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Never ending exhaust leak

17K views 42 replies 12 participants last post by  HRTKD 
#1 ·
Hey guys, I'm getting fed up with this thing. So when i bought this truck, it barely managed to get 9mpg, the exhaust was completely hacked to sh*t (see here: Code P1283.) So I set out to get the exhaust fixed, and get rid of any leaks. So i bought some JBA LT's from Cajun, Uprev from Joe, stock catted b-pipes, and the stock catback. Installed it all with OEM Nissan gaskets, and torqued everything to spec.

I fire it up, and it was better, but still had leaks, So Jeff told me to loosen everything up, and told me the sequence best to torque it all back down with. So i did, and it got better. You couldn't hear it at idle any more, but you could here it while driving or under load.

So Jeff recommended that the stock b-pipe flanges might be warped, as they are thin and are prone to warping when you torque them down. So i bought the 2.5" cajun catless b-pipes.

Been a few weeks now, and I swear i can still hear it. Now i do have a hearing problem, so its hard to be 100%. It might be injector ticks, header pings, or an exhaust leak. All i know is that since it has the stock muffler, its very quiet and i can here everything that comes from the motor.

I cant figure out how to make it stop. Whatever the sound may be, it makes me cringe every time i drive it. Im so close to pulling it all out and using high temp RTV on the entire system with no gaskets. Also debating on selling it and letting it be someone elses problem.

Any other ideas guys?
 
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#2 ·
see if your mpg has gotten better? get a louder muffler hahah wont hear it anymore
 
#3 ·
Is there any kind of spray to spray on to detect any leaks?
 
#4 · (Edited)
My MPG has gotten better, but is still sub-par. Just did a 250 mile trip this weekend and only got 11.9mpg with the cruise set at 67mph with no hills. My 08 wouldve done the same trip with 17-18mpg, i just needed 4wd once i got there.

I've heard of people using smoke machines to check for leaks, but i dont have one or have access to one.
 
#15 ·
Mechanic's stethoscope is cheap at Harbor freight tools.
 
#6 ·
I'm dealing with leaks also. The shop I take the two other family cars to has a smoke machine and they used it to find a number of leaks in my Titan. My Berk Technologies b-pipe flanges aren't fulling seating against the JBA LT header flanges. They used a couple gaskets and some gasket RTV there. But not all the leaks are gone as my CEL is back after about 200 miles. If I hammer the accelerator that seems to be key to getting the CEL to come back on. I'm wondering if I blew out the RTV.
 
#7 ·
I havent had any Check engine light since i got the new b-pipes, so thats a good sign for me.

I think im going to try and rule out injector ticks first, so i ordered 25' of 4 ga wire and a pack of ring terminals, going to make a grounding kit and see if it helps at all.
 
#17 ·
The injectors on these trucks are notoriously loud but headers do sound different than manifolds and my truck has noticable header ping. Just had to get use to that but every truck i have owned has had headers on it.

Jumping from 9mpg to 12mpg is a good jump especially with larger tires and a lift. My mpg dropped 1.5mpg changing from stock size street tires to stock size Bridgestone AT's.
 
#8 ·
I have a grounding kit in mine already. I have ticks, but not enough to bother me.
 
#10 ·
Sell it and buy mine.



I've got cracked oem manifolds. Super leaky
 
#11 ·
Wait, you have 10" of lift on your '05 and you're getting 12MPG? Isn't that good for that amount of lift?

If you're not throwing a code I think it's just in your head. Mine kept throwing a CEL and I couldn't find it. Removed/tightened down headers 3-4 times, re-torqued everything, double gaskets on the b-pipes. Joe told me it wasn't serious enough to affect anything and my mpg/power hasn't suffered so I just turned the code off.
 
#12 ·
Yeah I agree. I'm only leveled with 33's and I average 12mpg lol
 
#13 ·
i am with honda on this i have 34's with 2.5" lift i get 12mpg if im driving like my grandma.
you should feel blessed to get 11.9mpg with that lift..
 
#14 ·
Thats all highway as well guys, in the city (which is all i drive to work) im lucky to get more than 200 miles to a tank. I dont think thats normal when my last 05 on 37's got a consistent 13mpg, freeway or city.

But, you guys could be completely right, It could be all in my head. I might just be hearing a combination of header ping, injector tick, and the intake noise and overreacting. I think ill start with the grounding kit and try and cure the injector tick, then if i can still hear it, a louder exhaust it is.
 
#16 ·
If you have a shop vac reverse the flow into blower mode and duct tape the hose to the tailpipe. Get a spray bottle with warm soapy water and start spraying the connections in front of the bpipe sensor and look for bubbles. That is the best way to find leaks on this exhaust system without paying someone to do it. A leak in front of the bpipe sensor will throw a code, anything behind that sensor is not a cel issue.

Unfortunately Nissan provided us with 2 bolt flanges on these trucks and SUV's which are sub-par IMO. Cajun has the best possible flanges available and if installed properly should not leak with nissan gaskets. If a Cajun flange is warpped or a weld is leaking or cracked ship it back to me and i will fix it.
 
#18 ·
Jeff is so right here, I did the shop vac test and found about 5-6 leaks. On each side of the muffler
at the resonator, and the worst place at the bung on bank one o2 Sensor. So I gooped everything up
including the outside threads of the o2 sensor. It only throws that ghost code now on long trips on the interstate cruising around 75mph. Around town it doesn't throw the code. so I've come to the realization that twice a month I do the ECU reset procedure, got it memorized and the truck runs great.
I've got 164K miles on her and she runs great. Eventually I might replace that one Bpipe and bung but
it's just not that big of a deal anymore. Spent 2 years chasing that code and a ECU reset that takes one minute to turn off the CEL is no big deal...
 
#19 ·
I do have a shop Vac, I'll try that this weekend, thanks Jeff!

Yeah 9 to 12mpg is a pretty big jump, especially with heavy (cheap), 35" MT's. But i plan on trying to squeeze a little more out of her. Going back to 3.36 gears in the rear so my gearing matches and get my 4wd back, and maybe pick up some hwy mpg. And then also with the JBA catback to try and free up the exhaust a little more.

Ill keep you guys posted with my findings.
 
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#20 ·
Now im sure you have had this question asked before Jeff, but would it be worth it to cut off the 2 bolt flanges and weld in the 3 bolt flanges with new gaskets? Sounds like an easy deal to me.
 
#21 ·
If i did anything i would Vband the header and bpipe but three are hundreds of guys out there that are leak free. I bet you can eliminate the leaks with some trial and error. If your ever through my area get with me and we can stop it. My truck is leak free and has been since day 1 77K miles ago and 4.5 years.
 
#22 ·
OEM Muffler could be bad and causing back pressure. I had an all stock system and power was reduced. Couldn't figure it out for ever. Then the muffler started to rattle at idle. I bought a Black Widow muffler from A.I.I. Racing off here. After I replaced the muffler, started it up, backed out of the driveway, put it in drive and punched it I swear the front end came up (of course that's an exaggeration) but it was like a night and day difference. Just a thought.
 
#27 ·
Header to bpipe is the only one that will trip a code, anything behind the rear sensor will not throw a code. Try doubling the Nissan gaskets at the header to bpipe and see what happens.
 
#26 · (Edited)
I worked on my exhaust leak today. Whatever fix my mechanic did had undone itself this week. The leak was so bad that it was embarrassing. My Titan sounded like a beater truck.

I loosened all eight nuts on the passenger header and used a floor jack to raise it up by the flange. After tightening all the nuts I measured the difference at the flange and it looks like I brought it up about 3/16". That may help the gap at the flange and it should also help ensure the header clears the engine mounts. This is something that I should have done during the initial install. Live and learn.

I then installed two Fel-Pro gaskets between the header flange and the b-pipe flange. After starting it up and letting it run for 30 seconds I noticed that it cleared the check engine light on its own. I'm taking that as a good sign but I'll keep my fingers crossed.
 
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#31 ·
LT headers plus a tune plus new b-pipes is $1,000+ more than the Dorman solution. He's not looking for performance, just a fix for leaking OEM manifolds.
 
#33 ·
Got a post I can point my buddy to? Personally, I think any offering from Dorman is crap. I speak from experience.
 
#35 ·
I had a guy who was a member on here ,cant remember his name but he made several post on the $900 each magnaflows that failed at 6 months. Ended up with a huge labor bill and gutting the magnaflow manifolds and getting Uprev and a set of catted Cajuns to pass Austin Tx emissions. If he would have went with Lt's in the first place he would have saved about $2000. The Dormans fail horribly in no time is what im being told by customers who call me. The JBA shorty route with welded cats is no better.
 
#37 ·
Update: The vibration was most likely a front wheel bearing going bad. Replaced both this weekend.

Today I put in an OEM cat-back exhaust from a donor Titan just in case the Magnaflow 22" muffler had a blockage. It sounded horrible so I think there was something wrong in there.

I found one of the heat shields attached to the underside touching the passenger side O2 sensor on the b-pipe. Is it possible that contact like that could cause the sensor to be faulty"



My buddy's Dorman exhaust manifolds came in. Good grief those things look horrible. The outside is so nasty looking that at first I thought they were used.
 
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#36 ·
Update on my "fix".
Sunday: Did the fix detailed a few posts up. Check engine light cleared itself, possibly because I disconnected the battery for three hours.
Monday: Made it 50 miles and the check engine light came back on. Heavy traffic. When I got home I inspected the exhaust and didn't see any obvious issues. Reset the check engine light.
Tuesday: Made the round trip work commute (~72 miles) and the check engine light stayed off. Easy traffic.

I now have a vibration that appears to be RPM related. I looked over the exhaust and can't find anywhere that the pipes are hitting anything. The engine mount bolts look tight. No idea where the vibration is coming from. It started Monday after I did my "fix".

The Remflex gasket material arrived today. Wow, this stuff is much thicker than I expected. It has to be the thickness of at least three OEM gaskets. Plus, it compresses. If my flange leak becomes a problem I'm going to give the Remflex a try. The downside is you have to cut your own gasket from the sheet of material.
 
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#38 ·
I sure hate to see him waste his time with those things. Live and learn I guess.

The Magnaflow muffler is packed with fiberglass, even though it sounds great the Maggy last about 3 years or so before the packing breaks down. This is why I like JBA and Borla as these muffler last forever. Keep us posted on the gasket deal....
 
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