TIL I'd been torquing head bolts dry for 12 years before an old timer corrected me

Had a 250k mile 6.0 Powerstroke with seeping head gaskets and a veteran mechanic asked if I lubed the threads with oil. He showed me the torque difference on his gauge and I felt like an idiot. Anybody else have a basic habit they picked up wrong from day one?

2 comments

2 Comments

the_sean2d ago

Dry or lubed, factory spec already accounts for that.

cameron7631d ago

Wait, doesn't the factory spec assume you're installing dry? Most torque values in manuals are for clean dry threads unless they say otherwise. Adding lube changes the friction, which can throw the torque off completely. I've seen guys snap bolts following a dry spec but using oil or anti-seize. If you're using lube, you usually need to back the torque down by 15-20 percent to stay safe. That's just what I've heard from old mechanics and experienced myself.