Exhaust manifold

[mcclueth000]

I'm new to the forum, but i like a lot of other people on here have not one, but two exhaust manifolds that craped out on me. All the stuff ive been reading on here has been from back in 2009. Has there been any progress twords an alternative to the OEM manifold, because I don't want to drop $1200+ on a part that has already failed once.

 

[stevec5000]

I'm new to the forum, but i like a lot of other people on here have not one, but two exhaust manifolds that craped out on me. All the stuff ive been reading on here has been from back in 2009. Has there been any progress twords an alternative to the OEM manifold, because I don't want to drop $1200+ on a part that has already failed once.

There are replacements on Amazon but how could a manifold possibly crap out?

 

[BlackWorksInc]

What engine are you running? When/where/how did the other 2 manifolds fail?

 

[mcclueth000]

Its just an exhaust leak in the manifold, and im running the 4.7L V8

 

[03_4x4Runner]

Although it never happened to me, there are a lot of threads about the V8 cracked manifolds. How many miles did you get before they cracked?

 

[mcclueth000]

I began to notice it at about 78K miles. Im now at about 82K and it has gotten progressively louder. Although after a few minutes of warming it up it gets quieter.

 

[03_4x4Runner]

Here is an old post. http://www.toyota-4runner.org/4th-gen-t4rs/115116-v8-aftermarket-exhaust-manifold.html

 

[djlandkpl]

It'll be closer to $3800 if you have a dealer do both sides. Painful.

 

[stevec5000]

I began to notice it at about 78K miles. Im now at about 82K and it has gotten progressively louder. Although after a few minutes of warming it up it gets quieter.

Are you sure it's cracked and not just warped? Cracks can be welded up and if it has a warped surface and is leaking around the gasket it can be ground down flat again to fix it. The manifold on my pickup with a 22R engine, which is cast iron, was getting louder and louder so I took it off one day and found it was warped and leaked around the exhaust gasket between the manifold and the head. I used a belt sander to grind it smooth and flat again, put it back together with a new gasket and now it's fine.

 

[mcclueth000]

It'll be closer to $3800 if you have a dealer do both sides. Painful.

Yeah that why ive been looking around for a possible performance replacement or anything other than OEM because i don't want to buy the same part that just stopped working properly.

 

[mcclueth000]

Are you sure it's cracked and not just warped? Cracks can be welded up and if it has a warped surface and is leaking around the gasket it can be ground down flat again to fix it. The manifold on my pickup with a 22R engine, which is cast iron, was getting louder and louder so I took it off one day and found it was warped and leaked around the exhaust gasket between the manifold and the head. I used a belt sander to grind it smooth and flat again, put it back together with a new gasket and now it's fine.

I haven't thought about that! Il take a look this weekend, thanks for the tip!

 

[LobstaMobsta]

Cast iron can not be welded

 

[inscarguy]

if its a toyota certified vehicle its under warranty, mine were replaced by toyota under this warranty for -0- money out of pocket.

 

[WXman]

My manifolds are toast too. Engine sounds like a jalopy especially when engine is not to full temp. 106K on mine.

From everything I've read, the Pace Setter replacements seem to be the way to go. They are about $280 each side and are made of stainless steel. Allegedly they are a direct replacement, but that assumes your flanges on the down pipe are not rusted together like mine are.

 

[chaz]

Guidelines for Welding Cast Iron

 

[BlackWorksInc]

Cast iron can not be welded

This isn't entirely correct...

Guidelines for Welding Cast Iron

You can weld cast iron, I've seen it done by my welding instructor in college many times when repairing cylinder heads and blocks for people. It is ridiculously difficult work and requires specialized rods and technique. The reason most people believe it is impossible to do is because of the nature of cracks in cast iron. They tend to spread as you weld the original crack due to thermal expansion and so you play a game of "chase the crack" it takes a great deal of experience and technique but it can be done effectively.

Unfortunately in the case of the OP he would need to remove the exhuast manifold anyways to be able to properly weld it anyways. I do not believe our manifolds are cast iron as they are welded to the catalytic converter housings which is stamped steel. There was a post a long time ago about a member who sucessfully welded the crack in his manifold near the cylinderhead, I do not remember if the manifold was removed or not for this repair.

There are limited aftermarket options for our 4.7L V8's in the 4Runner application. A member was able to modify Tundra headers to fit his 4Runner, I also remember seeing someone talking about performance custom headers for a while. I believe they are only for the VVTi models (I have not bothered to look at why and/or if the manifolds are any different than the pre-'05 models.)

Post Note-

It is worth mentioning that modifying your exhaust in any manner besides OEM (i.e. putting new manifolds that do NOT have the primary catalytic converters) voids emmision regulations and could be subject to fines, penalties, failure of smog/emmision testing (assuming your state/region does this,) ect ect.