The old water and ignition coil gremlins...
In 20 years I've never had issue with water. I've washed my engine directly, used every kind of car wash (by hand at home - sometimes without warming up engine before or after, commercial DIY station, tunnel, gas station automatic), driven in ridiculous downpours, driven in sustained rain for hours, driven full track day where it never stopped raining, rain at 120MPH on track, etc.
Yet others have seemingly frequent issues with this and I don't want to downplay/minimize their pain/experience (plus, working in IT, I kind of despise the common "but it works for me" response).
Hard to discern what is going on, but from the following quotes I wonder if the seeming consensus of a "poor design" causing this is only
half true. Like if everything is installed correctly, things are fine...but the design allows for parts to be installed incorrectly without any indication of such. And that misinstallation is not only common, but often/usually overlooked during troubleshooting because it is so non-obvious (unless explicitly looked for).
Chris @ SOS:
"There is a rubber gasket on the covers that prevent water from falling into this area. Sometimes, the covers are replaced upside down. Making sure the gasket is in place should eliminate this problem."
http://www.nsxprime.com/forum/showt...n-Rear-Coil-Bank?p=61013&viewfull=1#post61013
garyn:
"You might want to check if the cover for the coil and spark plugs is on the correct side. It should be RR for the rear and FR for the front(it's printed on the inside of the cover). Mines were reversed so the gasket was on the bottom. This let water in and it filled up inside the spark plug tube."
http://www.nsxprime.com/forum/showt...r-rain-or-wash?p=607022&viewfull=1#post607022
LarryB:
"make sure your coil covers are not on reverse. The rubber seal MUST be on the top on the intake side of the valve cover. If not water will get into the coil area."
http://www.nsxprime.com/forum/showt...vy-rain-storm!?p=805643&viewfull=1#post805643
BrianK:
"Make sure the coil covers have good gaskets and that they are installed properly."
http://www.nsxprime.com/forum/showt...rear-coils!!?p=1158639&viewfull=1#post1158639
ftuhy:
"Make sure the gasket is at the top. A common error is to install the cover upside down."
http://www.nsxprime.com/forum/showt...n-spark-plug?p=1337540&viewfull=1#post1337540
Edited to add: I just got curious about if this is easy to check. Indeed it seems to be something that can be checked in 30 seconds without removing anything. Grab some kind of rigid paper (3x5 index card, envelope, etc). Each silver cover has three humps, each about 2" wide. Slide a corner of the paper into the top of the hump (between coil cover and valve cover) - see how far it goes before stopping. Then do same at bottom edge of the hump. On mine the paper gets less than 1cm into the top before hitting something (presumably the gasket), whereas from the bottom it will slide at least 1 inch unimpeded by anything under the cover (no gasket). But if you're having issues...probably want to remove both silver coil covers - not just to check for this situation, but also to check that the gaskets are intact/sound.
. I took the covers off this weekend to add dielectric grease and didn't remember seeing gasket. Just took the front a rear covers off and no gasket on either and they were installed on the wrong side. So looks like I found the problem
