Factory Grade 8 manifold bolts VS. hardware store Grade 8 bolts for the manifolds?

Question

This is on a Jeep 4.0

The factory ones have black coating, while the hardware store bolts have the yellow-ish coating. I hear that the yellow coating resists corrosion better. In any case, I'm going to coat them all with oil for long term protection. Also, there are two studs in the place of bolts at the first and last holes on the head. I was only able to find uncoated grade 5 bolts to install on them (they were metric and fine threaded). Is this acceptable? The bolts only torque to 23lbs.

What are your thoughts? Is there any difference whatsoever between these besides the coating? What are your thoughts about the Grade 5 bolts on the end studs?

Hank Scorpio · Accepted Answer

The coated bolts are acceptable, the grade 5 bolts are not.  You don't want a leak on an exhaust manifold because in most cars they can be a pain in the *** to get to, and then you should retorque all the bolts again...  Use the factory bolts on the studs if you can't find a replacement.

Pedal2TheMetal45 · Answer

HI
NO on the grade 5 bolts..  must be grade 8 or better... 
If you go to a auto parts store or a fastener store it would be better to get the right stuff.
good luck
tim

kelly_f_1999 · Answer

any parts store would be best but  what coating one as doesnt mean much

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Factory Grade 8 manifold bolts VS. hardware store Grade 8 bolts for the manifolds?

3 Answers