Yesterday I went to replace the valve cover gasket on my '87 300TD. In taking the air intake crossover pipe off, I discovered that there is a serious build up of soot in the cross-over pipe and the whole intake manifold. I scraped off as much as I could, using my shop vac and a wire brush. Unfortunately I couldn't get to the inside of the intake manifold/plenum (sp). There is a serious build up in there and I imagine the engine would run even better if that were all cleaned out. Has anyone removed the manifold and cleaned it out?

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

I took the entire intake manifold off as part of a glow plug replacement job. It was also good to replace the intake manifold gasket at the head because it appeared to be leaking.

The best I could do was scrape all I could with a gasket removal scraper, and then use degreaser and a garden hose through the sections I could not reach. I'm sure I got the majority of the buildup out of there.

This is caused by the EGR valve porting exhaust soot into the intake manifold. The intake also gets oily crankcase blowby as it is ported into the intake near the turbo. The combination of soot and oily air creates a sludge buildup. If your EGR would happen to malfunction somehow, then the soot would not be present.....



Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

I heard that!

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1995 S-350
370K + SOLD
1952 220B Cabriolet
39K kilometers + SOLD
1998 E300D
310K +
2012 E350 BlueTec
120K

you will also get less buildup with synthetic oil, as it won't coke like the dino stuff.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Yeah, the vacuum line for the EGR on my '85 300D became mysteriously plugged up shortly after I aquired it..