MarineBSP
Senior Member
My 2018 Laramie CC with 5.7L Hemi suffered the most common broken rear-most exhaust manifold bolt on the passenger side (PS) ten months ago. But with < 60K miles, my dealer replaced the manifold and hardware under warranty. Only the bad side was replaced, and since it was a warranty job, I could not keep the old manifold.
I figured I’m on borrowed time for the driver’s side (DS), so I purchased recycled OE exhaust manifolds, both DS and PS, hoping these will be well heat-cycled. A local machine shop flattened them for me, and the mating surfaces are very good. I plan on swapping out both sides (hopefully without broken bolts on driver’s side). I’ll crack the bolts loose working back from the front to have the least stress on those back bolts when I loosen them. I have new gaskets & hardware.
My question for the forum of wisdom, knowledge, & experience (yeah, opinions too):
There are some bolt length differences in OE bolts. A running change added 5mm to the bolt lengths after my truck was built (from 06/2018 on). Is that just to accommodate the tie bars they added back then? The bolts went from 50mm long to 55mm long. I have 55mm ARP bolts and Mopar bolt-studs, but I’m concerned in case the holes in the head are not deep enough or threaded deep enough. I will probably be OCD and run bolts in without the manifold and gasket to check this. If I were the design guy, the threaded holes would have a safety margin . . . But after resurfacing, the middle of my “new” manifolds will not have as thick a shoulder. If needed I’ll add lock washers (okay idea or not ?). This is the difference between doing this job once-in-a-lifetime versus three times a week as a part of a shop’s regular work load.
I won't get to the job for a week or so because of Fall cleanup, but I'l post when done.
Thanks for input.
I figured I’m on borrowed time for the driver’s side (DS), so I purchased recycled OE exhaust manifolds, both DS and PS, hoping these will be well heat-cycled. A local machine shop flattened them for me, and the mating surfaces are very good. I plan on swapping out both sides (hopefully without broken bolts on driver’s side). I’ll crack the bolts loose working back from the front to have the least stress on those back bolts when I loosen them. I have new gaskets & hardware.
My question for the forum of wisdom, knowledge, & experience (yeah, opinions too):
There are some bolt length differences in OE bolts. A running change added 5mm to the bolt lengths after my truck was built (from 06/2018 on). Is that just to accommodate the tie bars they added back then? The bolts went from 50mm long to 55mm long. I have 55mm ARP bolts and Mopar bolt-studs, but I’m concerned in case the holes in the head are not deep enough or threaded deep enough. I will probably be OCD and run bolts in without the manifold and gasket to check this. If I were the design guy, the threaded holes would have a safety margin . . . But after resurfacing, the middle of my “new” manifolds will not have as thick a shoulder. If needed I’ll add lock washers (okay idea or not ?). This is the difference between doing this job once-in-a-lifetime versus three times a week as a part of a shop’s regular work load.
I won't get to the job for a week or so because of Fall cleanup, but I'l post when done.
Thanks for input.