Wow. I've never taken an engine apart this far, and I know this is light duty for many of you. I'm digging down to get to the glow plugs, and just took the intake manifold off. Wow, lots of sludge in and around there. Even if I dropped pieces of debris in there, I'd never be able to find it. The crossover tube is equally gunked up. I'm assuming there's no reason to clean any of this out, it will just get that way within short order again, correct?

Is all this sludge the result of the egr valve?

jeff 1991 300d, 128k