Warning:
Never do this with an engine low on oil, coolant, has a serious knock or known bad rod, etc, etc.

A serious issue is that long term short distance inner city driving can cause = engine to not reach operating temperature = depositing coke/carbon, and fouling the engine prechambers + valves = this is abusive commercial use = consult your owners manual for corrected service intervals.

An Italian Tune-up can help blow accumulated coke/carbon/fouling out of the engine.
Valve adjustment is called for every 15,000 miles for the generic average driver = consult your owners manual for corrected service intervals.
Valve adjustment OM617 FYI.
Valve adjustment OM615, 616, 617 FYI.



Italian Tune up
Italian Tune up

Italian Tune Up?
http://www.peachparts.com/shopforum/diesel-discussion/213854-italian-tune-up.html#post1764898

italian tuneups for gasoline engines?
http://www.peachparts.com/shopforum/tech-help/5897-italian-tuneups-gasoline-engines.html#post24335

Italian tuneup : sparks flying out of tailpipe !!!
http://www.peachparts.com/shopforum/diesel-discussion/157293-italian-tuneup-sparks-flying-out-tailpipe.html#post1204778

Italian tune-up backfired!
http://www.peachparts.com/shopforum/diesel-discussion/118360-italian-tune-up-backfired.html#post844868

Smoke on "Heavy" Acceleration - 1998 E300D-T - How Do I Clear This Up..Italian Tuneup
http://www.peachparts.com/shopforum/diesel-discussion/188815-smoke-heavy-acceleration-1998-e300d-t-how-do-i-clear-up-italian-tuneup.html#post1511377

Italian Tuneup- What's in YOUR Engine?
http://www.peachparts.com/shopforum/diesel-discussion/213482-italian-tuneup-whats-your-engine.html#post1760425

98 E300 throws Wastegate Solenoid code during italian tune up
http://www.peachparts.com/shopforum/diesel-discussion/140747-98-e300-throws-wastegate-solenoid-code-during-italian-tune-up.html#post1050640