Exhaust Manifolds | Warped

[Fast69Mopar]

I've scheduled my rig to get the broken exhaust studs replaced with the mechanic here in my little town of 350. I've done business with him for decades and trust him w/o question.

I have a warranty on the truck, so it's not going to be too painful.

HOWEVER, he's not a fan of milling down the warped manifold. He says the studs will break again anyway. Same as if I were to go with shorty headers.

I hate to butt heads with him 'cause he's a good guy and a great knowledgeable, experienced mechanic.

Over the course of the last several years I have either milled or belt sander somewhere around 200 pairs of 5.7 HEMI exhaust manifolds. Once the stock manifolds have become warped and the bolts have broken and the gaskets are leaking the manifolds have already gone through the stress relieving process and are very unlikely to warp again.

If you install a new set of exhaust manifolds you will end up in the same place down the road. It is inevitable. It will happen. For all of the pairs of exhaust manifolds I have repaired by milling them or running them on the belt sander I have yet to have a single truck come back with an exhaust leak due to a warped manifold. Of course gaskets get old and fail and start leaking.

Out of all of the manifolds I have repaired, then removed them later on down the road, whether it be for engine work or upgrades, the largest amount of clearance I have measured on a milled/belt sanded manifold has been
.0037" which is nothing. I have pulled new exhaust manifolds out of Mopar boxes and had them measure .008" difference in flatness from one end to the other.

With that being said, none of them have come back with broken fasteners. NONE. And, most of them have been reinstalled with new OEM fasteners. I do use ARP bolts for my customers trucks outside of the dealership as well. When ARP bolts are not readily available I opt for simple Grade 8 fasteners from my local hardware store or Fastenal.

For the trucks that have had new Mopar exhaust manifolds installed I have seen them warp as soon as 6,000 miles but these came from trucks that were worked very hard. For the typical daily driver I have had a few of them come back as soon as 17,000 miles after having new Mopar exhaust manifolds installed. It sucks. That was in the early days though before I started milling the manifolds.

 

[Dodge 1500 4X4]

Grade 8 will pull the threads out of the head, they are to hard for aluminum, If the manifolds are resurfaced at a machine shop, and use OEM bolts that can expand and contract with the aluminum and cast iron it should be good to go for a long time.

 

[El Huapo]

Grade 8 will pull the threads out of the head, they are to hard for aluminum, If the manifolds are resurfaced at a machine shop, and use OEM bolts that can expand and contract with the aluminum and cast iron it should be good to go for a long time.

Any idea what grade the OEM bolts are? Some of us are a long way from a dealer. Just collecting data so far, in case.

 

[Dodge 1500 4X4]

Grade 3 or 4 plus the oem has stud and the nuts for fastening the heat shields and you can get them here at All Mopar parts.

 

[Scottyshortbus]

Thanks for all the info. I called ARP and they didn’t offer anything that had the studs for heat shields. The dealership quoted over $300. I’m going to try NAPA brand ($70 and in stock). Sounds like I may be ok since I had the manifolds machined.

 

[shadowhawk]

is there a definitive parts list for doing the repair yourself? Seems my 2016 popped a few studs 4k miles out of warranty

 

[shadowhawk]

ughhhh- I hate stealerships. they want to just replace the manifold if they do the work. That doesn't solve my issue long term. price they quoted is $960 a side. That includes a new manifold, bolts, and gasket. 3-4 hrs labor

 

[Tim Garceau]

ughhhh- I hate stealerships. they want to just replace the manifold if they do the work. That doesn't solve my issue long term. price they quoted is $960 a side. That includes a new manifold, bolts, and gasket. 3-4 hrs labor

You can order a replacement manifold and gasket for <$100. Usually, the bolt breaks flush with the manifold flange so you can get a good set of vice grips on it. If it's flush with the head then it's a little more tedius. You can find that out without digging by removing the heat shield. 95 percent of the time it's the top or bottom backside heat shield bolt(s) that break. Check all outside 13mm bolts and inside 10mm heads to find out which ones are still clamped.

 

[shadowhawk]

You can order a replacement manifold and gasket for <$100. Usually, the bolt breaks flush with the manifold flange so you can get a good set of vice grips on it. If it's flush with the head then it's a little more tedius. You can find that out without digging by removing the heat shield. 95 percent of the time it's the top or bottom backside heat shield bolt(s) that break. Check all outside 13mm bolts and inside 10mm heads to find out which ones are still clamped.

but the new manifold would be prone to warping just like the original, right?

 

[Tim Garceau]

Yes after X0,000 miles they are likely to repeat. If you have the downtime a machinist can true them back up on a mill or surface grinder.

 

[shadowhawk]

it's not like I'm going anywhere. now I need a machinist

 

[Tim Garceau]

it's not like I'm going anywhere. now I need a machinist

 

[Daddyhas2boys]

the story goes like this...there's prolly millions with the same issue and fca refuses to do anything about it...its 1000-2000 to repair at the dealership...do the math its not an easy fix and would cost fca tens of millions if not hundreds of millions to rectify this as a recall...what a shame...I personally had 5 out 16 bolts broke off 4 internally and 1 externally...but I did the repair myself and put on long headers...

 

[Pickles]

Lots of great info here......

Any idea on how shorty headers will react? Am I facing the same issue down the road (warping) and just spending 4x as much on shorties? No machinists close to me, and those that are within driving distance are quoting way too long for my truck to be out of commission.

 

[shadowhawk]

anyone have an aftermarket part number for the collector nuts and bolts? Stealer wants almost $85 for the set of 4.

 

[Daddyhas2boys]

There's really only 2 options....option 1 machine existing oem short headers and supposedly won't have the same issue again...option 2 install long headers as I did cheap aftermarket and never have the same issue again...so I have about 500 in parts 1 set of long headers, 1 cross pipe with y pipe assembly, with a flowmaster super 10, plus various fasteners and clamps...so this thing sounds mean as hell

 

[shadowhawk]

There's really only 2 options....option 1 machine existing oem short headers and supposedly won't have the same issue again...option 2 install long headers as I did cheap aftermarket and never have the same issue again...so I have about 500 in parts 1 set of long headers, 1 cross pipe with y pipe assembly, with a flowmaster super 10, plus various fasteners and clamps...so this thing sounds mean as hell

where did you get cheap long tubes? Everything I've seen is over a grand, and then fitment becomes an issue.

 

[Daddyhas2boys]

Ebay

 

[Daddyhas2boys]

so I think the super 10 is very aggressive with my long pipe set up, seems to **** people off while driving...lol...any recommendations to quiet it down super 50 or Flowmaster fx or .....

 

[Daddyhas2boys]

So...from ebay...at 25% of the cost of the top brand names what do I have to lose but install time...see pics