Exhaust Manifold Replacement

[Labonte18]

Originally Posted by kwong7

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.

Well, this isn't necessarily a Nissan specific question. Just a general 'best practices' thought on whether to replace both manifolds on a V engine. We've kinda run it up into some specific recommendations and comments based on the vehicle it is.. But.. Originally at least.. It was just a generic question of "You have one cracked exhaust manifold, would you replace both and why?"

Originally Posted by easy62

That’s why you heat them Up with this.

https://youtu.be/YJElT9xK3bk

Yeah.. I've watched my guy do some of the things I've sent to him.. I'm still happy leaving it to him. I pulled a rattling cat off one of my old trucks a number of years back and busted the catalyst out of it and put it back on.. But, I wasn't pleased at doing that. Only reason I didn't send that to him to do was because I wouldn't ask him to do that due to the legalities.

[M3 Mitch]

Maybe the best way to find out if replacing both makes sense is to ask your guy the question - how much to replace one manifold, how much to just do both at the same time? If he basically says doing both at one time costs 2X what doing one costs, I would say he expects 2X the work and no real savings for doing both at once, except of course driving the truck to the shop and getting rides home and back to the shop when it's finished.



In some cases, an aftermarket "header" exhaust is actually more robust than the stock manifold. Buddy had an 80's Nissan truck, small truck, 4-cylinder engine, and of course in this case putting on a header was very easy compared to most V engines. But his manifold cracked, he put on a header, and was happy with that solution. Most FI engines will compensate the mixture for a header, compared to the old days of needing to rejet carburetors.

[Electrician4you]

Originally Posted by Labonte18

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..)

Be prepared for a 800-1200 labor only bill. Not counting the manifolds.
I spray all my manifolds and pipe flanges the night before with penetrating oil. Really helps a lot. I can tell you my manifokdscwere both cracked. The pass side a lot more than the driver side. The driver side had smaller cracks
If you look at the flange you’ll see there is a gap between the 3rd and 4th cylinder flange n the factory manifolds. Some of the aftermarket ones are a solid piece all the way through. They also have gusset tabs at every downturn that meets the main exhaust tube.
The reason I did it myself was the cost was simply ridiculous. It is easier on a lift. If your buddy is doing it on the ground it’s gonna be a weekend.

If you are planning on keeping the truck get actual shorty headers, and new cats.there is a guy called Cajun B-pipes who makes a kit. Has a programmer. From what I understand it really wakes up that 5.6

The dealer quoted
$1200 per side on the manifolds parts cost
$200 core charge each manifold with cats
$2400 labor rate

Local shop quoted
$1500 for parts
$1000 in labor

I ended up DIY. Took me about 9 hours total and that was because I went really slow and I retightebed the bolts cleaned crap and basically farted around a little.. I can probably knock one out now in about 6/7 hours at a comfortable normal working pace.
$1200 bucks was my cost for parts. I had to buy CARB manifolds/cats with EO numbers for smog, otherwise I would of gotten away with about 600 bucks.