Soot from Vent on Turbo Heat Shield

[Bluespanner]

I have a slight lack of acceleration and power from a recently bought 1996(N) 2WD 2.5TD. With the engine exposed and looking from the passenger side. The right hand side of the heat shield that covers the turbo has soot around one of the vents in the shield. There's a slight hiss as well when I'm driving. Not loud at all, but it's definitely there. I know there's a lack of power as I owned the same model Bongo for 12yrs and the lack of pull when you put your foot down is noticeable. There are no signs of any head problems, no milky deposits, oil in water etc. I've fitted a low coolant alarm and a engine temperature alarm and all looks good. I'm assuming this is turbo gasket or a sheared exhaust manifold bolt. I'm not near a bongo friendly garage, so if it is either of the mentioned faults is this something a competent garage can deal with, is this another best done at a bongo specailist garage. If anyone has any other ideas as to the origin of the symptoms and the soot I would be very grateful to hear.

Thanks in advance

[Billybongo123]

Either one of the manifold gaskets is leaking, or the mani is cracked. That leak will cause the turbo to lose efficiency and spool later also. Trace the leak. Marc