Am I the only one who sees guys torquing head bolts dry?

I was helping a buddy in his shop in Boise last month, and he was putting a head back on a Duramax. He just slapped the bolts in and started cranking. I had to stop him. You absolutely must use the right lube on the threads and under the washers, every single time. The torque spec in the book is based on a specific friction coefficient you only get with the factory lube or a proper substitute. Doing it dry gives you a false torque reading and can lead to uneven clamping force or a blown head gasket down the road. I learned this the hard way on a 6.7 Powerstroke about five years ago. I had to pull the head twice in six months before an old timer at the parts counter set me straight. What specific lube do you all use when the factory stuff isn't available?

2 comments

2 Comments

daniel5115h ago

My uncle ran a diesel shop in Spokane for 30 years. He always used a thin coat of straight 30-weight oil on head bolts and never had a comeback. The key is being consistent so the clamping force is even. I've done it that way on dozens of motors without issue.

the_mia3h ago

That makes sense about consistency being the key. Using the same thing every time probably matters more than what you pick. Your uncle's track record speaks for itself.