I was checking valve lash on a 6.7 Powerstroke for years before a foreman pointed out my mistake

I always set them cold, but he saw me doing it and said, 'You know the book says hot, right? You're off by a few thou.' I had the manual in my box the whole time and just never looked. How many of you guys actually run them up to temp before you adjust, or is cold okay for a quick check?

3 comments

3 Comments

the_wesley1mo ago

Learned that lesson the hard way on an old 7.3... checked them cold for ages and wondered why it always sounded a little ticky. Finally bit the bullet and did it by the book hot, and it made a real difference. Metal expands when it's warm, so that few thou really matters. Now I always get it up to temp, even if it takes longer.

the_john1mo ago

Yeah that "few thou" is everything on those old diesels. I used to shortcut it too until I saw a set of rockers that got chewed up from being set cold. The heat soak after a good drive changes more than you'd think. Now I just plan for the extra time, let it sit at idle temp for a bit, and do it right. Saves a headache later.

iris5741mo ago

Used to think cold was close enough, but checking hot on my own truck proved the book right. That small gap change makes a real difference in the sound.