How to drain 2011 e90 coolant? No radiator drain plug

[E90 eats wallet]

Hey guys, I own a 2011 335i e90. I bought the car like 3 months ago and discovered that the previous owner used green coolant. I am not much of a mechanic but do do some easy hands on fixing. I decided to drain the coolant myself but when I got under the car and took the pan thing off, I looked all over the radiator for a drain plug and there was NOTHING.... I've seen some forums where people unscrew the drain plug but mine does not have one... could someone please help me with finding the plug to the radiator or how to drain? Thanks!!

[RocketSurgeon]

The radiator drain plug sits above the intercooler. You need to remove the intercooler, then you will have access to the drain plug. It only takes 10 minutes to get to it. You may want to flush the system with a little distilled water to get the green out. Be sure to dilute your BMW coolant to 50:50 with distilled water only. Tap water minerals can be problematic.

[pbonsalb]

The Behr replacement service radiator for my 08 E61 535xi does not have a drain plug. The original radiator did.

Many BMW have block drains. You just have to find them. My E90M3 has two, hidden above the header collectors. My straight 6 E36M3 has one, on the passenger side of the block behind the headers. On a stock exhaust car it is hard to get to because one of the headers and 02 is in the way. Maybe a flex head ratcheting wrench or a stubby wrench with another wrench hooked on the open end for leverage.

For a partial coolant change, just pull the lower radiator hose. You don't get all the coolant out of the engine by draining the radiator since some is still in the block.

Zerex G05 is an aftermarket coolant that is pretty close to BMW spec.