I was watching a show on TV, specifically diesel and in this series they were showing heavy commercial diesel engines being built. The final step for all of these engines was to spray paint them. It looks like all they did was cover the fuel openings with plastic caps and then they sprayed down everything. I know this isn't really related to MBZ's, but I am a diesel fan and thought my fellow MBZ gurus might know?
I figured my 300D would look nice with a purple engine...NOT!!!!!!

I don't know for sure, but I do have some theories. One is the obvious reason, cosmetics. You know "Chevy orange", "Ford blue" etc. It may be that since diesel eng. blocks are cast iron, they paint them to keep that "new" look, instead of the rust look. Personally, I like the industrial machine look of my engine and the related components.

Perhaps, but they painted everything, wires, niuts, fuel lines etc. Maybe if everything is painted, they could identify a fuel leak or if ever a component was ever replaced.

Paint on the outside of an engine is for rust prevention and looks. The engines I've built, I've also painted the inside of the block. Why you might ask? Two reasons. 1) paint on the inside surface of the block allows the oil to drain back faster. Not so important on a street engine, but critical when you're pulling 8 grand up a hill climb...you don't want your sump to run out of oil. 2) the paint also helps seal the misc grains of sand that might be still present from the casting process. Of course you keep the paint out of the bearing and cylinder area as well as any of the oil passages. I used General Electric Glyptol, which is a paint designed for the inside of power generators. Thinned down abit and it really sticks well to a properly preped block.

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Dakota, which one do you use for the 8K RPM hillclimbs, Emma or Josephine? I would love to see a MBZ at Glamis! A little levity to brighten the day--have a great one.

Old Blu
 

No, neither Emma nor Josephine was a gleam in my eye at the time. :) Was into Small Blocks and 4WDs back then and my baby was a 71 Blazer with tricked-out-everything. Still running strong after 350,000 miles....many of them offroad in the Black Hills, the Badlands and the Canyonlands. Have never been to Glamis, though, but I bet the dunes are awsome.

Don't forget that paints primary function is corrosion prevention, it's secondary function is esthetics.

Have a great day,