DIY Exhaust manifold replacement

[cbetts]

Pulled off the heat shield today. Manifold is worse that I thought.

Time to do more research.

 

[hockeymanam]

and once you take it off i promise you find more cracks on the inside!! I had one in the same spot as yours, but once i took it off there was two more internally!!

 

[Mr_Rich]

Uh-oh. The question I have is IF I somehow acquired a Magnaflow cat/ header; how long would it be before I have to get smog-tested and required to remove the header before the smog test? Hmmmnnn....
I have a feeling that the part is good enough to pass the sniffer, but not the visual test. Magnaflow probably didn't want to invest in the lengthy and complicated procedure to get the part to pass CARB or the EPA.

 

[cbetts]

I need to talk to a few people in the business to see what undocumented options I may have.

 

[06 H3]

when mine goes out I will ship it to my family in NY and have them forward it out to CA.

I like the magnaflow one. I could use some added HP.

 

[JonBishop]

If u smog it and have a magnaflow on with the heatsheild back on, how would they tell its different then OEM?...


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[06 H3]

they will not know a difference visually with the heat shield but I am not sure how it would do on the actual test.

 

[telemike]

Bosal North America makes an OEM 49 state manifold too.

 

[digglesworth]

I believe someone said you can't mount the heat shield back on with the magnaflow. Probably the same across the board with any header. That's means you cali people gotta be extra crafty.... :thumbs:

 

[telemike]

Bosal

079-5230

Manifold Catalytic Converter - Manifold,Not legal for sale in CA. Not legal in NY for vehicles with CA emissions

I think you can get this for way less than list = 895.74 . One parts house I called quoted me $360

 

[4speedfunk]

So I got a couple questions....

1. Did you guys with the cracked stocker notice anything while driving?...or did you just visually see the crack?
2. Does a header like this actually "flunk" an emissions test? Seems like it would perform better.

 

[alrock]

Mine's cracked above the cat, maybe 1/3 to 1/2 way around. Physically torn, so it's a bit different than many of the other cracked headers. When I start the truck up I get the smell of unburned fuel that would normally go down the exhaust and out the back, at least until the cats heat up. Ironically, my exhaust seems a bit quieter now, perhaps as less air is getting pushed through it.

Last emissions test was 20 months ago before the header failed so I can't speak to passing the test but I don't think it would be an issue.

 

[cbetts]

So I got a couple questions....

1. Did you guys with the cracked stocker notice anything while driving?...or did you just visually see the crack?
2. Does a header like this actually "flunk" an emissions test? Seems like it would perform better.

1) Yes. I had an audible exhaust leak along with a squeeky-rattling sound. I have had issue with the flange below the cat leaking from hitting rocks over the years so I assumed it was that until I pulled the heat shield off. Also had a visually apparent black mark on the back side of the shield from the leak.

2) Not known yet. I have flunk smog tests in the past from exhaust leaks.

 

[chaos254]

I think mine might be cracked too, smell exhaust/fuel smell on startup and then it goes away. When it gets warmer I'll pull the heat shield to verify.

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[CaseyS]

Not sure if its appropriate to post this here but I have a functioning exhaust header that I will pull off my takeout engine for anyone that needs a replacement. Make a reasonable offer. This one was changed about 2 years ago so its not that old. The cat is built into the part so it's not a cheap replacement. I think I paid $5xx for it new.

 

[alrock]

That's for the 3.5, right? Shoot, I need a 3.7L header.

 

[cbetts]

Post a picture showing the numbers on the cat. This will show if it is legal for us in Commiefornia.

I would have jumped on it but I just had mine replaced yesterday. Went with a CA legal replacement from the dealer.

 

[Airborne]

Hey guys I am about to undertake this project this week with an after market ottp header. My purpose was primarily for performance upgrade. I removed the heat sheild the other day to soak the bolts for the next week with pb blaster to ease them getting out. Anyway I noticed that the head on bolt no 1 (closest to the grill) was snapped off. There is about 3/4" of thread still sticking out of the head hopefully it will still come out with an extractor set. The second thing I noticed was I had a crack in the exact same spot as cbetts, in fact I would swear he took a pic of my manifold. So it looks like the header replacement is a necesity at this point. I have looked for 3 weeks now to get the exhaust bolts, no one has them. Everyone has a stud set. Is there any difference with the two or did GM do away with the bolts in place of studs? Also any suggestions on removing that no 1 bolt shaft??

 

[rsc]

If there is still 3/4" of bolt thread sticking out of the head I would just grab a pair of vise-grips to get it out.

 

[alrock]

I just ordered the bolts from Zach about two weeks ago. He either has them or can get them in a day or so.

 

[Airborne]

I just ordered the bolts from Zach about two weeks ago. He either has them or can get them in a day or so.

I appreciate that. Zach, is that his name on the forum here? Also you are welcome to my 3.7 manifold. It has the single slight crack in it but I don't think it's leaking at all. There arent any signs of a leak that is. I have had jeeps before and I would say it's noticeable with an exhaust leak. Any way it's yours if you want it, maybe you could throw a bead on the crack before it goes all the way through?? If you want it cover shipping and it's yours. I will take more pics for you once it's off if you want it.

 

[rascole]

Wow, this appears to be a problem that is rearing its ugly head (pun intended) with higher mileage I5's with cast manifolds. I started another thread with my 06 so hopefully we can come up with a few good solutions for the future. I just talked to Magnaflow and the reason he said it is not CA legal is strictly the cost of getting the stamp of approval from the CARB (California Air Resource Board). This I am familiar with. Manufactures are responsible for extensive and costly testing of products before they will give approval. BS in my opinion if will pass federal why not Cali. Either way he said that he guarantees it will pass tail pipe emissions just not visual, if I was even able to get it shipped.

 

[cbetts]

Wow, this appears to be a problem that is rearing its ugly head (pun intended) with higher mileage I5's with cast manifolds. I started another thread with my 06 so hopefully we can come up with a few good solutions for the future. I just talked to Magnaflow and the reason he said it is not CA legal is strictly the cost of getting the stamp of approval from the CARB (California Air Resource Board). This I am familiar with. Manufactures are responsible for extensive and costly testing of products before they will give approval. BS in my opinion if will pass federal why not Cali. Either way he said that he guarantees it will pass tail pipe emissions just not visual, if I was even able to get it shipped.

Well, that is the catch . . . passing the visual. I had to explain the law to the inspection station with my Air-Doc and how I was still running the factory air box. I was not ready to pull the trigger on the cat. Could have been a $600+ mistake. Maybe when I transfer to Texas . . .

 

[rascole]

I get my smog done by a friend of the family at their garage so I'm not worried about visual inspection. Did yours pass smog with the crack? Mine still throws the P0171 code. May be time for JB Weld just to pass smog.

 

[cbetts]

I get my smog done by a friend of the family at their garage so I'm not worried about visual inspection. Did yours pass smog with the crack? Mine still throws the P0171 code. May be time for JB Weld just to pass smog.

Last smog was July 2012. I did have an exhaust leak back then but it was a from a tear in the flange just behind the second cat and was not showing a code.. OBD was not showing a code with the cracked manifold either.