I was over-tightening injector lines for years without knowing it

I was working on a Duramax in my shop on Tuesday, putting the fuel system back together. My old boss always said 'tight is tight' and I'd crank those lines down hard. This time I used my new torque wrench set to 44 ft-lbs like the book says, and it felt way lighter than my usual muscle. The tip off was seeing a tiny crack in a line nut on an old core I had laying around. How many have I stressed like that? Anyone else have a 'book spec' moment that went against what you were taught?

3 comments

3 Comments

the_miles18d ago

Man, that's a classic shop lesson right there. I had a similar thing with lug nuts on my own truck, just cranking them until they felt right. Then I read the manual and it was way less than I thought. It makes you wonder what else we're just doing by feel that's actually wrong.

xenaf5118d ago

My old man taught me to tighten lug nuts until you hear a crack, then back off a quarter turn. Turns out that's a great way to warp rotors. I did that for years before I bought a torque wrench. It's scary how much car stuff gets passed down as gospel when it's just plain wrong. You start questioning every single thing you thought you knew.

jamie77018d ago

Yeah, the "good and tight" method got me too. Bought a cheap torque wrench and was shocked how light the proper spec felt. Now I just follow the manual and don't guess.