to this mechanic. But to reduce temporary oil starvation after changing your oil and filter, try this:

1. Pre-fill your new oil filter.
2. Do a "hot" oil change, meaning change it right after the engine has been fully warmed up. This will remove more contaminants (just like washing your hands in hot water removes grime better than cold water), will put some of the settled-out particulates back in suspension and drain them out with the oil, and ensure that a thin film of oil is still on moving parts at start-up (unlike "cold" oil changes in which the oil has dissipated).

If you have a turbocharged engine, check your owner's manual and any model-specific maintenance manuals you might have for special oil drain procedures, although I've never actually heard of such an issue. If for 10 seconds after starting the engine post-oil change, you keep your RPMs low, the turbocharger should be spinning at minimum speed anyway, and relatively unstressed.

[ October 15, 2003, 03:03 PM: Message edited by: TC ]
I notice about a 1/2 qt/litre difference in fill requirement when I let the oil "drip-out".
If a fast lube joint does 200 oil changes per day, that adds up to 100 liters of oil that the establishment has to pay for.
Put the drain plug back in ASAP, fill'er up and out the door.
BB Mopars may be an exception.

I definitely agree with not going the way of "Rapid Change". I usually pull the plug firat on a warm engine and drain. Then I check things like air filter, hoses etc and let the filter cool a few minutes, then remove it. I fill the new filter and top off as it soaks in, then put in on, put the plug back in and start filling.

Total drain time 20 min average.
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