Easy and Fast E46 M3 Coolant Flush

This is a quick and easy coolant flush guide for the E46 M3. Instead of removing the lower radiator hose (which is very troublesome) I removed the temp sensor from the lower hose to open the system. I also went a step further and removed the engine block bolt to drain the coolant from the block. Once that was opened, I added water to the expansion take to flush out any remaining coolant. You want to perform this every 2 years to prevent corrision, blockages or damage to the engine or cooling system.

I used the following DIY's as a guide when I made this video:

Note: THE USE OF THIS DIY IS FOR YOUR REFERENCE ONLY. I DISCLAIM ALL LIABILITY FOR DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR INJURIES THAT RESULT FROM ANY USE OF THE EXAMPLES, INSTRUCTIONS OR OTHER INFORMATION IN THIS DIY.

[marccusumano]

Thanks for the video..why didn't you remove the lower hose like in the DIY you linked in the description?

[ewrtsdhxcvn]

Many thanks for the video and walkthrough. Just completed the coolant refresh for the first time on my own.

The only thing I couldn’t confirm for sure was after filling the system back up how high was your floater measure? Mine was too high and I had to use my bleeder valve to let a bunch of water out.

Either way, massively helpful!

[betitoroks]

what should i do if i can’t squeeze the sensor out?? it seems to be very stuck on my car

[AChannel]

so at the start you turn on the heater ...when did you turn it off? when you are taking out the sensor or when?

[PinguVillage]

Thanks for all the info, super well explained and very clear!!! 👍🏼💪🏼

[Theteese]

Would luv to have seen you getting the bolt out of the block but conveniently missing from Vid....Wonder Why ????

[Armanii]

Man great job I'm so nervous to diy

[sharpwilliams]

I watched three different videos including this one, and none of them said which side of the engine block that the coolant screw was on. I had purchased a reproduction service manual. The answer it gave was "on the same side as the exhaust at the 2nd cylinder." On a 2003 BMW 325 xi, that's the passenger's side. It's hard as h*** to get to.

[Troymatti]

I usually blow some Air after flushing the block with some water ! in this case You'll have nothing left and good to put the new antifreeze

[caliscrizle]

Thanks for that instructional video for changing out the coolant on the e46 m3, also very very nice csl airbox! may I ask where you purchased that?

[DENIS]

Im loving that M i got a Og one but that csl airbox would be lovely are you selling it?

[JeffThompson]

good video, thanks. you need to take more pictures of that intake!

[Theteese]

For something that's called upon every 2 - 3yrs for maintenance, surely BMW could of come up with easier access / easier system to do the coolant flush.... drain plug in the radiator ( which the 325i etc have ) and a drain plug with tap system in the

[BluePurpleRed]

Thank you! I bought it off someone else.