[Tylus]

Every few months my car starts to run rough, lurches, basically acts like she needs a tune-up. Makes early morning driving a real nightmare, and sitting at a stoplight annoying as hell. It does this until the motor heats up, then basically no symptoms.

To fix, I go under the hood and tighten the intake bolts a hair. The car goes back to normal. Purrs nice and smooth, no more "missing" when stopped....etc.​

I know the intake bolt torque is ~9 ft-lbs (107 in-lbs). Problem is, every time I use a torque wrench, I get to about 7 ft-lbs or 80 in-lbs and the bolts just turn. It appears I need to draw the intake down more to get a complete "metal to plastic" seal...but, I'm scared of cracking the plastic, so I always quit while I'm ahead.

I've got 2 different torque wrenches, so 99% certain it isn't a tool problem.​

Question (s):

At what point is the intake o-ring compressed so that I can actually torque the intake bolts to spec? Anybody had luck with this? Does it ever get better?

Seems trivial, but it really gets old doing this.
​

Sadly, this sort of work is what I do for the Navy...but I only deal with metals at work. Plastic scares the hell out of me. Especially on the intake with such low torque values.


TIA

 

[TJGS]

Are you still under warrenty ? Have you ever had the intake completely off and inspected it for distortion or cracks ?

 

[Tylus]

still under the powertrain warranty...but no I've never had the intake off.

 

[nunya]

If you're bolts are turning with no resistance your threads are stripped either on the bolt or the bolt hole. That ain't good, seek professional help!

 

[cdahl383]

I agree, if the bolts just turn freely that's not good. If you're under warranty I would have the dealer take a look at it.

 

[Tylus]

you guys misunderstood

the bolts are not free-turning in their holes. the o-ring is still compressing. each of the bolts has ~80 in-lbs of running torque. They are drawing tight as I place torque upon them...it's just that I'm having to put more turns on them than I'm comfortable. with metal I'd just make-up the joint and be done. but this damn plastic!

At some point I'm hoping the o-ring will full compress and I'll get a "metal to metal" joint make-up...which will allow me to completely torque the bolts to 9 ft-lbs. I'm worried about potential damage to the intake. Plastic scares me, because that'd be an expensive mistake

 

[nunya]

you guys misunderstood

the bolts are not free-turning in their holes. the o-ring is still compressing. each of the bolts has ~80 in-lbs of running torque. They are drawing tight as I place torque upon them...it's just that I'm having to put more turns on them than I'm comfortable. with metal I'd just make-up the joint and be done. but this damn plastic!

At some point I'm hoping the o-ring will full compress and I'll get a "metal to metal" joint make-up...which will allow me to completely torque the bolts to 9 ft-lbs. I'm worried about potential damage to the intake. Plastic scares me, because that'd be an expensive mistake

Sorry for misunderstanding. I feel your pain with plastic your going to have to be very very equal with tightening. Myself I wouldn't do it. I'd take it somewhere.

 

[dodge man2]

I can't remember why, but I messed with the plastic intake on a car in the past, but I agree, the bolts seems very loose when you go to tighten them. Next time its running rough, an old trick was to spray carb cleaner around a suspected leak. The leak would suck in the carb cleaner and for a brief second, cure the lean condition and smooth out. This might help you narrow down the exact area that is leaking.

 

[TJGS]

Usually plastic parts with bolt holes have a brass metal insert embedded in the plastic to achieve metal to metal contact without cracking the plastic. I haven't really inspected our intakes and don't know for sure but if you remove the bolt completely from the hole, you should be able to see if they have the inserts or not.

 

[cdahl383]

Gotcha, misunderstood you there. I agree with the others, if you're not comfortable doing it for fear of breaking something I'd let the dealership handle it. It's under warranty so it'd be free and if they broke something it's on them.