Hello, I was just under the hood of my truck 99 2500 diesel, when I noticed a nice hairline crack from the center of the 4 bolt flange clear around from top to bottom. Is it ok to drive till I get another manifold or will I cause more problems?

 

It's not into the flange yet.

 

yes, but don't get on it as you will lose boost.... how long has it been cracked?

 

It'll be fine to drive, as john said you will loose some boost when you get on it however.

This is the bottom of mine, you don't even want to see the top....and it was like this (the bottom) for probably a year...

 

john, I've only had the truck a week. I did'nt notice it until yesterday. Dinner, thats exactly where mine is cracked. It's not into the flange yet, and there's no black residue exept right on the crack so must be fairly new. Is this common with the 24v? Any Idea of the cause? The engine is stock except for an aftermarket aircleaner.

 

a lot of the 24 valve manifolds crack in the same place. the cause is probably from excessive EGTs and rapid cool down, my manifold is original with over 200,000 miles.
when you replace it, go with OEM, it's the least expensive way to go...... unless you want a performance up grade. but i don't think the 3 piece manifold will give you much for the cost

 

here's a manifold thats interesting, the listing has expired but you can call the guy
http://cgi.ebay.com/ebaymotors/ws/eB...3AIT&viewitem=

 

That's a pretty cool lookin header!

 

The cracking comes from heat expansion and cold contraction. I don't believe egts need to be excessive for this to happen, I've seen it happen to totally stock manifolds on trucks that never haul anything.

Don't replace it with an OEM, the problem will likely reoccur. Spend the extra money for a three piece manifold that compensates for expandsion/contraction.
If you look at the exhaust manifold of almost any big rig you'll see that they are multiple piece for this very reason.

 

The crack in mine continued to grow - as Infidel says - I replaced with an ATS 3 piece. It was a problem with factory manifolds.