Engine/Transmission (1994 - 1998) Shrinking exhaust manifold

[KEnhoffer]

I recently had my valves adjusted by the good people at Auto Wurks. A manifold problem was brought to my attention. It was shrinking and pulling back linearly from the #1 and #2 cylinder ports. Mike said that eventually the mounting bolts will crack the flanges on the cylinder head. Having the good fortune to have purchased an extended warranty (which has paid for itself). I brought the truck to the dealer. The service manager thought I was crazy, but a mechanic verified the problem. DC replaced the manifold. The service manager claimed he had never seen this before. I do recall a post about this happening due to poor quality in the manifold material. I was wondering if any other member have experienced this. My truck has only 50,000 miles on the clock and has not been bombed or driven hard. Although new mounting bolts were ordered along with the manifold I see that the mechanic only installed 6 new mounting bolts and put the used ones back in the remainder. The only time DC will see my truck is for warranty work.

 

[Bob Wagner]

BIG BOBS manifold develop a little crack

click







click2

 

[HoleshotHolset]

It is common for the #1 cylinder to run a tad bit hotter than all the rest due to a Cummins manufacturing flaw or obstruction in the #1 intake runner (if you want to call it that... )... . less air = hot EGT's



These increased EGT's will cause the gaskets to fail and the manifold to warp in weird ways and sometimes crack. I see more failing gaskets on the #1 cylinder than anywhere else on the many trucks I have worked on.



Hope this helps,



Matt

 

[grtescpa]

Originally posted by KEnhoffer

I recently had my valves adjusted by the good people at Auto Wurks. A manifold problem was brought to my attention. It was shrinking and pulling back linearly from the #1 and #2 cylinder ports. Mike said that eventually the mounting bolts will crack the flanges on the cylinder head. Having the good fortune to have purchased an extended warranty (which has paid for itself). I brought the truck to the dealer. The service manager thought I was crazy, but a mechanic verified the problem. DC replaced the manifold. The service manager claimed he had never seen this before. I do recall a post about this happening due to poor quality in the manifold material. I was wondering if any other member have experienced this. My truck has only 50,000 miles on the clock and has not been bombed or driven hard. Although new mounting bolts were ordered along with the manifold I see that the mechanic only installed 6 new mounting bolts and put the used ones back in the remainder. The only time DC will see my truck is for warranty work.

Buy the 3 piece manifold advertised in the Turboregister. I did. Works great. Has better porting.

 

[drees1]

Common problem.



I believe what we are seeing is lack of clamping force at the flange to restrain the manifold when cooling from a high load excursion, and Cummins has pushed the limit on the design length of the manifold.



Under high temps the manifold can expand and it must yeild at high temp. Then, it contracts when it cools and becomes shorter than when it started. Over time it is a problem. Just something to watch for.



Doug Rees

 

[fortunate1]

Big Bob:

I clicked on the first picture link in your post, and wondered if that crack was on the top or the bottom of your manifold. Then I clicked on the second one, and saw that the answer was "yes, it is!" Wow. Is the drilled hole in the second pic where your Pyro probe used to live?

 

[SMorneau]

Ok, I know how to diagnose it after it has cracked or broken something, but what do I keep an eye on prior to damage?