From Sprinter-rv.com


“Black Death” – The most serious possible problem is injector leakage, a.k.a the “black death”. The fuel injector hold-down bolts may get loose or the seals erode, and the injector seals may begin to leak, producing black goo (“coking”) in the injector compartment on top of the cylinder head. Despite the name, this problem does not mean the “death” of the Sprinter, but it can be a major repair, depending on how far it has progressed. To check for this, remove the 5mm Allen bolts securing the plastic valve cover and inspect the injector compartment for leaks.

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Brian
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