Originally Posted by Lollipop
An engine that is running rich will run cooler.
This is completely backwards. Diesels don't operate like gassers in regards to rich vs lean and the heat produced. Not calling Lollipop out, just want to let folks know when diagnosing their engine.
Also black smoke is an indication of running too rich. This can be due to too high pump tuning, washed out injector, bad or mismatched turbo, or plugged air intake. When it comes to turbos, bigger is NOT better. If not reasonably proportioned to the engine's displacement:rpm and fuel tune it won't spool properly and can result in damagingly high EGTS.
Sorry for the hi-jack, just trying to help folks understand their engine a bit more.