When I tightened my engine cover yesterday, all except the rear bolts never seemed to get tight. I'm guessing I used about 15 ft-lbs of torque or so when I tightened them. When I subsequently tried to remove them, they just spun indefinitely without backing out, even when pulling upward while unscrewing via vise-grip. I'm kicking myself, as those bolts were basically the only bolts for which I didn't use a torque wrench. To my belated understanding, the only bolt that really matters is the center one, as that's the one that can compromise the plastic upper intake manifold/plenum.

To remedy the situation, I recommend the OEM engine cover remover. If your dealer doesn't know to what you refer, let them know it looks just like a Friskars, and that should let them know how best to provide service to you.




After encouraging the engine cover's removal, I cut away at the center bolt's o-ring-esque rubber, and was able to get just enough of bight via vise-grip on the engine cover's washer-like metal backer that otherwise spun freely with the bolt while unscrewing the bolt with a socket....
...that inexplicably worked in allowing me to remove the bolt, which doesn't make sense to me since that wouldn't hold up the bolt I wouldn't think.

Vise-grip is biting on the engine cover's washer-like metal backer, not as it may perhaps seem on simply the bolt's washer.





Once ACE Hardware is open this morning, I plan to get a replacement center bolt at half the length of the OEM one, add some blue threadlocker, and see if that's sufficient to salvage the plenum. I'm concerned the entire metal insert in plenum may be compromised though, so I'll likely add silicone sealer around it.

In the bolt pic, center bolt is in the foreground. The two bolts in the upper area of the photo are the two rear bolts that were removable without issue. You can see the vise-grip markings on the engine cover's metal backer. The center bolt does not appear be stripped. I'm concerned the plenum's entire metal insert may be what was spinning freely, since why else would an unstripped bolt spin freely without being removable? (Perhaps when I vise-gripped the metal backer perhaps just a tiny amount gripped on the plenum's entire metal insert to resolve the situation. But I don't see any vise-grip markings on the insert.)









Side note: Engine cover for sale. Minor assembly required. No lowball offers, I know what I've got. Glove fragments included at no extra charge.

 

Too bad you had to cut up one of the few remaining engine covers that still have the Infiniti logo.
Good luck with the sale

 

I kept the chrome Infiniti logo, somewhat inadvertently since it popped off on its own when encouraging the removal of my engine cover.

With regard to availability, the engine cover, albeit sometimes only with the void for the logo, appear to be readily available on ebay? Random example. Not sure if I'm going to bother to get a replacement cover though.

 

There is no need to replace the engine cover. Its purpose is to reduce mechanical engine sounds (like ticking fuel injectors) and to make it look nicer under the hood.
My engine cover has removed for the last 4 years.

 

What is ironic is that the JDM Nissan emblems- for these same covers- are made of metal and have tabs to hold the emblem intact. Infiniti uses the cheap plastic that pops right off... go figure.

 

Got back from the hardware store. Used the shorter of the two options I bought, added some blue threadlocker, and lightly hand tightening with a just a socket showed that indeed the metal insert in the plenum spun rather readily. Accordingly, with the bolt only half inserted, I surrounded it with what I had on hand (Zap-a-dap-a-goo), very lightly tightened down with a readily cleanable open end wrench, and then rather liberally slathered additional goop around the bolt head edge / metal insert edge area.

After 24-36 hours for the goop to cure, I'll take it for a short drive to redo the engine idle relearn process, and see how things then fare. I won't be replacing the engine cover for at least the immediate future, but perhaps a replacement upper manifold / plenum may be in my future..

 

Really? Why do they always get the good stuff!

 

Nice job, that repair will last forever.

 

Hopefully. Though this is the first time my mint bone stock (except straw-modded sunroof drains) G37 is no longer mint bond stock. It's kind of an odd feeling to have it now bubba'd, in a blatantly obvious spot to boot. I guess I need to embrace the fact that it's over a decade old at this point. My near future plans to drop in a VR transmission be stepping off the precipice anyway.

 

Don't beat yourself up over this... 99.9% of the people looking at your engine won't notice.
-AND- if they do, tell them you installed a "cryogenic intake cooler"

 

If ya want to send that rare emblem to someone who would take care of it with great care I'll love to have it lol .

 

lol. Since my circumstance would essentially require a replacement plenum should I ever wish to again have an engine cover, I should probably indeed sell it. Send me a PM should you indeed be interested in buying it.

 

Everything's copacetic now... when the engine is warm. When warm, it purrs like a kitten at ~600 rpm in D (notch higher (as always, just like before) in P). With low AC I can't even tell it's running. (Interestingly, this is about 500 rpm, I'd say, lower than what it was the past 8 years I've owned the vehicle, before I changed the spark plugs, cleaned the throttle bodies, had my plenum fun and fix, and did the engine idle relearn process after a short drive.)

Oddly, uncomfortably high ~1500 rpm idle when starting up cold though (summertime ambient). Not sure if this means I should redo the engine idle relearn process when the engine isn't quite fully warmed up. Or perhaps if this may mean the Zap-a-dap-a-goo does a good job sealing the plenum leak when a bit warmer and pliable but less so when the engine is cold. Or some other fact I'm not considering. Not sure, but been just living with it for now even though the in D foot-off-the-throttle experience is a bit eyebrow raisng at ~1500rpm vs a more normal 750-600rpm.