Exhaust Manifolds | Warped

[OCDTech]

Wow, thanks for that info, i did see the crazy gap in the pics, and thank you for being a good tech, i am a technician, not automotive, but i always try to find the cause of an issue and fix from the get go, its just what your supposed to do. I've always enjoyed fixing things, i tell my "younglings" /helpers it s like being a detective sometimes.

 

[Wild one]

The old FE 360/390 Fords were famous for warped exhaust manifolds back in the 60/70's,warped manifolds are not really a new Hemi specific problem.The 4.8 and 5.3 GMs also warp manifolds and break bolts on a fairly constant basis too.

 

[OCDTech]

The old FE 360/390 Fords were famous for warped exhaust manifolds back in the 60/70's,warped manifolds are not really a new Hemi specific problem.The 4.8 and 5.3 GMs also warp manifolds and break bolts on a fairly constant basis too.

Now that you mention it, in that same line of engines, i had a 6.0 chevy work truck we bought with 44,000 miles, ticked, i looked back exhaust manifold bolt driver side broke off.

 

[Wild one]

Now that you mention it, in that same line of engines, i had a 6.0 chevy work truck we bought with 44,000 miles, ticked, i looked back exhaust manifold bolt driver side broke off.

About 2/3's of our company's fleet of 4.8 and 5.3's have had the manifolds resurfaced and the bolts replaced at well under a 100,000 miles.The shop we take them to,jerks the manifolds off and sends them out to be re-surfaced /flattened and they never give any issues after that.

 

[Hcamper]

How many miles does this usually happens?

 

[madtrucker2016]

Not sure if this is relevant but I'll share just in case - 2014 6.4 Hemi 2500. At about 85K while going in for a routine oil change I mentioned that my truck seemed to be a bit loud in the morning when starting up. They call and tell me both exhaust manifolds have bad bolts and need to be redone. I have a lifetime Maxcare warranty so for the $100 deductible I say sure... replace them.

So, I go get my truck and when firing it up the first morning it sounds just the same. Basically, what I was hearing wasn't the manifold bolts. It really sounds more like just loose exhaust mounts or something. More of a rattle further away from the engine. Of course, I was skeptical if they actually did anything or just milked the warranty company but did see signs of a lot of work - grease stains, new nuts and bolts, etc.

I guess the only thing that could be relevant to your cause is that I never heard any tick or spoons rattling in cans but was diagnosed with bad manifold bolts.

check the cats could be falling apart they make a rattle sound

 

[Pull Ya]

This thread has some great information in it and IMHO should be referenced when any question about broken manifold studs or warped manifolds is asked. Thanks to the guys that chimed in on this problem and shared their experiences. As common as this problem seems to be maybe this thread should be a "sticky" so people could reference it.
Jay

 

[Fast69Mopar]

This thread has some great information in it and IMHO should be referenced when any question about broken manifold studs or warped manifolds is asked. Thanks to the guys that chimed in on this problem and shared their experiences. As common as this problem seems to be maybe this thread should be a "sticky" so people could reference it.
Jay

Thanks Jay. If there is something I can contribute to the forum that will help a fellow Mopar owner I'm all for it. I've been around and with Chrysler for a long time and have seen so many different scenarios.

@Hcamper, I have extracted broken exhaust manifold bolts from engine with 11,000 miles and I have seen 5.7 HEMI's with over 200,000 miles on the clock that have never been in a shop before. It is a crap shoot.

My best advice to anyone with a HEMI, as soon as you hear that exhaust leak don't wait to get it repaired. The longer the gasket is leaking the harder it can make the extraction. The sooner the better. If you have to pay a shop to do the repairs inform them that you want to machine the manifolds instead of replacement. Have them removed and take them to your local machine shop. Once they are milled or belt sanded and the stress has been relieved they will be good to go.

 

[68PowerWagon]

I see warped 5.7 HEMI exhaust manifolds all the time. Here are a few pics of the last set I milled from a 2004 DR that I bought. As you can see in the pics one of the ports on the end is flat and the other end of one manifold has an 1/8" gap showing light and the other had a 3/16" gap.View attachment 191584

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Holy crap that is bad! Appears to be at least a 1/16". From what I have been told, it doesn't take all that long for them to warp after a bolt has been broken.

 

[68PowerWagon]

I took it into my local dealer to have them examine the truck and after about an hour and a half they came back with the news that both exhaust manifolds are "warped" and have got to be replaced. When I asked if the truck had a bad lifter, they said that upon initial inspection, their tests showed that all the lifters are operational and moving as they should but, they wouldn't know for sure until the vehicle is dismantled.

I would think they could do a cylinder leak down test to see if the lifters are not working properly. And would be a lot easier to do with the manifolds off.

 

[ChevySlayer69]

Not sure if the OP has made a decision, but it seems to me highly unlikely that a lifter started failing simultaneously as the truck showed the exacts symptoms of manifold bolts breaking... followed by the inevitable manifold warping since it wasn't fixed quickly.

 

[Fast69Mopar]

I would think they could do a cylinder leak down test to see if the lifters are not working properly. And would be a lot easier to do with the manifolds off.

A cylinder leakdown test won't show any significant leakage unless the lifter has already begun to fail and the lifter is either collapsing or the roller has already seized and taken some material off of the cam. By then you would already have a loud noise and a misfire.

 

[Fast69Mopar]

Holy crap that is bad! Appears to be at least a 1/16". From what I have been told, it doesn't take all that long for them to warp after a bolt has been broken.

One of the manifolds was 1/16" and the other was almost 3/16".

These manifold had been on and off of this motor many times before I bought the truck and the bolt holes in the heads were severely damaged to the point that I had to Heli-Coil every single bolt hole. The people who were wrenching on this truck did some very shoddy work.

 

[Dpressed1]

How many miles does this usually happens?

Just did a 18 with 23k miles that had broken bolts.

 

[Dpressed1]

And i put a straight edge on the manifold before reinstalling, took your tips Fast69Mopar, no warping found!

 

[Marshall]

This is stunning to me. I've never had a car that's had this problem before, or that had it as such a prevalent issue across the model. I wonder if the warped manifolds are due to poor materials or a bad design. I guess what I'm wondering is, if a technician sees warped heads all the time, I wonder how often I'll be looking forward to this repair, you know?

Sent from my SM-N950U using Tapatalk

As a old bugger, I can't believe a mechanic never seeing a warped manifold, Really? Guess they never check. I have not done the new hemi, but worked on lots of small and big blk. over the years, If you did a motor , you as a rule planed the manifolds, most of the time they are warped.. Sometimes would use a belt sander, if it was a hi power big blk, I usally had them machined. 318-360's where always high on the out side ends.

 

[Fast69Mopar]

And i put a straight edge on the manifold before reinstalling, took your tips Fast69Mopar, no warping found!

Good work man. So far I have not had a pair warp any more after belt sanding or milling with a fly cutter on the Bridgeport Mill. And just like you did I always use my Snap-On straight edge to verify after the manifolds have been completed.

 

[autumnwalker]

Curious about the better route here - do you resurface the old manifold (as seems to be a permanent fix) or would you be better off getting some headers. Are there enough performance gains or other benefits to headers over the manifolds to make it worth the upgrade?

What about the bolts? Are the factory bolts sufficient for a set of machined mainfolds / aftermarket headers or should the bolts be upgraded as well?

 

[68PowerWagon]

One of the manifolds was 1/16" and the other was almost 3/16".

These manifold had been on and off of this motor many times before I bought the truck and the bolt holes in the heads were severely damaged to the point that I had to Heli-Coil every single bolt hole. The people who were wrenching on this truck did some very shoddy work.

Wow... sounds like some flunky that got fired from Wal Mart Tire & Lube was working on it. To have to have that done to every hole somebody REALLY didn't know what they were doing. As others have done, they would have been better off buying headers & all new bolts & been done with it. Sounds like they changed bolts more often than they changed oil!

 

[68PowerWagon]

A cylinder leakdown test won't show any significant leakage unless the lifter has already begun to fail and the lifter is either collapsing or the roller has already seized and taken some material off of the cam. By then you would already have a loud noise and a misfire.

Well you would think it would be noisy & misfiring but I have seen some pictures of cams on here that looks like they have run it for several months with the lifters not working properly. Damn near rounded the lobes off. I would think after just a few thousands were taken off the lobes you would start getting misfires.