View Full Version : Just a reminder to check your intake manifold bolts

01-06-13, 04:24 PM
Just thought I'd throw out a friendly reminder to check your intake manifold bolts on your Northstar. I checked mine while finishing up the coolant flush. Found all of them except 2 where loose. In fact one had backed out approximately .125 in. It did seem to smooth a little roughness I felt at idle.

01-06-13, 04:31 PM
Common issue that often causes rough idle at first daily start but doesn't set SES light or codes.

01-06-13, 04:44 PM
Yep, I have read about it plenty of times. Just thought i'd throw the reminder up to those that may be new to the forum or have forgotten about it :)

01-07-13, 03:24 PM
I had this prob with my 05. I haven't checked my 08. I don't feel any issues at the moment. Did every N* have this problem?

01-07-13, 03:38 PM
From reading this forum and having to do it twice on my 06, I would say it could have to propensity of being a universal problem with this generation engine.

01-07-13, 03:51 PM
I just did mine, It gave me +++ miles per gallon.
AND great pickup.
I really want to put "LOCK-TITE" on the bolts
to prevent them from loosening AGAIN.
But No one on here has the experience on
How to pull the fuel rails ! Including ME.
Happy Motoring. :cool2::cool2::cool2:

01-07-13, 08:21 PM
My wife's 2007 has needed attention but my 2006 has been fine.

Evidently, it simply varies from car to car.

01-07-13, 08:30 PM

I will be looking into this, i will post up pics and lessons learned. Let me see if i can get some more info on it from alldata this evening.


Just took a look at Alldata, it doesn't look too overly complicated, actually pretty simple. Since the injectors aren't going into a high pressure area, i'm guessing it is probably a simple o-ring that seals the injector to the manifold. But basically the gist of it was to un-bolt and lift off. I didn't see any special tools. There is a specified sequence for tightening the manifold. Which I didn't follow when snugging them up the other day. I didn't check alldata first.

I think my next purchase might also be a set of the Helms manuals as well.



01-07-13, 09:09 PM
As I recall all the posts on the manifold bolt issue, the specified torque specs are pretty low and some members have seriously over-done it without adverse consequences. If I had a persistent case, I'd use of Locktite. Now that they have various grades, I'd start with new bolts and the lightest grade. If the issue appeared again, I'd move up a grade but always use the right torque.

Members, chime in!

01-07-13, 09:22 PM
Last I heard, On here,it was 89 in/lbs,
as it is a (plastic) type manifold.
the sequence (IS) on this forum.
We have Direct Injection,Into the cylinders ?
As opposed to Port Injection,(Fords)into the Intake manifold !
Thanks for the info on pulling the fuel rails !

01-07-13, 09:42 PM
The N* is NOT DI.

01-07-13, 11:22 PM
Yep, NOT a DI engine.

You basically remove the emissions tubes from the manifold, disconnect the electrical connectors from the fuel injectors, relieve fuel system pressure, disconnect the fuel line from the rail, and it looks like 4 bolts holding the rail to the manifold, and then lift it off. The torque for the intake manifold to the engine is 89 in-lbs, as is the torque for the fuel rail to the intake manifold.

Actually the starter is under the intake manifold, so if you ever have to replace that the rail and manifold need to come off.

01-08-13, 09:21 PM
Who knew?

Maybe they aren't being torqued correctly to begin with.

01-08-13, 10:28 PM
Who knew?

Maybe they aren't being torqued correctly to begin with.

They are probably being torque correctly, but chances are it is a tapped hole in the block it goes into and likely no locking element is used. I know there is no spring washer or anything of that nature on the bolt. After some duration of vibration at various levels they are destine to come loose. Also, I don't recall if there was a metal insert in the thru hole for the manifold. If not, you may get some cold flow from the plastic causing an eventual loss of preload on the fastener and therefore no clamping force and the ability to be easily backed out with small vibration.

01-09-13, 02:50 PM
Put a fine witness mark with a felt-tipped marker on the head of each bolt, oriented in such a uniform manner, that if one or more turns from vibration, the marks will be out of alignment.

01-11-13, 10:14 AM
If I'm correct, the torque setting is 10 ft. lbs. or 120 in. lbs. and whats wrong with using a drop of blue lock tight on the bolts. Just don't use the heavy duty (dark red) lock tight. The bolts might break off if the manifold has to be removed.

01-11-13, 02:21 PM

I posted the torque above, all data lists it as 89 in-lbs. That is for an 05, dont know if 07+ would be more.

I think blue loctite would be fine on these fasteners