Cross-Over Pipe Problem
 

I recently removed the Intake Manifold and Cross-over pipe to replace the manifold gasket (amongst other things). I had both parts hot-tanked and bead-blasted to remove all the crud inside so they were squeaky clean when reinstalled.

Problem is when I tightened up the flange on the Cross-over to manifold one of the Allen Screws would not seat properly and it looks like the thread is partially stripped. I used some gasket sealant but the joint is now leaking.
Short of removing the Intake (Again :mad: ) and fitting a Helicoil in the stripped thread, does anybody have any other ideas for a possible fix?
Would some type of Thread Locker work?

My other concern is that there is a little oil residue seeping from the flange. Does this indicate a Turbo Oil Seal problem? :eek: (My EGR is removed and blanked off BTW). If so how easy is this to repair?

Andy, can't you deal with the bad thread right on the vehicle? That thread is readily accessible at the top of the engine, correct?? Putting a Helicoil in it would be easy for a machinist.

Also, can you comment on who did the hot tank on the aluminum parts? What solution did they use?

I've been told that they can't hot tank aluminum due to the problems with chemical decomposition of the aluminum.

I hot tanked my 603 intake manifold with no problem, although it used a solvent which is a petroleum based liquid (and "banned" in some places!)
You don't want to use a strong alkali on aluminum (ie. oven cleaner).
I also used some engine degreaser that is a citrus based stuff available from Granger's http://www.grainger.com/Grainger/productdetail.jsp?xi=xi&ItemId=1611757438&ccitem=

Neither the hot tank or the spray-on citrus stuff completely removed all of the gunk, I had to use a rag wrapped around long nosed (11 inch) pliers to scrub the stuff off with carb cleaner (toluene based stinky stuff!).
I doubt there is much gain in air flow characteristics from a squeaky clean manifold but it's nice to know you can see the base metal when reassembling a manifold onto a rebuilt engine.

Sounds like normal oil getting past the turbo bearings, they aren't a perfect seal because some oil flow is necessary past the bearings, they float on an oil film you know. If you have too much past the bearings you will see smoke under acceleration.
There is some belief that one reason some 350SD engines failed with bent rods is due to carbon build up on the top of the piston which may be caused by leaking turbo bearings. That is just a theory.

I think the threaded hole is open to the intake manifold, so I was concerned that any threading for a helicoil might put filings into the intake. I will check though. Maybe I can just fit a helicoil into the existing thread and use a smaller diameter bolt.

I'll try and find out what it is they used Brian. I did ask before I left the parts if it was OK to use with Aluminum and I was assured it was fine and that they use the same thing to clean out Aluminum Cylinder Heads. They also said that the hot-tank would remove some of the loose/soft crud, but that a bead blast would be required to get the rest.

Thanks Dieseldiehard, That is good news about the oil. I don't get any oil smoke except a little at cold start-up.