N20 External Coolant Leak

sspade · 11-10-2022, 05:59 AM

Had the main underbody shield off yesterday and noticed what appears to be a coolant leak towards the BACK of the engine.

Checked all the main cooling components on the front side, which is bone dry.

Any thoughts on what could be leaking? Im down about an inch of coolant every week or two.

ScottSmith · 11-10-2022, 10:20 AM

Did you check the turbo coolant lines? I can't think of anything coolant related further back than that.

You might be chasing two issues. The coolant "leak" might be a blown head gasket, while the leak might be a small oil leak. I was able to easily see oil leaks using a UV light. The one I bought is no longer available but it was a 3W 365nm light from Alonefire off Amazon; there are a ton of alternatives even from the same brand available now. I didn't need to add anything to my oil to see it; I run LiquiMoly HighTech 5w40 which isn't their UV line but still lights up quite easily. I'm guessing any oil will light up as well.

sspade · 11-11-2022, 06:29 PM

!

sspade · 11-12-2022, 07:53 AM

Looking a little deeper into the nuts and bolts...

ScottSmith · 11-12-2022, 10:02 PM

You can probably replace the O-rings on the turbo side without pulling the turbo, but I don't think you can access the other side very easily (TIS says "Remove Turbocharger." Though I've never tried doing this with the motor in the car before.

Maybe the bolt is just a little lose?

SammyNumberOne · 11-25-2022, 10:16 AM

Had similar issue, my coolant feed line was leaking, changing o rings fixed. You can change O-rings on both coolant hose ends that goes to turbo, can be done without removing the turbo, i would say remove heat shield on the block to have more access to hoses.
Note: you will lose good amount of coolant once they disconnected from turbo.

11-10-2022, 05:59 AM	#1
sspade Major General 2465 Rep 5,457 Posts Drives: F30 Join Date: Oct 2017 Location: Stevenson, WA iTrader: (3) Garage List 2016 BMW 320i [7.87] 2014 BMW 328i [6.83]	Had the main underbody shield off yesterday and noticed what appears to be a coolant leak towards the BACK of the engine. Checked all the main cooling components on the front side, which is bone dry. Any thoughts on what could be leaking? Im down about an inch of coolant every week or two. Attached Images
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11-10-2022, 10:20 AM	#2
ScottSmith Private First Class 30 Rep 105 Posts Drives: BMW E46 N20 Join Date: Jul 2020 Location: California iTrader: (0)	Did you check the turbo coolant lines? I can't think of anything coolant related further back than that. You might be chasing two issues. The coolant "leak" might be a blown head gasket, while the leak might be a small oil leak. I was able to easily see oil leaks using a UV light. The one I bought is no longer available but it was a 3W 365nm light from Alonefire off Amazon; there are a ton of alternatives even from the same brand available now. I didn't need to add anything to my oil to see it; I run LiquiMoly HighTech 5w40 which isn't their UV line but still lights up quite easily. I'm guessing any oil will light up as well.
	Appreciate 1 sspade2464.50 Quote

11-11-2022, 06:29 PM	#3
sspade Major General 2465 Rep 5,457 Posts Drives: F30 Join Date: Oct 2017 Location: Stevenson, WA iTrader: (3) Garage List 2016 BMW 320i [7.87] 2014 BMW 328i [6.83]	! Attached Images Last edited by sspade; 11-12-2022 at 08:11 AM..
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11-12-2022, 07:53 AM	#4
sspade Major General 2465 Rep 5,457 Posts Drives: F30 Join Date: Oct 2017 Location: Stevenson, WA iTrader: (3) Garage List 2016 BMW 320i [7.87] 2014 BMW 328i [6.83]	Looking a little deeper into the nuts and bolts... Attached Images Last edited by sspade; 11-12-2022 at 08:10 AM..
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11-12-2022, 10:02 PM	#5
ScottSmith Private First Class 30 Rep 105 Posts Drives: BMW E46 N20 Join Date: Jul 2020 Location: California iTrader: (0)	You can probably replace the O-rings on the turbo side without pulling the turbo, but I don't think you can access the other side very easily (TIS says "Remove Turbocharger." Though I've never tried doing this with the motor in the car before. Maybe the bolt is just a little lose?
	Appreciate 1 sspade2464.50 Quote

11-25-2022, 10:16 AM	#6
SammyNumberOne New Member 3 Rep 6 Posts Drives: BMW F30 328IX with forged N26 Join Date: Nov 2022 Location: USA FL iTrader: (0)	Had similar issue, my coolant feed line was leaking, changing o rings fixed. You can change O-rings on both coolant hose ends that goes to turbo, can be done without removing the turbo, i would say remove heat shield on the block to have more access to hoses. Note: you will lose good amount of coolant once they disconnected from turbo.
	Appreciate 1 sspade2464.50 Quote