So here I am at Mufflertech in Sacramento installing a new Magnaflow muffler before I drive 1300 miles to Colorado Springs. The job took 20 minutes, and came with hefty $1700 price tag since the tech found that BOTH my engine manifolds were cracked BOTH!!!! Such a nice surprise to encounter two days before I leave town. The worse thing about it is, there were no indications that I had this problem!! No lights came on, nothing!! I am grateful that I found this out before I began driving, since I am driving with my family, but D*** couldn't this happen 4 months ago??!! There is nothing like perfect timing.

You can have crack manifolds and never get a code. How many miles on your vehicle? The emission is 8/80 which the manifold falls under because the cats are a part of it.
Also a set of aftermarket headers would have been much cheaper.

I have 115,000 miles so I was out of luck on the warranty point. A set of aftermarket headers may have been cheaper, but I hit the road Friday morning and I'm on a set schedule. I had to get the leak fixed and right away and given my options, I unfortunately didn't have much time to shop around on the internet or anything. The quote I got, believe it or not was the cheapest I heard today. Another place quoted me $3,000. Not saying that I'm happy with the cheaper quote by any means, but man!!!! WTF?? I do wish I could've went with a cheaper option.

So what's to stop it from happening again? The early models are known to have this issue right ... because of the weight put on the manifolds by the cats? For those who have replaced their headers when this happens, are you adding a hanger or anything to keep them from cracking again?

That's a good point tchjts1, I may have to do some research and possibly talk to a dealership about possible remedies to help support the cars for the cracked manifolds. Once I get to Colorado that is.

I don't want to hijack this thread, but what are some of the warning signs that you have this issue. I see alot of people that have had this issue and want to see if I should get it check out prior to the 8/80000 runs out. I still have about 20000 left to go, but don't want to wait. Any advice???

There are no warning signs. You have to keep listening for a clicking or popping sound. You will first notice it when driving close to a wall , etc. The sound bounces off the wall, and is much more noticeable then.

... want to see if I should get it check out prior to the 8/80000 runs out. I still have about 20000 left to go, but don't want to wait. Any advice???

You can probably get your dealer to do a courtesy inspection at no cost to you.
My dealer will take a look at just about anything for free, as long as it doesn't require much wrenching time to get to it.

You may get the "Service Engine Soon" (SES) light, you might get some ticking, then sometimes you hear or get neither. There are levels of manifold cracks. Both times I got the SES light. First one was covered by warranty and the second one I paid to have done!

You may get the "Service Engine Soon" (SES) light, you might get some ticking, then sometimes you hear or get neither. There are levels of manifold cracks. Both times I got the SES light. First one was covered by warranty and the second one I paid to have done!

So Spyda.... as someone who has had them replaced twice, have you done any modifications to support the weight of the cats so it doesn't occur again?

There is no SES light that comes on but there is a Tic, Tic, Tic that is there, very rhythmic, with the engine, so I have thinking it is from the lifters, cold, hot, doesn't matter about temp, always there. I just see all these owners with this problem and don't want to get the hugh bill to get it fixed if it may be there now and under thier cost. Thanks for the help

There are no warning signs. You have to keep listening for a clicking or popping sound. You will first notice it when driving close to a wall , etc. The sound bounces off the wall, and is much more noticeable then.

I noticed mine when driving out of my neighborhood. Everytrime I drove by a parked car I would hear the tapping I thought I had a valve tap at first ) . I also heard it when I started it. Once the engine was warm the tapping would go away.

HEY! im hearing what sounds like valve tapping... just as davidw and blood stated. i thought it was just cold engine and valves tapping.. i have an 08 LE 4X2 41K ish miles. so this could indeed be cracked manifolds huh?

so my next oil change is due in 2 weeks ish so ill have them smoke that over. so im asking them to inspect the "manifolds" correct? thats the proper terminology?

its not loud.. barely there... and it sounds closer to the engine... i hear it coming form the front driver wheel well.. well i only hear it there because i get in the car on that side :D. sometimes its there sometimes its not..(i dont always listen and i dont usually get out of the car with it running... usually when i get out the car is not running) so if they are broke are they always ticking/tapping or just at warm up?

so is this a loud sound? do you lose power or anything by these being cracked? by thee being cracked, whats being hurt/damaged?

So Spyda.... as someone who has had them replaced twice, have you done any modifications to support the weight of the cats so it doesn't occur again?

I only had one replaced under warranty and then the other about 40K later. I went with the OEM stuff and did not mofify it at all except that O have a Titan exhaust from the cat back that was cut to fit. I get a real growl now!

There is no SES light that comes on but there is a Tic, Tic, Tic that is there, very rhythmic, with the engine, so I have thinking it is from the lifters, cold, hot, doesn't matter about temp, always there. I just see all these owners with this problem and don't want to get the hugh bill to get it fixed if it may be there now and under thier cost. Thanks for the help

Our overhead cam engines don't have conventional lifters, so I don't think that is the source of the noise.

My Armada now has 58k miles. @ ~55k miles, my wife noticed a ticking sound at startup. As the engine warmed up, the tick sound mostly (sometimes completely) went away. I knew one of the exhaust manifolds was cracked...dealership confrmed it was the passenger side, and they replaced it free under warranty.

I am wondering honestly if the OP's manifolds have been cracked for a while.

So who has upgraded to headers? If so, what kind, and would you do it again? If my driver's side cracks when the warranty goes out, there's no way I am buying OEM manifolds. Grr.

As most are indicating, the exhaust headers on the Armada manifolds are flawed. It does appear to be caused by the weight of the cat, but I'm also not sure putting in a hanger would solve the problem.

I pulled mine and went back on with Stillens knowing that replacing them with the OEM meant I'd have the problem again. I caught the Stillens on sale, less than $600 for the set. The issue you'll have going after market is no cat, which means you'll need to either use the off-road fake O2 sensor (not recommended) or relocate the O2 sensor to aft of the B-pipe cats. That's the route I took. While it's a bit of a pain, you don't have to worry about emissions and all of that.

You'll want to get the long headers so the manifold will mate up with the B-pipe.

It took me a full weekend to do the job. I wouldn't recommend doing it yourself unless you regularly work on your car and have done something similar in the past. I got caught by some gotchas as well. If I did it again, it wouldn't take nearly as long, but I can see why a shop would charge a fair bit for the work.

^ wow $600 for Stillen headers seems like a good deal considering the best prices I've seen for OEM manifolds are ~$750.

Did you notice a power increase? If so, where in the RPM range did you feel it? How much more noise did you hear inside the Armada when all the windows were up while cruising?

Sorry for all the Q's, but this could help a lot of folks who WILL at some point be in this boat.

As most are indicating, the exhaust headers on the Armada manifolds are flawed. It does appear to be caused by the weight of the cat, but I'm also not sure putting in a hanger would solve the problem.

I pulled mine and went back on with Stillens knowing that replacing them with the OEM meant I'd have the problem again. I caught the Stillens on sale, less than $600 for the set. The issue you'll have going after market is no cat, which means you'll need to either use the off-road fake O2 sensor (not recommended) or relocate the O2 sensor to aft of the B-pipe cats. That's the route I took. While it's a bit of a pain, you don't have to worry about emissions and all of that.

You'll want to get the long headers so the manifold will mate up with the B-pipe.

It took me a full weekend to do the job. I wouldn't recommend doing it yourself unless you regularly work on your car and have done something similar in the past. I got caught by some gotchas as well. If I did it again, it wouldn't take nearly as long, but I can see why a shop would charge a fair bit for the work.

What are the specific troubles you had installing the headers? Would you mind uploading some pictures so we can see where you put O2 sensor.

Is there a part number to where you got them so cheap?

Euro - I just happened to catch the stillens when they were having a sale. A pretty good one. Bought them direct. I think I spent about $1000 total between the headers and the cats and other things I needed.

The descriptions given for the noise so far in this thread are very accurate. Drive next to a wall and see if you hear the noise. I had both manifolds leaking when I pulled them, so the sound was noticeable even with the windows up, but it wasn't too bad. And it came and went: it was worse when the engine was cold, but would go away after it warmed up. I'm sure it was consistent based on what the engine was doing, but it seemed fairly inconsistent to me.

I have noticed a bit of a power increase, but honestly not all that much. It seems to be across the board, though. I've been taking it easy until I get the ECU retuned, however. I'm thinking with the hi flow cats and these free flowing headers, I've bumped the power up a bit, but I don't have any idea how much. My concern is she'll run lean at WOT, so I'm trying to keep my foot out of it until I get that done.

Dustoff - One problem I had was a conflict between the shop manual and the instructions that came with the headers on removing the old manifolds. Stillen said to loosen the engine mount bolts and raise the engine; the shop manual didn't mention anything about removing the engine mounts or raising the engine. It wasn't until I had them loose that I found out why: the shop manual says to *remove the studs from the engine block* to get the headers out.

Uh, no.

So then I raised it per the stillen instructions, and it went pretty smooth after that.

The other issue is the sensors. On the replacement headers, the A/F sensor port is further down, which means you have to add some wiring so the sensor will reach the new port. The same has to be done to the O2 sensors.

For the O2 sensors, they need to be downstream of the cats, which means putting them behind the cats on the B pipes, and there's not a whole lot of room between the back of the cats and the flange, but it's doable. I ordered the O2 bungs off of ebay and had a welding shop put them on. Had to do it twice, though, because I wasn't thinking when I located the holes, so the sensors wouldn't go in because the truck floor was in the way. You definitely want to lay the b-pipes under and carefully consider how far the sensors stick out so you get a good placement. Obviously you don't want them sticking down, so your choices are limited. I have mine pointing to the center of the truck, running parallel to the truck floor.

To plug the existing bung holes on the cats, you can use an oil drain plug, either 13 or 15 mm, I forget which. But use a hi temp loctite or those suckers will work themselves out and you'll think all hell has broken loose under your truck! My cats came with plugs in the ports and you can just loctite those in place since you won't be using the existing ports.

I'll get under it and take some pictures as soon as I can. Might be a few days or maybe the weekend before I have a chance.

A couple of other notes: The wiring extensions on the sensors should be done on the harness side, not the sensor side. Otherwise you'll have to do the wiring extension again if you need to replace a sensor. I think it might also change the characteristics of the sensor, but I'm not at all sure about that.

For the cats, I just did a google search on line and found some Eastern B-pipes that were bolt in replacements. The only reason I replaced the cats was because the 3 way cats in the headers failed on a trip last year. The material literally broke up, went down the exhaust and plugged the secondary cat in the B pipe on the passenger side. This happened while I was pulling a 7000 pound trailer from Yellowstone back down to Texas, going over some very challenging grades. It wasn't until I got home that I realized she'd been doing the work with one hand tied behind her back. Other than a slight lack of power, I noticed that I was having to downshift too much and my mileage sucked. But I'm amazed I was even able to get back home! I pulled the driver side and noticed the 3 way cat was in pieces, but nothing had made it down the exhaust yet. I gutted that side as well just so everything was balanced.

interesting mighty... i read both your posts.

although ill never be able to do any of that or want to, its just fascinating reading what you have done... excellent information...

I must give a lot of credit to scr38. He pointed me in the right direction and helped with some of the details!

It was a lot of work, but I'm glad I did it and would do it again. It makes a good vehicle even better!

I must give a lot of credit to scr38. He pointed me in the right direction and helped with some of the details!

It was a lot of work, but I'm glad I did it and would do it again. It makes a good vehicle even better!

Thanks for the detailed info...and I may take you up on the "would do it again" part when I replace mine. One side was done by dealer and I'm sure the other side is getting ready to give me issue. I like to be proactive on keeping my vehicles ready. And if I'm not proactive on my military vehicle (see avatar) really bad things tend to happen.

Again,,thanks :udaman: