Cracked exhaust manifold question V8

[stevec5000]

Thanks for the links earlier. I hadn't seen the outside one. It's apparently more of an issue than I had thought.
I don't recall any reports of an emissions fail because of it, though. Do you?

A small to medium exhaust leak can't cause emissions failure unless it's so bad the O2 sensors don't work correctly and causes an error. The noise would be intolerable by that time however.

 

[V8Man]

The stock headers on both of the 2003 V8's I have are not cast iron. They are made out of tube steel, like aftermarket headers. I pulled two engines for an engine swap and removed the heat shield to look at them. Look in the picture I have the heat shield off.

 

[BlackWorksInc]

Toyota hasn't used castiron headers since they went with the all-in one header/catalytic converter set-up.

 

[TRDCal]

In most cases when you replace the stock parts with an aftermarket header it makes it LOUDER since the tubing used is usually thinner so I don't think your conclusion is correct.

Not so sure about that. Its all about flow, the faster air flows the more noise it makes. Just think about wind noise, is it louder when going 10mph or 110mph? When I installed dual exhaust on my truck, it was alot louder that stock but its not because the metal used is thinner.

You probably just had an exhaust leak due to the header being warped and not sealing against the head properly

Not even sure if your serious here...did yah see the title of the thread?

There isn't any from the ones on my 4L V6.

It's only known to happen on the V8, V6 owners are in the clear.

Thanks for the links earlier. I hadn't seen the outside one. It's apparently more of an issue than I had thought.

I don't recall any reports of an emissions fail because of it, though. Do you?

Not a problem, anything for friendly member.

I'm not sure the actual emission coming out of the tail pipe are affected but that's only part of the inspection. The other part is the visual (audible) inspection where they make sure that the catalytic converters are still there and that no leaks are evident etc etc. It will also cause the vehicle to fail safety inspection since the leaking gas "could" enter the cabin

EDIT: Just to be clear, that's how the inspections work around here (Ontario, Canada). It's entirely possible that it could pass inspection elsewhere

 

[Nathana92]

In most cases when you replace the stock parts with an aftermarket header it makes it LOUDER since the tubing used is usually thinner so I don't think your conclusion is correct. You probably just had an exhaust leak due to the header being warped and not sealing against the head properly in which case it's easy to fix just by grinding it flat and installing a new gasket. I had to do that once on my pickup. There shouldn't be any noise from the stock headers if they fit properly. There isn't any from the ones on my 4L V6.

I seriously doubt that the material used on the stock MANIFOLD is thicker than the stainless steel HEADERS. I installed. Yes they are louder and provide more power because they provide better flow, 1 tube per cylinder is better than 1 per 4 cylinders. There isn't any noise until they crack, that's the issue.

 

[tollboothwilley]

The OEM header design really is a horrible one. I am shocked that the aftermarket people haven't done more to find a better solution for replacement.

Even a cat-delete option for "off-road" use would be so valuable. Maybe I'll see if I can find a company who will use an existing design that fits the V8 and modify for off-road on the 4runner.

 

[WXman]

Not true! None of my cars or trucks have ever had an egg smell. The 4R certainly doesn't have it.

Have you been behind your cars while going up a hill? Guarantee it'll choke you to death. It's a product of how Toyota cats are made, as I said earlier. They all stink like hell (while everything is rusting).

 

[jminz]

For starters, in some states it will not pass inspection with a leaking exhaust. Were I live we're required to pass and an emission test every 2 years an exhaust leak is an immediate fail.

More importantly for me, I'm driving a beautiful, once upon a time 40k truck that sounds like a old beater POS. For that reason I'm getting mine fixed and if you think a grand is alot, up here the manifolds from Toyota cost over $1200 EACH not including installation.

I didn't realize it got that loud

 

[TRDCal]

I didn't realize it got that loud

In the beginning it would quiet down after the truck was warmed up but now it ticks all the time, worse when the engine is cold or under load. I can't hear it with the windows up and music on but its embarrassing to drive through town especially between tall buildings or in tunnels.

 

[WXman]

In the beginning it would quiet down after the truck was warmed up but now it ticks all the time, worse when the engine is cold or under load. I can't hear it with the windows up and music on but its embarrassing to drive through town especially between tall buildings or in tunnels.

Yeah, if you've ever heard a steam locomotive trying to get a load going... that's what my truck sounds like. Spit, sputter, spit, sputter, spit, sputter.. It's not a ticking noise. It's more of an air spitting and sputtering kind of sound like a valve letting off steam. It's annoying as hell.

So these manifolds are not iron? I learned something new today. So that means that if they are steel...they should be weldable, right??

 

[TRDCal]

So that means that if they are steel...they should be weldable, right??

Correct, guys (and gals?) have had them welded before. They tend to last about a year before they recrack.

 

[V8Man]

Yes they are tube stainless steel, most probably 304 Stainless Steel. This requires the welder to use stainless steel rod or wire. Also the crack needs to be properly prepared before it is just welded closed. I have seen guys use regular steel rod or wire, it doesn’t last.

 

[WXman]

Ok, here's another dumb question. Is it a MUST to remove the manifold from the truck to weld it up?

My thinking is that labor would cost more than parts...and if you HAVE to remove the manifolds, you might as well replace them with new ones.

 

[Nathana92]

Ok, here's another dumb question. Is it a MUST to remove the manifold from the truck to weld it up?

My thinking is that labor would cost more than parts...and if you HAVE to remove the manifolds, you might as well replace them with new ones.

It would depend on where the crack is, welder skill, and just how much room there is.

 

[TRDCal]

Ok, here's another dumb question. Is it a MUST to remove the manifold from the truck to weld it up?

My thinking is that labor would cost more than parts...and if you HAVE to remove the manifolds, you might as well replace them with new ones.

There's no such thing as a dumb question, only dumb people

Jokes aside, I would put my money on needing to remove them. Not sure how skilled your welder is but there's not much room between the manifold and frame rails. Our frame is 4inch narrower than the Tundra with the same motor so its definitely tight.

The stock manifolds are ridiculously expensive $1200 each (not including gaskets or installation) in Canada and I believe around $800 in the states. So some people rather get them welded and it is cost effective if you remove them yourself. But if your having a garage remove and weld them every year (roughly) then yah it probably wouldn't be worth it.

 

[Nathana92]

The stock manifolds are expensive. The tundra manifolds should fit but they don't have the cats connected. It'd be interesting to see I'd someone could put tundra manifolds on and re use the cats from their manifolds or go without.

 

[WXman]

Yeah the Pacesetter manifolds are $500 for the pair. That's the only way I would go. I might look into getting these welded first though and try that. Will get a quote sometime this summer.

 

[TRDCal]

Yeah the Pacesetter manifolds are $500 for the pair. That's the only way I would go. I might look into getting these welded first though and try that. Will get a quote sometime this summer.

I wonder how well they'll hold up....but I suppose they can't be any worse that the OEM ones

 

[joeschmoe]

I've had the loud exhaust tick problem from one manifold for a year now. (2006 V8 107000 miles)

I take it no one has tried the Magnaflow headers? They claim a direct fit but of course the same headers are spec'd for the GX470 so they might not fit.

A genuine Toyota manifold would likely cost $750 if purchased online and shipped to Canada. For $1000 CDN I could get both left and right Magnaflow headers!

 

[TRDCal]

I take it no one has tried the Magnaflow headers? They claim a direct fit but of course the same headers are spec'd for the GX470 so they might not fit.

For $1000 CDN I could get both left and right Magnaflow headers!

Have a link?