Exhaust leak upstream of turbo (6V92TA)

[lyndon]

I recently replaced the L-shaped pipe between to pax-side manifold and the "Y" feeding the turbo due to cracks and rust rot at the flare. After tightening the clamps (as much as I dared), I can feel leakage at both ends. Generous amounts of liquid gasket did not seem to help. Am I missing a seal or gasket that should be installed in the joint? (Sorry if this has been asked before, but I can't find a clear answer in my searches.)

Thanks,

Don

[Tim Strommen]

Two questions:

1)  Did you clean the ends of the pipes (both the new, and existing) before you reconnected everything?
2)  Did you use new compression seals?

The compression seals are supposed to be torqued down - I don't recall the number... (anyone?)

If there is carbon buildup on the pipes, it may be preventing the ends from seating properly.  The bands are throw-outs, and shouldn't be used twice (they get brittle with age).  I haven't personally heard of anyone using liquid gasket on exhaust pipes before the turbo - that exhaust gas is about 700F to 1400F depending on engine load, not much but the cast iron can tolerate direct contact to that temp...

-T

[luvrbus]

I have good luck rotating the clamps 2 or 3 times      good luck

[lyndon]

Two questions:

1)  Did you clean the ends of the pipes (both the new, and existing) before you reconnected everything?
2)  Did you use new compression seals?

1) I cleaned the ends of the existing ports with a wire wheel on a drill and vacuumed out the debris; the new pipe looked pretty clean (with a light greasy coating).

2) Compression seals? Is that different from the V(?) clamps that tighten the whole works together?

Don

[Tim Strommen]

2) Compression seals? Is that different from the V(?) clamps that tighten the whole works together?

V-Clamps = compression seals.

I forgot to look in da book for the torque value last night - sorry.  The joints should be about air tight after assembly, the clamps squeeze the pipes together a bit more to squeeze any minor deflections that would otherwise seal it.

You can take the works apart again and put a little chalk on one side of the pipe, them reassele.  if you take it apart again, you should see chalk transfer evenly to the other pipe.  If you have areas where there was no chalk transfer, that's where you have a low-point or mis-match in the surface.  It may take a little bit of work with a die grinder to get it perfect...

-T

[NJT 5573]

Tim,

No 2 pipes are exactly the same. Sometimes you can get lucky and other times you have to pull the exhaust manifold, replace the gasket and studs, clamp the L pipe down and then seat and pull the manifold down. If every thing is clean, that should do it.

If you have to go that route, and a stud breaks, you need to drain the coolant below the exhaust manifolds because the studs go right into the water jackets.

If the studs break off, (easiest sometimes) they come out with a pipe wrench real easy and are not expensive at DD.

[lyndon]

Thanks, fellow Busnuts. You've given me a bit of direction and some things to try this weekend.