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

That's EGR for you. Someone thinks sending a car to an early grave and having to build a whole replacement car does the environment a favor.

IMO cleaning it is a thankless task. Do it because the sludge bothers you. You probably won't notice a difference in performance with a clean manifold. It's not like you can clean the valves which is where cleanliness will make the most difference.

Sixto
87 300D

It took 18 years to get to that level, cleaning it now means it will be cleaner for the next decade or two.

If you search, its an easy job to replace the turbo's vacuum actuator with a normal one. That will get rid of the computer's control over power, allow you to disable the EGR, the engine will perform better and run cleaner.

Just be glad you aren't drive an new TDI. They get clogged up on a hurry. They get so bad you can't put a pencil through the hole. I've cleaned a few of them out. It's a gooy mess. Use a shop vac to suck all the sludge out as you scrape it away. You don't want that mess going down in the the head.

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The gunk/carbon build up in the intake is just one of those diesel maintenance issues you have to deal with at some point. It is messy!......and I have done it on every diesel I have owned when they have reached higher mileage... 150K to 200K. Its like mucking out a horse stall.....your not sure if the horse appreciates it or not

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FRED

Daily Driver: 98 E300TD 199K
Hobby Car: 69 Austin Mini
Past Diesels: 84 300SD, 312K
87 300SDL, 251K
94 Chev. K-1500 6.5Ltr.TD, 373K

My guess is, it will get that dirty again, very soon. Cleaning it out will probably cause more problems than solutions. If I clean it out of the intake manifold, half the stuff will probably fall further down in. Probably best to leave it alone.

jeff