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Maintenance 101: 4.7L Exhaust Leak Repair

20K views 17 replies 6 participants last post by  Nubby 
#1 ·
#2 ·
Hey Jack,

I watched your video and finally mustered up the courage to do it to my 06' Commander. I went to the local Mopar guys and got the bolts and gaskets which wasn't too expensive. After about 5 hours I got the drivers side done and the passenger side took about 4.5 hours. Not too bad just no room to move and it can be frustrating. Thanks for the great video. I took a bunch of pictures I'll try to post them soon. I had 1 bolt on the drivers' side and 2 on the passenger side that were broken but luckily with a little PB blaster they came out with my vise-grips. I was worried that i'd have to pull a head, but thankfully I didn't have to. I loved firing it up and not hearing that darn leak. Hey, while I was at it. I took my dremel and polished the exhaust manifolds out! haha I'm sure i'll get about 2/3 of a HP out of it. Sure was worth saving $1200 bucks to have the dealership do it.

Jake:eek:hyeah:
 
#3 ·
Great video!
I take it there are a total of 8 bolts, 4 studs and 4 bolts? ( not counting the flange bolts)
Were you able to get at all of the bolts and studs through the wheel well?
Did you have to order the bolts and studs through the dealership?
Did you use any lock tight when putting the bolts and studs back in?
 
#4 · (Edited)
**** 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).
 
#5 ·
Thanks, I just went by the dealership and ordered the bolts and studs.
They did have some in stock but not all of them.
The studs he showed me already had some type of lock tight on them.
I am not sure he ordered the right bolts though. He said it took 8 studs total. From looking at the video there are 4 studs and 4 bolts.
I will see when I pick them up. Total price was $46.66 for the studs and I hope bolts (dealership) and $12.32 for the gaskets. (Oreillys)
The Haynes does show a torque value and torque sequence.
 
#6 ·
The studs he showed me already had some type of lock tight on them.
I bet that the new studs are new part number to fix this know problem, i.e. the coating is there to help prevent future studs seizing and snapping off.
I am not sure he ordered the right bolts though. He said it took 8 studs total. From looking at the video there are 4 studs and 4 bolts.
I have NOT done the job, nor do I have a 4.7L, but that doesn't sound wrong to me. Are you sure you're NOT thinking of just one side, and NOT doubling the numbers for both sides? 8 fastners per exhaust manifold sounds right for a V8 (2 fastners per port), only 4 fasteners per exhaust manifold sounds awful skimpy, but again I'm just guessing.

A quick google search showed this?
http://www.justforjeeps.com/macuor1.html#prettyPhoto
The Haynes does show a torque value and torque sequence.
Haynes are the worst of all the repair manuals. I do a google search, hopefully someone on this forum has a FSM that can tell you the exact torque sequence and torque specs.

They don't mention that on the Youtube video?
 
#7 ·
The factory manual I have gives:

Tighten all manifold bolts starting at center and working
outward to 25 N·m (18 ft. lbs.)

Heat shield nuts 8 N·m (72 in. lbs.), then loosen 45 degrees

front exhaust pipe/catalytic converter assembly to exhaust manifold bolts (2) to 26 N·m (19 in. lbs.) torque.



For part numbers I show PN 06508220AA Studs-4; PN 06507746AA Bolts-8; PN 06508219AA Studs-4. 8 fasteners per side with the bolts in the middle, longer studs on the two rear spots and shorter studs on the front.
 
#8 ·
I guess I am getting the right bolts and studs then.
My receipt shows the same part numbers.
My Haynes also shows the same torque numbers and torque sequence.
Hopefully I will be doing this on Thursday. I will get back to you when I am done.
 
#9 ·
Again, I haven't done this job, nor watched the video, but judging from the pictures of the hardware and the diagrams (as well as the torque specs) it doesn't look like these "studs" are true studs when it comes to the exhaust manifold?

If looks more like exhaust manifold bolts that have a stud extending out the top for the heat shield?

Do you remove the nut off the stud (the nut that clamps down on the exhaust manifold, NOT the heat shield)? Or is the nut portion on the stud permenantly attached, you bolt the studs in using the nut (permenantly attached) like a bolt head?
 
#10 · (Edited)
The nuts on the end of the stud holds the heat sheild. The studs hold the manifold. At least from what I can see.
Yes the nut portion is part of the stud. (perment)
Looking at my reciept again and I only show two part numbers.
4) 6508219-AA STUD DOUB 09004007
8) 6508220- AA STUD DOUB 09004007
I think they did not order the bolts. Part # 06507746 AA
I will pick them up Thursday but I have a feeling the parts are all wrong.
The guy behind the counter really did not look like he knew what he was doing.
 
#11 ·
Recieved my bolts and studs today.
Yes the order was wrong, they gave me too many of one of the studs and no bolts.
Luckly they did have the bolts in stock.
Total price for the bolts and studs was $50.18.
I will be doing this on Tue. and Wed.
Picture of the bolts and studs, as you can see there is some type of lock tight on the bolts already.
 
#12 ·
Also just extra info for anyone looking Dorman part numbers 674-911 and 674-912 are the exhaust manifolds for the 4.7L, includes the manifold, manifold gasket, heat shield and the manifold to exhaust pipe hardware and can be had online for under $100 each. Does not include the manifold mounting hardware. Also if you're not putting the heat shield back on then you can use just the bolts mentioned above in all 16 positions.
 
#13 ·
I just got done getting the drivers side exhaust manifold off.
This is a royal pain in the rear.
Most of the bolts you can not even see.
I did have one broken bolt. The upper one closest to the firewall. Once I got the manifold off I was able to turn it out with my fingers!
I had to walk away from it for today. I will put it back together tomarrow.
I really do not see being able to get my torque wrench on most of the bolts.
Passenger side looks much easier, there is alot more room.
We will see.
 
#14 ·
I really do not see being able to get my torque wrench on most of the bolts.
Passenger side looks much easier, there is alot more room.
We will see.
The proper torque is likely critical on these bolts, the exhaust manifolds heat is extreme, they expand and contract a lot, so too tight and the bolts may break, too loose and the exhaust may leak.

But getting within a few ft-lbs of the proper torque should still be good, especially if that is the best you can do.

Use a wrench or breaker bar that fits that is the same length as the torque wrench, or at least mark the length of the wrench/breaker bar that your going to use on the hard to access bolt on the torque wrench and apply the pressure with your hand on the torque wrench at that mark (if you're able, some torque wrenchs don't work this way). Pay close attention to the pressure on you hand as you apply the proper torque and then recreate the same pressure in your hand on the wrench/breaker bar for the harder to reach bolts. (you'd be surprised how close some people can come just by feel to the same torque as a torque wrench).

Another technique, tighten the bolts finger tight, note how much of a turn the bolts needs to reach spec torque (remember, after you tighten first one it will pull the manifold closer and you'll need to retighten all the bolts finger tight again, the remaining bolts will be your indicator as too how much turn). When you get to the bolts that the torque wrench won't fit, then turn the those bolts the same number of degrees as you did the others with the torque wrench.
 
#15 ·
Done with the drivers side.
I now have a different noise.
It is the muffler! :headbang: I had the wife rev the engine and you can see the muffler kind of pulse. Just in one area.
I am guessing that some of the baffles have come loose.
That is one big muffler!
I normally do not do mufflers. I will take it to a muffler place and see what it will cost to have it replaced then go from there.
 
#16 ·
I got my heads back and will start rebuilding the top of the motor. The Felpro gasket kit has new exhaust manifold gaskets but they're quite different than what I pulled off OEM. The OEM gasket has a thin piece of metal riveted to a squish type thicker gasket and appears as though it was build with some high temp RTV around the exhaust ports to seal up.

The Felpro exhaust gaskets are just the thicker squish type gasket and do not have the holes to rivet a thinner piece of metal to.

Should I even try the Felpro or just pick up new OEM?

Is it work using sealant (High temp RTV) on the gasket? Again, my heads are already off of the motor so space is not a concern for getting a bead on it. We use HTRTV on snowmobile exhausts all the time to seal them up and it works great. The difference here is a long term, torque fitting vs a spring tension motor with easy access down the road.
 
#17 ·
Is it work using sealant (High temp RTV) on the gasket? Again, my heads are already off of the motor so space is not a concern for getting a bead on it. We use HTRTV on snowmobile exhausts all the time to seal them up and it works great. The difference here is a long term, torque fitting vs a spring tension motor with easy access down the road.
If your gaskets came with instructions, follow them to the letter, that includes NOT using sealants unless it states to do so and then only exactly what they instruct you to use.

If there are no instructions, and the FSM doesn't have instructions, which the FSM instructions may be ABO since the gasket your using is different than the OEM. That is up to you, using sealants with gaskets is a 50/50 shot, they are just as likely to interfer with proper sealing as they are to help it. Use the proper sealant, go the sealant manufacturer website and see what they recommend for your type of gasket and application it will be used.

I can tell you I highly, highly doubt that it is going to recommend using Hi-Temp RTV on an exhaust manifold gasket. The exhaust manifold will be at a high enough temp to burn away even hi-temp RTV, which would probably result in poorer sealing of the gasket, than if you used nothing at all.

Typically, people use Copper Spray Gasket Sealant on flat exhaust manifold gaskets.
 
#18 ·
I've never had HTRTV melt on a snowmobile Y-pipe and it is the same, if not hotter, than the exhaust manifold on a V-8. Either way, I picked up the OEM exhaust gaskets for WAY more money. I'm sure the Felpro gaskets would have worked great but the OEM gaskets haven't been an issue for 118,000 miles.

The parts guy said the reason the part numbers for the three respective parts are different is because Mopar switched suppliers. So while the part numbers were superseded, the parts are the same. I guess this means folks may be referencing this thread around 8 years from now for the second time....hopefully I'm not one of them.
 
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