Cracked intake manifold! Check yours!

[TanStewie]

The intake manifold assembly that goes between the air filter and the throttle body is cracked on my 4.0. Appears to have been over tightened (at the pipe clamp) either by the factory or previous owner, this caused it to crack.  A piece of plastic about the size of my thumb broke off at some point and I can only guess went into the intake, and has either been chewed up by the engine or is about to be. So my engine has been sucking unfiltered air for who knows how long, while I've been on countless dirt roads. I'm pretty bummed. Just noticed this while changing the oil and getting ready for a trip.

I'm going to order the replacement part, but should I pull the whole intake manifold plenum off and try to see if there is debris and try to find the missing plastic?  Do you suppose the missing piece of plastic has already gone through the engine?  I'm worried its going to wreck my engine if it hasn't already.

Edited September 16, 2017 by TanStewie

[radin2son]

Thanks for the heads up... it makes you wonder if stress is put on this area when changing the air filter. Probably not.

 

Can you determine how much air is being sucked in? As in use plastic wrap or thumb to see if it pulls in enough air to suck in the piece of plastic Is the air filter too clean for the miles driven? Both may help decrease/increase your concern about damage and next step.

 

Car Talk had all sorts of stories about things being sucked into engines and generally they felt things burned up and just drive it. What can you do but drive it...

[TanStewie]

It was hole about the size of my thumb, sucking in a lot of air.  I pulled the throttle body off and there is a honey comb type thing in there to prevent anything large from being sucked in.  So the piece of plastic must have fallen out some how, there's no telling.  There's no way it could have gone into the engine which makes me feel better.  I sealed the whole thing up real good with some 3M putty tape and its fine for now.  The part from nissan 16576-1PE0A is $126, I ordered that and should have it in about a week.

 

I'm bummed by the fact that is was sucking in unmetered/unfiltered air for who knows how long.  But it seems to run fine so I'm not going to worry about it.  

 

But anyways, I would take a close look at the intake especially the rubber hose connections and make sure you dont have any leaks.  It wasn't enough to trip a check engine light or anything like that.  

[radin2son]

Thanks for the follow up.

[Ferrugenfish]

Thanks for sharing.

 

And side-note... lemme know if any of you find an aftermarket Air Intake that actually fits!