Corroded Plugs & Coils

bendeyo · 03-01-2022, 10:19 AM

Over the past month I've noticed some strange acceleration and what seemed to be a misfire but no codes. The car also seemed to be running rich under heavy load with the occasional plume of black smoke when I step on it. I decided to swap the plugs and coils last night and this was the result(attached image). Cylinders 5 and 6(farthest back) were heavily corroded both on the coil and on the plug. I just replaced both the plugs and coils about 20k miles ago and didn't notice anything like this at the time.

Would this just be caused by moisture getting into these or should I be more concerned of something more serious? The plug cylinder(tube the coil is inserted into) did seem a little damp in cylinder 6 but not in 5. Is there anywhere I should check to avoid additional moisture getting in there?

It seems to be running much better today but I'm nervous that I should check them sooner to make sure this doesn't happen again. I did try to wipe up any extra moisture in the plug cylinder.

2013 F30 N55 335xdrive
125,000 miles
Stage 2 Bootmod3 tune 93 octane
Catless DP
Upgraded charge pipe

thejeremyman9 · 03-01-2022, 11:47 AM

Are you running with your engine cover and the OEM foam?

LA1Z24 · 03-01-2022, 11:47 AM

Water is most likely dripping onto the top of the valve cover near those coils, from the hood/cowl area. Although there is a lip around the plug hole to keep water out. And the seal on top of the coil wraps over the lip. Is it possible the coils were not fully seated in the head?

bendeyo · 03-01-2022, 01:44 PM

Quote:

Originally Posted by thejeremyman9

Are you running with your engine cover and the OEM foam?

I'm using the engine cover but not the foam anymore

bendeyo · 03-01-2022, 01:46 PM

Quote:

Originally Posted by LA1Z24

Water is most likely dripping onto the top of the valve cover near those coils, from the hood/cowl area. Although there is a lip around the plug hole to keep water out. And the seal on top of the coil wraps over the lip. Is it possible the coils were not fully seated in the head?

I'm pretty sure they were seated correctly as I've done plugs and coils multiple times on the car. I'm wondering if the rubber seal that goes on the strut bars was not on correctly the last time I did them.

n55david · 03-01-2022, 04:40 PM

Quote:

Originally Posted by bendeyo

Quote:

Originally Posted by LA1Z24

Water is most likely dripping onto the top of the valve cover near those coils, from the hood/cowl area. Although there is a lip around the plug hole to keep water out. And the seal on top of the coil wraps over the lip. Is it possible the coils were not fully seated in the head?

I'm pretty sure they were seated correctly as I've done plugs and coils multiple times on the car. I'm wondering if the rubber seal that goes on the strut bars was not on correctly the last time I did them.

The coil seal was absolutely not sealing.. 100% that

thejeremyman9 · 03-01-2022, 05:57 PM

Its probably a combination of all 3: water gets into engine bay as cowl is not sealed --> engine cover/foam doesnt stop water --> coil is not sealed

03-01-2022, 10:19 AM	#1
bendeyo Enlisted Member 5 Rep 31 Posts Drives: 2013 BMW F30 N55 335XI Join Date: Jul 2020 Location: New Hampshire iTrader: (0)	Corroded Plugs & Coils Over the past month I've noticed some strange acceleration and what seemed to be a misfire but no codes. The car also seemed to be running rich under heavy load with the occasional plume of black smoke when I step on it. I decided to swap the plugs and coils last night and this was the result(attached image). Cylinders 5 and 6(farthest back) were heavily corroded both on the coil and on the plug. I just replaced both the plugs and coils about 20k miles ago and didn't notice anything like this at the time. Would this just be caused by moisture getting into these or should I be more concerned of something more serious? The plug cylinder(tube the coil is inserted into) did seem a little damp in cylinder 6 but not in 5. Is there anywhere I should check to avoid additional moisture getting in there? It seems to be running much better today but I'm nervous that I should check them sooner to make sure this doesn't happen again. I did try to wipe up any extra moisture in the plug cylinder. 2013 F30 N55 335xdrive 125,000 miles Stage 2 Bootmod3 tune 93 octane Catless DP Upgraded charge pipe Attached Images
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03-01-2022, 11:47 AM	#2
thejeremyman9 Major General 4364 Rep 7,606 Posts Drives: 2015 BMW 335i Join Date: May 2019 Location: Cali iTrader: (0)	Are you running with your engine cover and the OEM foam?
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03-01-2022, 11:47 AM	#3
LA1Z24 Captain 358 Rep 770 Posts Drives: 2014 435i M Sport Join Date: Oct 2020 Location: Long Island iTrader: (0)	Water is most likely dripping onto the top of the valve cover near those coils, from the hood/cowl area. Although there is a lip around the plug hole to keep water out. And the seal on top of the coil wraps over the lip. Is it possible the coils were not fully seated in the head?
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03-01-2022, 05:57 PM	#7
thejeremyman9 Major General 4364 Rep 7,606 Posts Drives: 2015 BMW 335i Join Date: May 2019 Location: Cali iTrader: (0)	Its probably a combination of all 3: water gets into engine bay as cowl is not sealed --> engine cover/foam doesnt stop water --> coil is not sealed
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