3.6 JK exhaust manifold crack?
#1
JK Freak
Thread Starter
3.6 JK exhaust manifold crack?
I can’t find any exhaust manifolds for a 3.6 V6. Called the dealership parts department, but they couldn’t find anything either.
I recently crushed the exhaust crossover on a rock. It bent the bolts for the exhaust spacer on the passenger side, and was completely open. Jeep threw a code for the 02 sensor and it smelled like a boat. I went in today to have the trail patch (flex tube) replaced with a bent piece. After the guy finished, he said I cracked the manifold on the driver side. I believe him, I can still smell a leak somewhere, and can hear a whistling when I’m in 1st, 2nd, or 3rd gear and decelerating. Whistling goes away if I’m coasting in neutral, the second I depress the clutch, or if I upshift to way too high of a gear (5th gear at 35mph).
Anyone have any comments or experience? I took a look under the Jeep and could only trace the exhaust back to the cats. Almost looks like it bolts straight into the engine block. I couldn’t see any cracks, but I also have no idea what I’m looking at.
This is what I had done (yeah I really need to get off my butt and bolt my oil pan skid on ):
I recently crushed the exhaust crossover on a rock. It bent the bolts for the exhaust spacer on the passenger side, and was completely open. Jeep threw a code for the 02 sensor and it smelled like a boat. I went in today to have the trail patch (flex tube) replaced with a bent piece. After the guy finished, he said I cracked the manifold on the driver side. I believe him, I can still smell a leak somewhere, and can hear a whistling when I’m in 1st, 2nd, or 3rd gear and decelerating. Whistling goes away if I’m coasting in neutral, the second I depress the clutch, or if I upshift to way too high of a gear (5th gear at 35mph).
Anyone have any comments or experience? I took a look under the Jeep and could only trace the exhaust back to the cats. Almost looks like it bolts straight into the engine block. I couldn’t see any cracks, but I also have no idea what I’m looking at.
This is what I had done (yeah I really need to get off my butt and bolt my oil pan skid on ):
Last edited by BoraBora; 07-03-2018 at 10:45 AM.
#3
JK Freak
Thread Starter
#4
JK Freak
Thread Starter
Well I guess a little update here, and also thinking out loud:
Spent some time trying to find someone else who did this, and this thread sounds exactly like my issue (excuse the website): https://wayalife.com/showthread.php/...k-on-pentastar
Since there are no cracks at the heads, I'm thinking I can go to the dealer and tell them I have bad cats. Luckily cats are covered for 8 years/80,000 miles under Federal Emissions Warranty. Manifolds are only for 24,000 miles/2 years. Thinking I mention nothing of trail damage, spend some time cleaning the undercarriage before going in, and say I was getting "custom exhaust work done to delete the cruddy exhaust spacers" when they noticed a leak where the cats bolt up to the "manifold" (head).
Feel free to voice any comments. Trying to go wheeling in 2 weeks, so hoping to knock this out before then.
Spent some time trying to find someone else who did this, and this thread sounds exactly like my issue (excuse the website): https://wayalife.com/showthread.php/...k-on-pentastar
Since there are no cracks at the heads, I'm thinking I can go to the dealer and tell them I have bad cats. Luckily cats are covered for 8 years/80,000 miles under Federal Emissions Warranty. Manifolds are only for 24,000 miles/2 years. Thinking I mention nothing of trail damage, spend some time cleaning the undercarriage before going in, and say I was getting "custom exhaust work done to delete the cruddy exhaust spacers" when they noticed a leak where the cats bolt up to the "manifold" (head).
Feel free to voice any comments. Trying to go wheeling in 2 weeks, so hoping to knock this out before then.
#5
AFE makes two pipes that I think every 3.6 should have installed. One is a pipe that relocates the crossover pipe behind the cross member and the other is a loop delete (straight pipe). Much better and out of the way. Sorry, I can't offer any input on the cats.
#6
JK Jedi
y, only have the one pic to go off of, but was going to ask why not just totally reroute the exhaust if you were going in to a shop anyhow? Can't recall if the 2dr crossover runs much differently than the 4dr, but I would have routed it away from that front DS (and in front of the cross member) if I was paying someone anyhow. Realize you're not asking about that at all....was just curious.
#7
JK Freak
Thread Starter
y, only have the one pic to go off of, but was going to ask why not just totally reroute the exhaust if you were going in to a shop anyhow? Can't recall if the 2dr crossover runs much differently than the 4dr, but I would have routed it away from that front DS (and in front of the cross member) if I was paying someone anyhow. Realize you're not asking about that at all....was just curious.
Why they put it on the autos and skipped the manuals...I have no idea. I'll be fabbing up some sort of skid to protect the crossover soon. Just need to drop my gas tank skid, flatten it with a BFH, install a 3/16" skid, and bolt my oil pan skid on first. My undercarriage is begging for attention.
Last edited by BoraBora; 07-04-2018 at 07:33 AM.
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#8
JK Jedi
I found a steal of a deal on a barely used AFE y-pipe years ago, so re-rerouted the exhaust behind the cross member. Had a couple buddies have mom 'n pop muffler shops do the same thing for ~$50-70. I mainly did it to free up DS clearance. Coarse, the issue with re-routing like that is you get close to that gas tank corner, and have to be comfortable doing that.....heat shield over all the fuel lines and corner of gas tank. Yup, time for some sort of oil/tranny skid which would cover all that up. surprised your cross member doesn't look bad at all. My factory looks terrible, but it's a common place to hit on 4dr.
#9
JK Super Freak
Originally Posted by T&ERun
AFE makes two pipes that I think every 3.6 should have installed. One is a pipe that relocates the crossover pipe behind the cross member and the other is a loop delete (straight pipe). Much better and out of the way. Sorry, I can't offer any input on the cats.
Originally Posted by BoraBora
Can't find any for 2 doors. Looks like they only offer the loop delete for us.I didn't have very many options without doing a full on custom exhaust ($$$ vs. $). I also didn't want to mess with the loop on the drivers side; I've heard nightmares of people removing it and noticing a loss in performance. Absolutely stupid design, but I'm working around what's already there. Looks like autos have better protection for the crossover pipe. They have this secondary bar that bolts onto the crossmember and kind of protects it from what happened to mine:
Why they put it on the autos and skipped the manuals...I have no idea. I'll be fabbing up some sort of skid to protect the crossover soon. Just need to drop my gas tank skid, flatten it with a BFH, install a 3/16" skid, and bolt my oil pan skid on first. My undercarriage is begging for attention.
Why they put it on the autos and skipped the manuals...I have no idea. I'll be fabbing up some sort of skid to protect the crossover soon. Just need to drop my gas tank skid, flatten it with a BFH, install a 3/16" skid, and bolt my oil pan skid on first. My undercarriage is begging for attention.
Magnaflow also makes one, and they list the same part number for either 2 door or 4 door. Also, it doesn't appear that Mangaflow includes any heat shielding for the fuel lines and fuel tank. At least not shown on their website.
Also, that extra crossover is pointless. It is super soft steel. Everyone I have seen on a Jeep that gets wheeled ends up crumpled up like an old napkin the first time it brushes a rock. Pretty sure it is just a feel good part they put on hoping people won't play in the rocks.
Last edited by tjkamp; 07-04-2018 at 05:52 PM.
#10
JK Jedi
the metal gaskets between the heads and the cats will warp when you hit that cross pipe hard enough. i was with my buddy when he did exactly that. all of the sudden got the wfft wfftt wfft sound and threw a code. Stupid design and not an easy place to get to to change the gaskets.