How to drain oil from cooling system?

How do I drain the oil from the cooling system I blew a head gasket and its full of oil. I have drained it alot of times even with the prestone flush kits and still find oil what do I do?

I've flushed cooling systems with liquid laundry detergent before with good results. I've always mixed the detergent strong then warmed up the engine and drained while still hot. The laundry soap doesn't make alot of suds, that's why I use it. I have done this many times on diesel engines and has always worked great.

This sounds like it should be in the FAQs

THe simplest and best solution is to use Dishwasher soap. THe good old fashion cheap powdered kind. (We used Calgon in the shop) It does not foam up, cleans oil and grease like a hot dam. This was the method that was given to us by a Large BRand Name Equipment Manufacturer, as the the way to clean contaminated cooling systems after oil cooler failures, head gaskets, etc.
Slowly add about 1/2 to 1 cup to a running engine, up to running temp, into the rad and allow it to run for at least 10 minutes ( sound like an aoutmatic dishwasher cycle!)and drain and flush. If you allow it to stay in the cooling system longer it will not hurt anything, and will do a better job. If it still looks a bit murky, do it one more time.
Don't have to add the clear rinse addative, unless of course your looking for a spotless shine on the inside!!!
Martin