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M54B25 Engine Coolant Drain plug Removal

2003 - 2009, roadster, coupe, facelift
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portculisz4
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M54B25 Engine Coolant Drain plug Removal

Post by portculisz4 » Wed Jul 21, 2021 10:59 am

I am about to do a coolant flush on my 2.5i E85 and would if possible like to totally drain the engine, I understand to do this you have to remove the engine block drain plug (13mm) on the drivers side of the engine since the block holds about 4-5 ltrs of coolant. I have read a number of articles where persons have avoided doing this stating it is difficult to remove and may cause possible damage to the thread in the engine. Can anyone advise me on their own experiences of doing this ??

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GuidoK
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M54B25 Engine Coolant Drain plug Removal

Post by GuidoK » Wed Jul 21, 2021 11:11 am

I had no problem with this. At least, I would have remembered, but I don't so apparently it was quite uneventful.
But my car was probably on a lift as I have one.
I'm guessing there's an aluminium sealing washer between it but I'm certain I didn't replace that (I never do that. If it starts leaking I do that then, but my experience tells me it's almost never necessairy)

To totally drain the system, you also have to drain the heating element.
Disconnecting the hoses and blow compressed air in the systen (while blocking off the room around your air gun of course) still gets out quite a bit after draining.
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portculisz4
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M54B25 Engine Coolant Drain plug Removal

Post by portculisz4 » Thu Jul 22, 2021 10:43 am

Thanks for the details on your experience. I thought about the possibility of using compressed air myself to force out the extra coolant in the engine block, where did you insert the compressed air line, was it into the expansion tank filler and how much extra fluid did it remove ??

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