Draining the coolant on a 316 E36 BMW.

[Vince70]

When I get back home this weekend Ive got to change the Coolant on my dads 4 pot BMW and flush the system through with a hose and put some fresh BMW blue coolant in the system.

 

I know there's obviously some drain plug buried on the block or radiator somewhere but I was just going to disconnect the bottom hose and put a water hose in the top of the radiator to flush the system then reconnect and put the heater on hot and fill the car back up with fresh coolant.

 

I just wondered Is there any reason why I should follow the correct procedure or will just draining the system from the bottom hose be sufficient.

 

I just know if I do it the correct way I'm going to loose a bolt or washer or bang my head underneath the car while crawling around on a frost covered driveway and I'm just to lazy to do that on my day off.

[MrBiscuits]

Pulling the bottom hose is usually the best way. The drain plug is generally so tight or brittle that you run the risk of snapping it off.

 

I think the early ones have a bleed screw on top of the rad too. Bleeding is a pain with the 6 pots, should be less so on the 316. Sometimes helps to lift the front a bit so the radiator is the highest point.

[320touring]

I tend to drain them from the bottom hose tbh-if the undertray is on it'll run all over the shop anyways!

 

 

Number one tip is as follows.

 

Take empty 2l bottle and chop the base off it.

 

Invert and place in coolant fill point(where the cap is on the rad.)

 

Fill it to near top of the bottle - then start it and bleed.

 

Makes getting all the bubbles out much easier.

 

The usual 'all vents open and blower to 4 ' rule also applies