Best Replacement Options for Cracked Cummins 5.9 ISB Exhaust Manifold

[MEOWMAN]

HAVE A 2000 FLEETWOOD BOUNDER WITH A CRACKED CUMMINS 5.9 ISB. IS THERE ANY OTHER OPTIONS BETTER THAN THE OEM ONE ?

 

[House Husband]

The OEM ISB one piece exhaust manifold is a known problem.
The aftermarket 2 piece is a more durable manifold.

Richard

 

[BillyThib]

HAVE A 2000 FLEETWOOD BOUNDER WITH A CRACKED CUMMINS 5.9 ISB. IS THERE ANY OTHER OPTIONS BETTER THAN THE OEM ONE ?

BD Diesel Performance has a 3-section manifold that has been around for decades that addresses this problem!

 

[billbenham]

My unit had a cracked 2-piece manifold when I bought it last year. Replaced the cracked section with one from eBay and 6000 miles later no problems. Also got the gasket set from eBay.

 

[TheBar]

Be aware many exhaust manifolds crack because the bolts were overtightened. And that can also crack the cylinder head. Use your torque wrench. If you don't have the specs don't crank down on the bolts.

Also be aware the exhaust pipes attached to the manifold can also be the reason for the manifold cracking. A damaged or new pipe that is over or under bent or not the exact right length will place a strain on the manifold causing it to crack. If you have to pry to attach the pipe, fix the pipe and save your manifold.

Thirdly, if the engine is running too lean the manifolds can overheat. I lifted the hood on my truck once and the right manifold was glowing red-orange. Even though it ran fine it needed a richer mixture.