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RickGyver · 07-07-2012, 05:43 PM

I just removed the exhaust manifold and the turbo had to come out too because the exhaust gaskets blew out and lost alot of boost. Also broke 4 exhaust bolts. (I think I have bruised ribs!) I plan to have exhaust manifold surfaces machined so they are flat against the head again. '95 Dynasty 8.3L had any cracking problems ? As long as these parts are sitting on the bench,,,,, if you've been thru this before,,,I'd appreciate any advice! I want to upgrade the bolts also. thx

Mike Canter · 07-07-2012, 08:25 PM

One thing I have learned over the years is that the Prermatex Gold high temp silicone sealer works very well on sealing exhaust gaskets. I have never had an exhaust manifold gasket blow out when it has been used. Don't know if you have bolts or studs. If studs then probably don't want to remove the old ones. I used all grade eight cadmium plated nuts, washers and bolts. On one engine I used all stainless steel hardware. Use a tork wrench on the fastners you can reach. After a couple of hundred miles retork all again. Tighten those manifold fastners in sequence and a little at a time so you don't crack it.

mahon1993 · 07-07-2012, 08:35 PM

Had the same problem with my 2000 ISC with 70k on it. The manifold warped and snapped off a couple of bolts. Mine is a two piece manifold. Had it resurfaced and replaced all the bolts and gaskets. Worse part was removing the busted off bolts from the head. You will probably need new turbo gaskets too. Sure is fun laying on your stomach and wrenching.
Greg

mahon1993 · 07-08-2012, 08:27 AM

Also, I bought the right size metric tap , I forgot what size, to clean up the threads in the head.
Greg

EngineerMike · 07-08-2012, 08:41 AM

Note to self: put PM R & R & anti-seize on the to do list.

slickest1 · 07-10-2012, 03:02 PM

I had to replace the exhaust manifold on my 01 8.3 cummins. It cracked, and I was told by Cummins that it is a common problem. On the bolts sometimes an impact wrench will loosen them without breaking the stud. Sounds like it's too late for that. Good luck with your project.

RickGyver · 07-10-2012, 06:20 PM

Quote:

Originally Posted by mahon1993

Also, I bought the right size metric tap , I forgot what size, to clean up the threads in the head.
Greg

10mm x 1.50

RickGyver · 07-14-2012, 06:08 PM

Had the old manifold resurfaced but it has SHRUNK quite a bit. I have since ordered the NEW style exhaust manifold....under $300. Cummins has changed the design twice. Old manifold will do for now!