Engine/Transmission (1998.5 - 2002) Cracked Exhaust Manifold

[Holzarbeiter]

I did a search on this and couldn't find anything. The Manifold is cracked right at the y where the two center castings come together. There is no major discoloration at the Manifold, the temps have never gone over 1200 and all the hangers are tight and in good shape. There are no signs of any damage around the Thermocoupler. I don't have a major power loss just the boost # seem a little lower. What causes this? To much heat? Bad casting? I want to make sure I solve the problem if i have one.

I know that ATS has a three part replacement, are there any other options?

Thanks



P. S I replaced the K&N with a Bhaf recently, if anything i would think it would have helped not caused the problem, any thoughts?

 

[JFinke]

The manifold heats up and expands, and shrinks when it cools. Eventually it will shrink more than the bolts will allow and it will split in half. Thats why the ATS has three pieces to allow for these cycles. A new one will eventually do the same thing or break off the mounting bolts and cause the ports to misalign. Buy the ATS or plan on doing it again. Mine was replaced under warantee and will get an ATS three piece next time on my dime. Jake

 

[Bob4x4]

The 24v s are a very thin casting,it is not uncommon to see them crack. The ATS 3 piece is the best answer @ this time. I understand they have been bought out by ATS transmissions and may be using a different foundry.



Bob

 

[rodneync]

My 98. 5 had several cracks in the manifold-- my truck is completley stock. I bought a new stock manifold from the local dealer. It appears that the new manifold may have slightly thicker walls, but by the time it was all said and done, the ATS would have been the same price and probably more durable. Next time . . . ATS.

 

[TSRAM]

Once you remove the factory manifold and take a look inside, you'll see how it can crack. These things are paper thin compared to the ATS. It surprised me to see how closed in the ports are on the inside. The ATS is at least twice as heavy with better flowing ports.

I won't tell you that it's faster or uses less fuel than the stock one. I went a little further and did about an hours worth of porting on mine just to round some of the sharper coners inside. Considering how close the stock manifold is in price I wouldn't even consider going with it again.