3.8L JK Unlimited Exhuast Manifolds

RDahms1

RDahms1

New member
My 3.8L JK has developed a slight exhaust leak from cracked manifolds. I've read where its a common problem that Chrysler is not considering helping or resolving and I'm ok with that. But I was curious if anyone has replaced theirs with aftermarket headers and which ones you used? How do they perform and/or sound? thanks for your input in advance!
 
Mitrig

Mitrig

New member
RDahms1 said:
My 3.8L JK has developed a slight exhaust leak from cracked manifolds. I've read where its a common problem that Chrysler is not considering helping or resolving and I'm ok with that. But I was curious if anyone has replaced theirs with aftermarket headers and which ones you used? How do they perform and/or sound? thanks for your input in advance!
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Im personally running a full gibson set up on my 3.8 jku. i picked up a gibson manifold as well as a gibson exhaust and set it up on quick disconnect c clamp to have it drop from the bracket i made it right after the cat and the pipe drop down. the whole set up works amazing, sound wise it is very loud. i get a consistent rumble when at a standstill. once past 1500rpm you get a good resonation, at 2000-3000 i get a deeper almost srt8 w/straight pipes sound, and god forbid i go higher it becomes ridiculous. it is very loud, i can post a video of the sound and set up i have for you to compare, it isn't for everyone but it is very convent and you do notice a jump in you mpg due to the unrestricted flow and in my case shortening of the pipe. (y) i think the whole set up cost me about 300 to do properly though my muffler was custom made from a gibson i gutted and altered. then tossed into a stainless steel casing a haha. got scared when i had to get it e tested in fear it would fail.
 
RDahms1

RDahms1

New member
Thanks for the input Mitrig. I was thinking just manifolds right now. Would the Gibson manifolds line up with factory exhaust?

Thanks Moochie. I've only got 78,000 on mine. I know the manager at the Jeep dealership but he said that Chrysler does not warranty exhaust manifolds up to 80,000, only cats and ECMs. It sucks, but I think I'd be happier with something that flowed better than stock.

Thanks again!
 
Tranquillity

Tranquillity

New member
I'd like to hear about headers as well, I suspect mine will crack too and headers looks like a good replacement. Heard a guy made 60 miles per gas tank. I highly doubt that but hope it's true deep inside :icon_crazy:
 
Moochie

Moochie

Active Member
I think they do have to replace your manifold. It is considered to be a part of your emissions control system.
ImageUploadedByWAYALIFE1382649824.928636.jpg
 
mcpuck

mcpuck

Caught the Bug
After Chrysler voided my factory warranty (for mods) my manifold developed the same leak. (I think they all develop leaks) I called Chrysler Customer Care and they paid for the parts and I paid labor. It cut the price in half. They know there is a problem so they don't argue about it.
 
TheDuff

TheDuff

New member
I have an evap leak and a small exhaust leak now, hope the dealer doesn't try to bend me over, I stupidly paid for the 100k warranty:(

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Spartan

Spartan

New member
TheDuff said:
I have an evap leak and a small exhaust leak now, hope the dealer doesn't try to bend me over, I stupidly paid for the 100k warranty:(

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Just a question since you got the extended warranty. Would you have spent a little more for a warranty that said warranty can't be voided due do mods. Would you still get it if some mods like lifts had to be done by the dealership, or a certified local shop?
 
TheDuff

TheDuff

New member
Spartan said:
Just a question since you got the extended warranty. Would you have spent a little more for a warranty that said warranty can't be voided due do mods. Would you still get it if some mods like lifts had to be done by the dealership, or a certified local shop?
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No, I would have rather kept the money in a account for repairs. I like to install my mods myself when I can and would never consider paying the dealer or a shop. They tried to sell me on a lift, but I'm honestly not interested in the lift options they offer. On top of that I already know, regardless of mods they will point out the scrapes, dings, and dents on my frame and skids... that's enough for them to claim offroad abuse and void it.
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Bigfoot

Bigfoot

Member
I have a cracked manifold, too. Since this seems to happen due to a design flaw in the OEM manifolds I am planning to replace them with a Gibson GP403S-C. Gibson's GP403 headers are available in three different versions: stainless steel, chrome coated or ceramic coated. I have decided to go with the ceramic coated version as the ceramic coating is supposed to reduce under hood temps and prevent melted spark plug cables.

Ceramic coating is more expensive but it is important to understand that the OEM manifolds do not get as hot as a stainless steel aftermarket header. Moreover most aftermarket headers will render the factory heat shields incompatible so that the spark plug cables will get exposed directly to the heat of the new stainless steel headers. If you do some research you will find that many users have had their problems with stainless steel headers in that regard.

If you want to improve the performance of the 3.8L as well you may want look at the RIPP long tube headers. They are very expensive though.

Of course you can choose whichever headers you like and have them ceramic coated yourself. This will give you more options.
 
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Mitrig

Mitrig

New member
RDahms1 said:
Thanks for the input Mitrig. I was thinking just manifolds right now. Would the Gibson manifolds line up with factory exhaust?

Thanks Moochie. I've only got 78,000 on mine. I know the manager at the Jeep dealership but he said that Chrysler does not warranty exhaust manifolds up to 80,000, only cats and ECMs. It sucks, but I think I'd be happier with something that flowed better than stock.

Thanks again!
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I personally went with the ceramic headers it only needed a slight modification intern of the heat sheild so I just altered it and made a new one. I used the majority of the same piping between the headers and muffler no modification was needed really. They make the majority of this stuff plug and play
 
H8MUD

H8MUD

New member
Subscribed. I'm also looking to replace my manifolds w/headers. My passenger side manifold is cracked.
 
RDahms1

RDahms1

New member
Thanks for the input Bigfoot! I never thought about the under hood temps being a concern. But I guess out on the highway or on the trail, it might be a good thing to think about. I was thinking Gibson or Rugged Ridge manifolds but wasnt sure what others were running or thinking about running.
 
Mitrig

Mitrig

New member
RDahms1 said:
Thanks for the input Bigfoot! I never thought about the under hood temps being a concern. But I guess out on the highway or on the trail, it might be a good thing to think about. I was thinking Gibson or Rugged Ridge manifolds but wasnt sure what others were running or thinking about running.
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Gibson is always a safe bet in my opinion. And for heat disputation you can always just makes heat sheild. You could always go back to oem manifolds since they are a bit cheaper. Could work well for you if you know anyone doing a 3.8 motor away just pick one off theirs abab
 
fishoutofwater

fishoutofwater

New member
I was just informed that both of my manifolds are cracked when I took it into the dealer to get checked out for excessive noise. Ironically they will replace the catalytic converter that was also bad for free but they won't replace the manifolds. They want to charge $690 a piece. I got to be able to get an aftermarket that performs way better for that price. Going to check into the Gibson ones. Any other recommendations are welcomed.
 
Moochie

Moochie

Active Member
fishoutofwater said:
I was just informed that both of my manifolds are cracked when I took it into the dealer to get checked out for excessive noise. Ironically they will replace the catalytic converter that was also bad for free but they won't replace the manifolds. They want to charge $690 a piece. I got to be able to get an aftermarket that performs way better for that price. Going to check into the Gibson ones. Any other recommendations are welcomed.
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How many miles on your Jeep?
 
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