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Old Yesterday, 05:22 PM
 
8,768 posts, read 6,462,229 times
Reputation: 11300

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So.. Exhaust is one thing that I never touch, for one simple reason.. You wind up in a quagmire. Rusted bolts, bolts that snap off.. If I have an exhaust problem, I've got a guy for that. Let him have the headaches, not me.

But, I've got someone who has been asking me for help with an exhaust leak.. I agreed to test it out for him to see if we could identify where the leak is happening. Doesn't sound horrible, but even my deaf-ass can pick up that.. There's a leak in the exhaust somewhere. Not large.. I'm expecting to find a crack in a manifold. (This is an '05 Nissan Titan FWIW.. Which is why I say I expect to find a crack in the manifold)

Told him that.. Hey.. There's a chance that some of the high temp JB Weld, pending on the size of the crack and where it's located, might work. I've heard some people swear by it. So long as we're not sticking it on a bolt or something.. Worth a shot.

But.. It got me thinking.. with the newer exhaust manifolds usually having an attached cat on them.. if you found that you had a drivers side exhaust manifold cracked (assuming V-6 or V8 here, of course) but the passenger side appeared to be fine..

Would you replace both or just the cracked one? Would mileage make a difference to you?

I've ALWAYS been of the opinion to do as much as you can when you're in there, however.. I don't particularly see an advantage on the exhaust. Two completely different sides of the engine.. While you still have the theory that if one went, the other isn't far behind.. You're not saving any real money by doing both at the same time. You've got one set of parts that have to come off to get to one, another set to get to the other. The only time you're saving is a return visit to the shop.

The exhaust manifolds for this thing are about $220 per side. so, add in the extra labor, it's a decently significant cost (especially for him) if both sides were to be done. i'm just looking for.. Is there something I'm not considering here that blows my idea of only replacing one side out of the water?
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Old Yesterday, 07:07 PM
 
Location: Texas
5,606 posts, read 12,358,942 times
Reputation: 10619
The Titan for YM 2005 was plagued with faulty exhaust manifolds. Many were expecting a recall but it never happened. Nissan did extend the warranty to 8 years or 100,000 miles, whoopy-doo! Frankly, I'd JB Weld the thing in place and find the truck a new owner. Most likely, you'll find the cat behind that side is toast as well. I doubt it would pass any kind of exhaust emissions now. Cats don't function long when there is oxygen in the exhaust stream that allows temps to soar well beyond the scopes of operational temps. So much for japanese quality. Biggest problem now would be finding someone stupid enough to give anything more than pocket change for it. But best of luck with it anyway. The JB weld should get you back to quiet.
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Old Yesterday, 10:14 PM
 
1,325 posts, read 1,475,442 times
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I would possibly try the JB Weld exhaust manifold crack repair with a low expectation that it will work. With the pressure of the exhaust and the heat, I would bet it will not work, or even last very long, if it does.



I would only replace the manifold for the leak side and would leave the other side alone if it is not leaking. It may never leak.
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Old Yesterday, 10:23 PM
 
Location: in the soup
3,582 posts, read 1,494,646 times
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I didn't know JB weld made something to hold up to exhaust heat. Seems unlikely that it'd work for long. But I didn't know that existed until now... so what do I know?

As for whether I'd repair one side or both on a V engine... that just depends on the situation. If the second manifold isn't too hard to get to and/or if it's obvious that a repair will be needed soon, I'd probably go ahead and do it. If it's going to be a real pain to get to and/or there are no signs of imminent failure, I'd just fix what's broke.

Regardless, it needs to go back together with antiseize on every thread. That will make the repair much easier next time.
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Old Yesterday, 10:30 PM
 
8,768 posts, read 6,462,229 times
Reputation: 11300
Quote:
Originally Posted by turkey-head View Post
I didn't know JB weld made something to hold up to exhaust heat. Seems unlikely that it'd work for long. But I didn't know that existed until now... so what do I know?

As for whether I'd repair one side or both on a V engine... that just depends on the situation. If the second manifold isn't too hard to get to and/or if it's obvious that a repair will be needed soon, I'd probably go ahead and do it. If it's going to be a real pain to get to and/or there are no signs of imminent failure, I'd just fix what's broke.

Regardless, it needs to go back together with antiseize on every thread. That will make the repair much easier next time.

Engine has 250k on it.. I don't personally think there'll be a next time.

There are several 2400 degree rated epoxies out there that CLAIM to be able to seal up small cracks in exhaust. And of course the tapes for holes.. I've never used any of them, so I can't speak to how well they work, but.. I have heard tell that they do pretty decent.

This guy doesn't have the money to replace the manifolds.. So, I'm hoping we dig in and find just one side is blown and maybe the patch stuff will hold up for a year or so. But.. If it were my vehicle, I'd have both manifolds replaced most likely, but.. as I said, there's reasons that won't happen, so.. Didn't know if doing only one side was problematic in any way. I couldn't think of how it would be, but.. Easier to ask than screw it up and try to fix it.
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Old Yesterday, 10:33 PM
 
17,213 posts, read 18,609,416 times
Reputation: 24994
Quote:
Originally Posted by Labonte18 View Post
So.. Exhaust is one thing that I never touch, for one simple reason.. You wind up in a quagmire. Rusted bolts, bolts that snap off.. If I have an exhaust problem, I've got a guy for that. Let him have the headaches, not me.

But, I've got someone who has been asking me for help with an exhaust leak.. I agreed to test it out for him to see if we could identify where the leak is happening. Doesn't sound horrible, but even my deaf-ass can pick up that.. There's a leak in the exhaust somewhere. Not large.. I'm expecting to find a crack in a manifold. (This is an '05 Nissan Titan FWIW.. Which is why I say I expect to find a crack in the manifold)

Told him that.. Hey.. There's a chance that some of the high temp JB Weld, pending on the size of the crack and where it's located, might work. I've heard some people swear by it. So long as we're not sticking it on a bolt or something.. Worth a shot.

But.. It got me thinking.. with the newer exhaust manifolds usually having an attached cat on them.. if you found that you had a drivers side exhaust manifold cracked (assuming V-6 or V8 here, of course) but the passenger side appeared to be fine..

Would you replace both or just the cracked one? Would mileage make a difference to you?

I've ALWAYS been of the opinion to do as much as you can when you're in there, however.. I don't particularly see an advantage on the exhaust. Two completely different sides of the engine.. While you still have the theory that if one went, the other isn't far behind.. You're not saving any real money by doing both at the same time. You've got one set of parts that have to come off to get to one, another set to get to the other. The only time you're saving is a return visit to the shop.

The exhaust manifolds for this thing are about $220 per side. so, add in the extra labor, it's a decently significant cost (especially for him) if both sides were to be done. i'm just looking for.. Is there something I'm not considering here that blows my idea of only replacing one side out of the water?
Nothing short of removing welding bracing reinstalling or buying new ones will fix the issue. The VK56/5.6 V8 is KNOWN for cracked manifolds. Usually the break is because there is no support between the last two cylinders on the header flange. The aftermarket usually has a car he piece flange and gusseted corners where the tubes meet to form the main exhaust “log”

Usually the passenger side cracks more than the driver side. The driver side cracks too. You don’t wanna drive a long time like that.

I can tell you that I just did the exhaust manifold swap n my wife’s QX56 which is basically the SUV version. It took about 6 hours one day and a two hour span the second day. I had the use of a lift. If you’re doing this on the ground.....good luck. I wasn’t going fast, I could of done it all in one day.
You’ll need to remove the wheels and the inner fender liners

You’ll NEED to loosen (ONLY LOOSEN) the motor mount to block bolts enough to lift the engine up about 1 inch. You CANNOT get the manifolds out otherwise,
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Old Today, 09:41 AM
 
8,768 posts, read 6,462,229 times
Reputation: 11300
Quote:
Originally Posted by Electrician4you View Post
Nothing short of removing welding bracing reinstalling or buying new ones will fix the issue. The VK56/5.6 V8 is KNOWN for cracked manifolds. Usually the break is because there is no support between the last two cylinders on the header flange. The aftermarket usually has a car he piece flange and gusseted corners where the tubes meet to form the main exhaust “log”

Usually the passenger side cracks more than the driver side. The driver side cracks too. You don’t wanna drive a long time like that.

I can tell you that I just did the exhaust manifold swap n my wife’s QX56 which is basically the SUV version. It took about 6 hours one day and a two hour span the second day. I had the use of a lift. If you’re doing this on the ground.....good luck. I wasn’t going fast, I could of done it all in one day.
You’ll need to remove the wheels and the inner fender liners

You’ll NEED to loosen (ONLY LOOSEN) the motor mount to block bolts enough to lift the engine up about 1 inch. You CANNOT get the manifolds out otherwise,

Trust me.. I'm not doing it. I'm not pulling the manifolds. If it comes to that.. It goes to my guy.

I did an exhaust manifold on one of the old Ford Escorts back in the day. Talking the 80's Escorts.. You know, sideways engine so the exhaust manifold is right there in front of you, easy as can be? Yeah.. Took me 3 days to get that thing put back together after all the stuck and broken studs and the like. I swore off exhaust at that point. (And just swore in general as well, but..)
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Old Today, 12:14 PM
 
2,629 posts, read 3,168,886 times
Reputation: 5096
It is a Nissan so yes it is most likely a crack in the exhaust manifold. Nissans have been notorious for cracking exhaust manifolds since the 80's and they still are today. Obviously Nissan doesn't give a rip and try to make them just good enough to get through the warranty. Forty years of cracking manifolds is more than enough time to get feedback and know you need to improve their reliability and design.

Anyway, this is one of those if it isn't broke don't fix it sort of things. Replace the cracked one and leave the other one alone until it decides to crack. They are on opposite sides and so you would have to specifically do the work just to remove the other side so there is no benefit in going through the trouble now if it isn't cracked.
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Old Today, 12:45 PM
 
1,030 posts, read 976,649 times
Reputation: 1273
Default Obligatory



In all seriousness, I would think searching through a Nissan Titan specific forum might give you the best advice as I'm sure you'll find hundreds of fellow owners who have tackled this issue in a number of different ways. I know some vehicles were prone to leak at the flex section, but an actual crack to the manifold seems like a bad design, cheap production, or insufficient tolerances from the rubber bushings/hangers for the exhaust system.
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Old Today, 01:03 PM
 
Location: Metro Detroit Michigan
3,526 posts, read 960,781 times
Reputation: 2842
Quote:
Originally Posted by Labonte18 View Post
Trust me.. I'm not doing it. I'm not pulling the manifolds. If it comes to that.. It goes to my guy.

I did an exhaust manifold on one of the old Ford Escorts back in the day. Talking the 80's Escorts.. You know, sideways engine so the exhaust manifold is right there in front of you, easy as can be? Yeah.. Took me 3 days to get that thing put back together after all the stuck and broken studs and the like. I swore off exhaust at that point. (And just swore in general as well, but..)
That’s why you heat them Up with this.

https://youtu.be/YJElT9xK3bk
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