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Discussion Starter · #1 ·
What started as a simple gasket job turned into a complete valve cover replacement. Upon removing the front valve cover, I noticed the two spark plug gasket holes were melted and cracked. I bought 2011 Pilot at 125,000 miles and it has 165,000 now. I’ve performed the plugs and timing belt maintenance, and never noticed any signs of overheating, front end damage, or anything else that could cause a valve cover to become cracked.

Any ideas on what could cause this to happen? My best thesis now is a cracked coil pack that is causing excessive heat.
 

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Happened to me on my high milage Crosstour.
 

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After looking at these examples, the deformation may be due to a combination of variations in metallurgy (hardness), and as some observed, to direct coil pack leakage through cracks, or eddy current heating from the coil pack (very specific spots on the valve cover coil riser). If that is heating the riser, and there was oil or PCV blowby in that area, I could also believe accelerated oxidation of aluminum in those spots.

The cracking seems most often at the base of the coil riser, which may be caused by vibration; the coil boot is fixed to the plug, which is in the HEAD, and the coil and its weight are on the valve cover which is mounted by flexible gasket. i.e. the valve cover and coil moves relative to the plug and head and after thousands of miles, the base metal of the cover coil riser fatigues, cracks and some pieces break off, which exposes fresh aluminum to corrosion.

Also guessing VCM doesn't help here as the engine motion in some modes is fairly violent as compared to 6 cyl operation.

Be curious if 2012 and later valve cover designs were quietly beefed up.
 

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Not aware of aftermarket sources. Take the old one to junk yard and see if a '12 ~ '15 cover would work for fitment and hoses, etc. Or pick a junk cover from your Gen Pilot without visible defects. And disable VCM! (before Grease says that).
 

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I think @AVC has you pretty well covered on the how... I will offer my condolences since it's never fun when a pretty simple project turns into a PITA.
 

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This is sort of what I was thinking. Any suggestions on brand to purchase or stick with OEM?
I am unaware of any aftermarket valve covers for this vehicle. I bought OEM. They come with spark plug tube seals and the front cover comes with a PCV valve as well. Grommets and valve cover gaskets sold separately.
other advice I can give is to lube the spark plug tube seals before attempting to install covers.
 

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I think we will begin to see more 2nd gen Pilots with this issue as the vehicle ages with 200k miles +.
 

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Discussion Starter · #10 ·
Thanks everyone for your replies. Once again, this site has proven and invaluable resource. I got OEM coils from rock auto. That should resolve the issue
 
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