**** I haven't done exhaust manifold bolts on a Commander, I've done them on other vehicles/engines, so as general advice *****
If there are any TSB instructions or factory instructions that come with a "Kit", I would follow those instructions to the letter. Usually if you've got something that is a "fix" for a common problem, engineers have worked out a tested method for fixing the problem, follow that tested method to the letter to avoid the problem re-occurring. I.e. What exactly to use on the threads, torques, torque sequences, etc.
But, if you just bought the hardware, and there are NO specific instructions in the FSM or a TSB, then as a General Rule:
For exhaust manifold/header bolts use,
- On threads going into the head - Use Hi-Temp Red Loctite*
- On threads on studs that bolts go over - Use Anti-Sieze
If you don't have / can't find Hi-Temp Red Loctite, don't use regular red or blue loctite, it will just burn away and be useless, anti-seize would be better than the wrong loctite on the threads going into the head.
And yes, get the bolts/hardware from the Dealer, NOT just any old bolt (even heat treated bolts from the local hardware store). Those bolts are designed and treated for the exhaust manifold, most general hardware bolts, even those heat treated aren't correct and are far more likely to break or snap from the stress of the heat/expanding/contracting manifolds.
*Hi-Temp Red Loctite is not available in most stores, I had to order it off the internet. From loctite literature and advice on other forums, this is the stuff to use, its break away torque is much less than regular red loctite (i.e. you can unbolt it if you need too) and the holding strength reduces to pretty much the same as blue loctite after exposure to the heat of exhaust. Regular loctite burns away on exhaust bolts, it won't be there in a few hours. Even the Hi-Temp stuff, after a few years it will be gone to.
I would think anti-seize would be better than nothing, preventing the corrosion and seizing in the head of the bolts does help prevent them from snapping off in the future, and anti-seize would do that.
Just be aware that lots of anti-seize will lube up the thread and reduce the friction/torque to get the same clamping force. I.E. if your using a torque wrench on a bolt that has lots of anti-seize on it, the spec torque can actually overtorque the bolt, and a stud/bolt into aluminum heads? You can strip out the threads on the aluminum head, reduce the torque by 15%-25% if you use lots of anti-seize on bolts that have a dry thread Torque Spec. (unless it specifies in the torque spec its for wet/lubed threads, assume its for dry threads).
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Last edited by Mongo; 07-28-2014 at 11:01 AM.