2003 Exhaust manifold

So My 2nd manifold has crapped out, Having a good dealership is worth soo much. I talked to them and asked if they could replace the 2001 Manifold with the stronger and re-designed 2003. as I write this my truck is on the hoist, they are not sure it will fit but will do it at no extra charge if they can get it in. A fellow PNWX'er suggested it would ad about 5-10 hp to the truck to wich the dealership seems to agree...

Stay tuned.

Claus

Please get part numbers for old and new.

Thanks,
Brent

Mine is done today!! Talking with the service rep, he said all manifolds are supposed to be replaced with the most recent one, so theoretically you wouldn't need to ask, but I checked with them twice to make sure.

BTW, good thing it was under warranty, they said mine was a pain in the ass to get off.

Originally posted by OffroadX
Please get part numbers for old and new.

Thanks,
Brent

Not so!. I asked why they just did not scrap the old ones and used the 2003. I was advised that they have different part numbers for the different year models.

I have a vioce mail into the dealership trying to get the part number as it did not appear on my invoice.

Nice dealership, they rotated my tires and tightened the handbrake at no charge.

:bigthumb:

Well I guess the moral of the story is to ask before they do it. I got a different story in that the service updates include the latest parts Nissan advises.

So more HP eh? It will be interesting to hear my truck. I think that manifold has been broken half the truck's life.

You said Eh,

Might just be me but I seem to feel it being a bit more "lively"

They also recommended a "level5" serivce on the truck. I asked what that was adn was told the following:

1. Rotate tires Whoohooo
2. Change Oil and Filter Whohooo
3. Inspect Brakes double Whohoo
4. Change all fluids Whohooo
5. Measure exhaust levels (just had it Aircared for $48)
6. test allignment...again Whohoo
7. new sparkplugs

I was advised this service comes to $600 canadian including parts....WTF do I have SUCKER written on the back of my shirt. I told him that I would do 98% of it myself where after he looked like a schoolkid caught cheating

Plugs are good for 100k miles.

As you already know, fluids we do with the club GL4 oil, and repack our own bearings.

I had them check out the brakes, just because they've been acting weird lately.

New belts because I don't want to mess with that, and I think Carlton's message about replacing belts was a good reminder after he lost one in Moab.

The one that cracked me up was replace radiator cap at 60k miles (my dealer didn't suggest it, but it's listed). Wow, I sure need a service department for that. :bloated:

What's sad is that a disreputable service department can really rip off an unsuspecting customer if they want.

Don't mean to be the bearer of bad news, but nobody is going to get 5-10 HP off one factory manifold unless yours was plugged up. Your truck will sound better though; at least until the new one cracks.

My driver's side manifold is cracked now...hopefully i will be doing headers and high flow cats this fall.

Hey back off buddy! I've already got HP gains from the 2 stickers I put on my truck. :D

All I care about is that the damn thing doesn't crack. Or if it does, it happens befor my warranty is out.

Well I've got those nice big Calmini stickers and those are worth mucho power gains! :D

Just a thought.. but when my manifold starts leaking, I plan on going to the dealer here, who is very friendly, and getting the replacement manifold from them, get it ceramic coated inside and out, then take it back and have it put on. That should keep it from rusting out again.

Any thoughts why this wouldn't work?

Originally posted by Walrus
Just a thought.. but when my manifold starts leaking, I plan on going to the dealer here, who is very friendly, and getting the replacement manifold from them, get it ceramic coated inside and out, then take it back and have it put on. That should keep it from rusting out again.

Any thoughts why this wouldn't work?

as far as i know it has nothing to do with rust.

As Evergreen says, it's a design flaw that's existed since the creation of the engine, not a rust problem.

Originally posted by evergreen


as far as i know it has nothing to do with rust.

Yeah what he said

Yup, the newer one is supposed to be thicker/stronger. The underlying problem is the fact that the block and manifold heat at different rates and there is thermal expansion stress going on. Originally back in the VG30 days, the manifold would pull away from the block and break the studs. Nissan started putting in larger studs later on and the problem became cracked manifolds instead. Presumably the stronger manifold will do the trick, assuming the larger studs can handle the stress that it will put on them.

Brent

I had 2 broken studs in addition to the cracked manifold.

I had several broken studs also. (and then Nissan sent the wrong studs.) Was in the shop three days getting it all sorted out.

Toy Man

Are you sure they were broken before they started trying to remove the manifold? I've heard of studs breaking when a wrench is put on them, but I don't know that they've broken from stress.

Brent

Yes, some people have had broken studs. I think Andrea in PNWX had one or two broken studs too. I think what happens is the manifold not only cracks but also warps in some cases. The warping is what breaks the studs. I can't wait to see what mine look like when I finally get around to getting headers on.

Right, that was the original problem, warped manifolds pulling on the studs. Looks like they've come full circle.

I think what happens is the manifold not only cracks but also warps in some cases.

Strangely enough, I had the warping problem on my '86 Toyota-based RV. The 1-ton truck had 100K on it, and the exhaust manifold (4-cyl) warped. It was obvious with a long straightedge.

I'm the 2nd owner, and after talking with an (unrelated) engineer, he speculated that after years of heat-cycles, the manifold changes crystalline structure, allowing warpage. He also said it should habe stabilized, and I should no longer have a problem with it warping.

...OK...Sounds good to me... :bloated:

It only cost $35 to have the manifold surface-ground; I installed oversize studs at the same time...

No cracks...cross fingers... :rolleyes:

See, I got a totally different story from the mechanic at the dealership that does my work. I was told that the reason the bolts break is that the exhaust does not have enough play to move with the engine. As far as the manifold itself, yeah he said they all have that flaw.

But whats right about the bolts?

When I had my manifold changed they said that it sheared two of the studs in the block. That must've really sucked. Having to drill it out and tap them. Well, I guess it was easier to do since they had the cylinder head off to change the head gasket at the same time.

See, I got a totally different story from the mechanic at the dealership that does my work. I was told that the reason the bolts break is that the exhaust does not have enough play to move with the engine. As far as the manifold itself, yeah he said they all have that flaw.

But whats right about the bolts?

Most everything I've heard goes along with your mechanic's description. We have people in our club who have broken the same manifold in a matter of months, so it has nothing to do with breakdown of the metal but rather stress on it from the exhaust leveraging the manifold.

And Brent, mine had at least two sheared off bolts as well :(. The shop manager said it was a bitch to get the thing repaired.

I can't wait to see what mine look like when I finally get around to getting headers on.

ChuckH -

What headers are you looking to put on???

Well I've got those nice big Calmini stickers and those are worth mucho power gains! :D

That must be why you have 3 on your truck. Tripple HP :p

BTW thanks for the free delivery. :smile: