Cracked Exhaust Manifold

[DenaliHD66]

There like aren't any other options though?

 

[CaptainXL]

There like aren't any other options though?

There are at least two other manufacturers who make a replacement version of our manifold.

 

[DenaliHD66]

Welp. Got it today. The Dorman. I wasn't expecting perfect, but this thing seems like complete garbage. Can someone confirm whether or not this is complete crap or something else is manufactured out there? The casts are rough around the ports, the bolt slots are all different sizes, the 2 most distinct ones being in this picture. The gasket has odd sized holes too.

 

[CaptainXL]

Get the one from APDTY.com. It is made and looks 200% better. Sure you will need to buy the gasket and doughnut separate but hey it is what it is. I spent a lot of time researching this.

[video=youtube;mW5PxWG7POc]https://www.youtube.com/watch?v=mW5PxWG7POc&feature=youtube_gdata_player[/video]

 

[DenaliHD66]

OK cool. There are 2 lengths of bolts to choose from, there is 2.190 and 3.190. Which ones will I need to pick up?

Is this the same manifold or yet another manufacturer?
Amazon.com: ATP 101403 Exhaust Manifold: Automotive

 

[DenaliHD66]

Spoke with a rep from APDTY, he said their branded one and the Dorman are the exact same part, same manufacturer. I think I'll just keep mine, file down the rough casting in the ports, and spare myself more shipping/ordering headaches. Still need to order the bolts though.

 

[CaptainXL]

Mine never had any rough casting parts. If you look at the video you dont see any as well. Mine came in very nice condition. Much different than what your Dorman looks like.

Edit: Just went to APDTY.com website and it appears they changed suppliers for the exhaust manifolds. They are using Dorman now. Mine obviously came from a different supplier. Got it almost 2 years ago. Sorry for the bad luck. If you can find the one I got that would be to your advantage.

 

[vipergg]

How do you know if it's cracked ? I always thought the exhaust was a little louder than it should be but there no other operational difficulties. Runs great.

 

[DenaliHD66]

How do you know if it's cracked ? I always thought the exhaust was a little louder than it should be but there no other operational difficulties. Runs great.

You will hear a knocking sound coming from the side where the header is. Stick your head under the wheel well and you'll hear a definite knocking sound... sort of like a "no exhaust" sound but baffled.

 

[CaptainXL]

You will hear a knocking sound coming from the side where the header is. Stick your head under the wheel well and you'll hear a definite knocking sound... sort of like a "no exhaust" sound but baffled.

Yep but there is a possibility the manifold is not cracked but instead the gasket could be loose or bolt broken off at the head. I ordered a new manifold and gasket only to find out I never had a crack. All I had to do was replace the gasket. So I am left with a perfectly good manifold sitting in my garage.

Really the only way to know for sure that it is cracked without removing it is by visual inspection. Can be hard without mirrors and such if the crack is on the back side.

 

[nike0777]

Hello,
I have an 08 Trailblazer that had a cracked exhaust manifold that was replaced under the special warranty about two years ago. Now the new manifold has cracked in half. I reached out to Chevy and am awaiting an answer as to whether or not they will cover the replacement again. Has anyone else had the manifold crack again after being replaced? If so did Chevy cover the second break or only the first? It seems crazy I should have to pay for a cracked manifold only two years old if they are obviously having issues with the product their putting in.

Thanks for any help or info!

 

[IllogicTC]

Wandered into this thread rather accidentally, but figured I could contribute. Anyone looking for the 10.9 grade exhaust manifold bolts, here's an Amazon link from Dorman:

Dorman 03413B Exhaust Manifold Hardware Kit : Amazon.com : Automotive

11 bolts to match up the manifold and gasket to the block. The manifold itself from Dorman comes with heat shield, doughnut, bolts for linking to the exhaust and the gasket, don't get why they don't just make a combo kit with these included since I've seen a bunch of complaints about the bolts breaking on extraction, but here they are for $8.99 for the set.

I know I'm late to the party, but now it's here in case anyone else needs the info

 

[09GMCSLT]

Im on my third exhaust manifold first one was replaced at 120,000 I'm at 190,000 and it sounds like a tank. Has anyone found anything better than stock to replace the exhaust manifold?

 

[Mooseman]

I bought some no-name one from eBay years ago that said specifically they were improved in the areas that usually crack. It outlasted the truck. In fact, when I scrapped the 02, I kept that manifold for the eventual crack I will get in my 07.

However, you have an 09 and choices are limited. Dorman is supposedly improved in those areas prone to cracking. Would definitely be worth trying instead of the overpriced failure prone OEM. They do have a lifetime warranty.

 

[09GMCSLT]

I bought some no-name one from eBay years ago that said specifically they were improved in the areas that usually crack. It outlasted the truck. In fact, when I scrapped the 02, I kept that manifold for the eventual crack I will get in my 07.

However, you have an 09 and choices are limited. Dorman is supposedly improved in those areas prone to cracking. Would definitely be worth trying instead of the overpriced failure prone OEM. They do have a lifetime warranty.

Ive read about ceramic coating the exhaust manifold but that's another 200 bucks , I've built headers before wondering how hard it would be to make one out of stainless and coat that, call me crazy but it's been a good trick

 

[Mooseman]

There used to be headers available but I think they were for the earlier engines. Might be worth a look.

 

[mrrsm]

File Not Found - DragTimes.com

parts

www.dragtimes.com

Price: $720.71



Allmotorsports11

​

OBX Racing Sports™ offers an extensive range of high quality aftermarket automotive products for imports and domestic vehicles. OBX Racing Sports™ sets and maintains the industry's high standards by using the highest grade materials and latest machinery along with advanced cutting edge manufacturing technologies.

Product:

• OBX Racing Sports™ Header and Pipes (5pcs)

Application Fit For:

• 2002-2006 ChevroletTrailblazer 4.2L I6
• 2002-2006GMC Envoy 4.2L I6
• 2002-2006Buick Rainer 4.2L I6
• 2002-2006Oldsmobile Bravada 4.2L I6
• 2002-2006Isuzu Ascender 4.2L I6

Specification:

• Mirror Polished Finish
• Made Of Stainless Steel
• Primaries: 1.65" OD
• Port ID: 1.25" ID x 1.95" ID
• Collector: 2" OD
• Outlet: 2.75" ID
• Main Piping: 3" OD
• Resonated Application( No Cats)
• OEM Outlet Pipe Connection to Stock Exhaust
• Flange Thickness: 3/8"
• Runner Wall Thickness: 16 Gauge (1.5mm)
• Requires O2 Extension Wires
• 1 O2 Bung

General Information:

• Improve performance, efficiency, and horsepower
• Made of quality materials for longevity and durability
• Individual port design for continuous even exhaust flow
• Mandrel bent for ultra-smooth fast exhaust flow
• Computer Numerical Control (CNC) machined flange for precision fitment
• Dual Tungsten Inert Gas (T.I.G.) welding for stronger hold
• Included all accessories shown on the photo
• No installation instructions with this kit, we recommended professional installation
• Free shipping is for the lower 48 states only(All other locations must contact us for shipping quote. See disclaimer for more information)
• Manufacturer's backed limited lifetime warranty against manufacturing defects (must return warranty card to manufacturer)
• Contact us through eBay messages for any questions

 

[Mooseman]

His is an 09 so might not fit. Pricey too.

 

[mrrsm]

Just letting others looking in know that ...for an AWFUL lot of Money...THIS one is still available out there for the Early Model GMT360s. It occurred to me that by taking a Late Model MLS Exhaust Manifold Gasket and laying it across a 4" X 36" X 3/8" thick piece of 304 Stainless Steel...a modded version from THIS Rare One might emerge if such a Need was Matched Up with a THICK Wallet and Much Determination. :>)

 

[mrrsm]

These "Kooks" were pretty functional you know (and I use that Word as a Brand Name... without any pejorative association to the VOP "Fishsticks"). But as with all of them... THEY WERE ALSO WAY TOO EXPENSIVE BACK THEN!

The Post Install Start-Up:

And the requisite Follow Up Test Drive: