weird noise coming from 335i engine after shut off

fabzz · 06-30-2011, 12:52 AM

Don't think i've heard it or noticed it before, but today after turning off my car i heard a humming/mechanical noise coming from the engine (near plastic BMW cover) it went away after like a minute or two. is this just like the water pump or something staying on a little after? it sounds almost like a fan or like an extremely quite air compressor or something. i have a sound clip but i don't think i can upload straight to the forum

Bimmer84 · 06-30-2011, 04:02 AM

I forget what it is, but something continues to cool down for a few minutes.. maybe the oil cooler... I read about it a long time ago. The manual might mention it, I'd check there also.

Trojan4evr · 06-30-2011, 09:10 AM

it's your turbos getting cool down.normal.

dyezak · 06-30-2011, 10:08 AM

More specifically to the above post, it's your electric water pump continuing to circulate water through the turbos after shutdown to prevent oil coke'ing from occuring. Oil coke'ing is when your oil is cooked at super high temperatures (like those found in a hot turbo) and it turns into a coal like substance. This would clog the turbo oil gallies and cause them to fail in short order. This is what oil coke looks like:

Yup, it's a solid, doesn't look much like oil huh?

mike-y · 06-30-2011, 11:01 AM

^^That's why it's always a good idea to try and drive easy for the last couple of miles before you get to your destination.. think of it as "cool down laps" for your turbos and oil.

Trojan4evr · 06-30-2011, 03:18 PM

Quote:

Originally Posted by mike-y

^^That's why it's always a good idea to try and drive easy for the last couple of miles before you get to your destination.. think of it as "cool down laps" for your turbos and oil.

+1

06-30-2011, 12:52 AM	#1
fabzz New Member 1 Rep 9 Posts Drives: 335i Join Date: May 2011 Location: CA iTrader: (0)	weird noise coming from 335i engine after shut off Don't think i've heard it or noticed it before, but today after turning off my car i heard a humming/mechanical noise coming from the engine (near plastic BMW cover) it went away after like a minute or two. is this just like the water pump or something staying on a little after? it sounds almost like a fan or like an extremely quite air compressor or something. i have a sound clip but i don't think i can upload straight to the forum
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06-30-2011, 04:02 AM	#2
Bimmer84 Guardian of the Night 109 Rep 1,831 Posts Drives: 2010 335i M Sport Coupe Join Date: Oct 2010 Location: San Antonio iTrader: (5) Garage List 2010 335i E92 [7.50]	I forget what it is, but something continues to cool down for a few minutes.. maybe the oil cooler... I read about it a long time ago. The manual might mention it, I'd check there also. __________________ 2010 335i M Sport Coupe -- Black Sapphire Metallic\|Coral Red\|Loaded\|JB4 Stage 3\|BMS DCI\|VRSF DPs\|Camaross 6k AE\|Performance Gloss Black Grilles\|CF Performance Spoiler\|CF Quad Diffuser\|Double Layer Black Chrome Quad Tips\|CF Roundels\|Smoked Reflectors\|Red Cyba Scoops\|193s Painted Lamborghini Metallic Dark Gray
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06-30-2011, 09:10 AM	#3
Trojan4evr Lieutenant Colonel 494 Rep 1,922 Posts Drives: 2021 G80 M3 Join Date: Oct 2009 Location: Socal iTrader: (0) Garage List 2011 BMW/ E82 135i [1.00] 2007 BMW/ E90 335i [5.50]	it's your turbos getting cool down.normal. __________________ '21 G80 M3 '11 E82 135i DCT (Gone but not forgotten) '08 E90 335i (Gone but not forgotten)
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06-30-2011, 10:08 AM	#4
dyezak General of the Armies 156 Rep 657 Posts Drives: X5M Join Date: May 2011 Location: Plano, TX iTrader: (1)	More specifically to the above post, it's your electric water pump continuing to circulate water through the turbos after shutdown to prevent oil coke'ing from occuring. Oil coke'ing is when your oil is cooked at super high temperatures (like those found in a hot turbo) and it turns into a coal like substance. This would clog the turbo oil gallies and cause them to fail in short order. This is what oil coke looks like: Yup, it's a solid, doesn't look much like oil huh?
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06-30-2011, 11:01 AM	#5
mike-y just another bmw douche bag 195 Rep 3,640 Posts Drives: 1.9L of fury Join Date: Nov 2008 Location: Los Angeles, CA iTrader: (4)	^^That's why it's always a good idea to try and drive easy for the last couple of miles before you get to your destination.. think of it as "cool down laps" for your turbos and oil.
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