Old timer told me to run high idle for 5 minutes before shutdown, been doing it backwards

My mentor Jack who worked on Cat engines since the 80s always said to let a turbo diesel idle for 5 minutes after a hard pull before killing it. I did that for 2 years religiously. Then last month I found a service bulletin from the engine manufacturer that said modern turbos with water cooling don't need that extended idle time, and actually prolonged idling can cause cylinder glazing and carbon buildup. Now I'm wondering if I did more harm than good following his advice. Who else got handed down shop wisdom that turned out to be outdated or just plain wrong?

2 comments

2 Comments

iris_stone281d ago

Jack was right for older stuff but yeah thats outdated now.

the_logan1d ago

Honestly I was in the same boat as you for years. @iris_stone28 is spot on that the older engines definitely needed that cooldown time, but I had to eat crow when I finally read the actual manual for my 6.7 Powerstroke. Ngl I spent a good year doing the 5 minute idle thing every single time before realizing I was just wasting fuel and building up soot in the oil. After I switched to just letting it idle for 30-60 seconds after a hard pull the engine actually ran cleaner and my oil analysis came back way better.