2017 340i weird coolant color in secondary

magbarn · 11-23-2019, 11:49 AM

I was looking at a friend's 2017 340i with about 20000 miles on it and popped the coolant lids to check (as the B58 seems to be prone to lose coolant). Anyways both were just slightly low around the min mark but I noticed the smaller tank's coolant color was a bit off. The larger main tank was blue/green color while the secondary looked like pic below. Should he be worried?

Billfitz · 11-23-2019, 04:03 PM

I'd say it bears looking into. It doesn't even look like coolant.

Orion4 · 11-23-2019, 04:55 PM

What did it smell like? Make me a bit concerned that oil may contaminated that somehow.

magbarn · 11-23-2019, 09:17 PM

Smells like antifreeze. Wouldn't oil make it look milky?

amw896 · 11-26-2019, 07:31 PM

cant believe how many b58s are prone to these coolant and oil loss issues. For the record, there is no way this is normal. Oil and coolant are clearly mixing which will almost surely lead to a grenaded engine in time.

My n55 for comparison had 45k and was 4 years old when I sold it. Coolant tank was light blue in color since day 1.

Rebound · 12-06-2019, 07:34 PM

He should be worried if the car is out of warranty. But if it's in warranty... he should still be worried. If there's oil mixing with the coolant, you want it fixed properly, not just some band-aid. At an absolute minimum, I'd want both the engine and coolant systems thoroughly flushed and I'd expect them to put some extra warranty on the engine. And also do a compression test.

Either way... oil in the cooling system or coolant in the engine... it's very harmful. Odds are, no harm done, but these cars are too expensive to just put a band aid on until it's out of warranty

n00bkiller944 · 12-11-2019, 08:57 AM

Woof, interested to see what the update is. It certainly looks like oil contamination

cfm56d7b · 12-11-2019, 09:12 AM

Is your friend's car still under warranty? If yes - please ask him to visit the dealer as soon as possible. This is definitely not normal.

magbarn · 12-11-2019, 10:13 AM

He came back and said that coolant change in the secondary circuit is normal. Claims there was no oil in the coolant as oil would make it turn "milky"

JimKden · 12-12-2019, 08:20 AM

If it's normal to turn that color, then how come mine is as clear and the same color as the engine coolant? I'd send a sample to an independent lab for checking and stuff the results in the dealer's nose. Buy a bunch of antifreeze test sticks and check it.
That second circuit only cools the air/water cooler, no reason for it to have been overheated and scorched. From my experience specifying steam heated glycol heat exchangers, the film temperature has to be kept below 345F or glycol deteriorates.

11-23-2019, 11:49 AM	#1
magbarn Lieutenant 171 Rep 418 Posts Drives: '17 540i Msport Join Date: May 2009 Location: Southern CA iTrader: (0)	2017 340i weird coolant color in secondary I was looking at a friend's 2017 340i with about 20000 miles on it and popped the coolant lids to check (as the B58 seems to be prone to lose coolant). Anyways both were just slightly low around the min mark but I noticed the smaller tank's coolant color was a bit off. The larger main tank was blue/green color while the secondary looked like pic below. Should he be worried? Attached Images __________________ G30 540i Msport G05 X5 xDrive40i Msport Retired '03 330i, '10 335d
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11-23-2019, 04:03 PM	#2
Billfitz Lieutenant General 8270 Rep 16,125 Posts Drives: '15 328iX GT Join Date: Jan 2015 Location: New Hampshire iTrader: (0)	I'd say it bears looking into. It doesn't even look like coolant.
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11-23-2019, 04:55 PM	#3
Orion4 Lieutenant Colonel 481 Rep 1,572 Posts Drives: 2013 335i Sport Line Sedan Join Date: Aug 2009 Location: Melbourne, FL iTrader: (0)	What did it smell like? Make me a bit concerned that oil may contaminated that somehow.
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11-23-2019, 09:17 PM	#4
magbarn Lieutenant 171 Rep 418 Posts Drives: '17 540i Msport Join Date: May 2009 Location: Southern CA iTrader: (0)	Smells like antifreeze. Wouldn't oil make it look milky? __________________ G30 540i Msport G05 X5 xDrive40i Msport Retired '03 330i, '10 335d
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11-26-2019, 07:31 PM	#5
amw896 Major 583 Rep 1,117 Posts Drives: 2015 BMW M235i Join Date: Feb 2016 Location: ontario iTrader: (0) Garage List 2015 BMW M235i [10.00]	cant believe how many b58s are prone to these coolant and oil loss issues. For the record, there is no way this is normal. Oil and coolant are clearly mixing which will almost surely lead to a grenaded engine in time. My n55 for comparison had 45k and was 4 years old when I sold it. Coolant tank was light blue in color since day 1.
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12-06-2019, 07:34 PM	#6
Rebound Second Lieutenant 153 Rep 258 Posts Drives: F33: The 435i Convertible Join Date: Dec 2017 Location: Oregon iTrader: (0)	He should be worried if the car is out of warranty. But if it's in warranty... he should still be worried. If there's oil mixing with the coolant, you want it fixed properly, not just some band-aid. At an absolute minimum, I'd want both the engine and coolant systems thoroughly flushed and I'd expect them to put some extra warranty on the engine. And also do a compression test. Either way... oil in the cooling system or coolant in the engine... it's very harmful. Odds are, no harm done, but these cars are too expensive to just put a band aid on until it's out of warranty
	Appreciate 0 Quote

12-11-2019, 08:57 AM	#7
n00bkiller944 Lieutenant 126 Rep 424 Posts Drives: '14 328d M Sport Join Date: Mar 2018 Location: Richmond, VA iTrader: (0)	Woof, interested to see what the update is. It certainly looks like oil contamination
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12-11-2019, 09:12 AM	#8
cfm56d7b Lieutenant General 5899 Rep 10,274 Posts Drives: 2017 440i Gran Coupe & 2015 X5 Join Date: Nov 2012 Location: Orange County, CA iTrader: (2)	Is your friend's car still under warranty? If yes - please ask him to visit the dealer as soon as possible. This is definitely not normal.
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12-11-2019, 10:13 AM	#9
magbarn Lieutenant 171 Rep 418 Posts Drives: '17 540i Msport Join Date: May 2009 Location: Southern CA iTrader: (0)	He came back and said that coolant change in the secondary circuit is normal. Claims there was no oil in the coolant as oil would make it turn "milky" __________________ G30 540i Msport G05 X5 xDrive40i Msport Retired '03 330i, '10 335d
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12-12-2019, 08:20 AM	#10
JimKden Private 18 Rep 80 Posts Drives: 2016 340xi Join Date: Jul 2018 Location: Denver iTrader: (0)	If it's normal to turn that color, then how come mine is as clear and the same color as the engine coolant? I'd send a sample to an independent lab for checking and stuff the results in the dealer's nose. Buy a bunch of antifreeze test sticks and check it. That second circuit only cools the air/water cooler, no reason for it to have been overheated and scorched. From my experience specifying steam heated glycol heat exchangers, the film temperature has to be kept below 345F or glycol deteriorates.
	Appreciate 0 Quote