Burnt / Corroded Coils N55 MHD Stage 2+

ghost135i · 03-01-2020, 05:35 PM

Anyone experience this before? I installed new plugs and coils about 8k miles ago, and decided to change my plugs today after getting a misfire code last night. Pulled everything out and was shocked to see that coils #1, 3, and 5 are burnt / corroded as shown in the picture.

When I initially changed the coils, the ones that had roughly 60k+ miles on them looked MUCH better than these already do after less than 10k.

Any thoughts?

Gizmo135i · 03-02-2020, 04:26 AM

It’s just rust, there’s water getting into the injector/spark plug wells. Is your engine cover or cowl missing?

ghost135i · 03-02-2020, 07:31 AM

Quote:

Originally Posted by Gizmo135i

It’s just rust, there’s water getting into the injector/spark plug wells. Is your engine cover or cowl missing?

No neither are missing

juld0zer · 03-04-2020, 03:56 AM

I found one recently while replacing plugs on an N20. The spark plug was leaking between the ceramic insulator and the metal. The design of the rubber cap of these coils should prevent any water from getting into the coil bores.

N54Yankee · 03-04-2020, 09:50 AM

Where did you purchase the coils? Did you just replace those three? Odd that 1,3,5 rusted but not those in between.

ghost135i · 03-04-2020, 11:06 AM

Quote:

Originally Posted by juld0zer

I found one recently while replacing plugs on an N20. The spark plug was leaking between the ceramic insulator and the metal. The design of the rubber cap of these coils should prevent any water from getting into the coil bores.

Interesting. Not sure how that would happen unless the plugs were cross threaded though.

ghost135i · 03-04-2020, 11:08 AM

Quote:

Originally Posted by N54Yankee

Where did you purchase the coils? Did you just replace those three? Odd that 1,3,5 rusted but not those in between.

Coils are from FCP Euro. Really not sure what I should do about this. It's just very weird to me that the rubber tips of the coils are burnt, and then the other ones from 2,4,6 are not. Someone previous said water which might explain the rust, but not the burnt rubber tips.

juld0zer · 03-05-2020, 04:16 AM

Quote:

Originally Posted by ghost135i

Interesting. Not sure how that would happen unless the plugs were cross threaded though.

Threads were fine. It appeared to be a defective plug allowing combustion fumes to pass internally between the insulator and the metal exterior

03-01-2020, 05:35 PM	#1
ghost135i Private First Class 52 Rep 130 Posts Drives: 2012 135i DCT Join Date: Oct 2019 Location: New Jersey iTrader: (0)	Burnt / Corroded Coils N55 MHD Stage 2+ Anyone experience this before? I installed new plugs and coils about 8k miles ago, and decided to change my plugs today after getting a misfire code last night. Pulled everything out and was shocked to see that coils #1, 3, and 5 are burnt / corroded as shown in the picture. When I initially changed the coils, the ones that had roughly 60k+ miles on them looked MUCH better than these already do after less than 10k. Any thoughts? Attached Images
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03-02-2020, 04:26 AM	#2
Gizmo135i Second Lieutenant 116 Rep 264 Posts Drives: 135i n55 Join Date: May 2016 Location: Park Ridge NJ iTrader: (0)	It’s just rust, there’s water getting into the injector/spark plug wells. Is your engine cover or cowl missing?
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03-04-2020, 03:56 AM	#4
juld0zer Lieutenant Colonel 480 Rep 1,600 Posts Drives: Prev 135i 7DCT, Now 130i 6sp Join Date: Jul 2016 Location: 2153 iTrader: (0)	I found one recently while replacing plugs on an N20. The spark plug was leaking between the ceramic insulator and the metal. The design of the rubber cap of these coils should prevent any water from getting into the coil bores.
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03-04-2020, 09:50 AM	#5
N54Yankee Lieutenant Colonel 2707 Rep 1,916 Posts Drives: N54 135\|Cobb\|M3 control arms Join Date: Sep 2018 Location: USA iTrader: (0)	Where did you purchase the coils? Did you just replace those three? Odd that 1,3,5 rusted but not those in between. __________________ __________________ "The Constitution was never construed to authorize Congress to infringe the just liberty of the press, or the rights of conscience; or to prevent the people of the United States, who are peaceable citizens, from keeping their own arms.” Samuel Adams
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