Torque adjustment when using thread locker

[stevetone]

Correct me if I'm wrong, but I think I've heard that one should adjust the torque specification for bolts that are not "dry" (i.e., they have anti-sieze or thread locker on 'em). If that's true, how much should the torque be reduced?

 

This question is in anticipation of using Loc-Tite Blue on oil pump screws and the crank pulley during my timing belt replacement job.

 

Thanks for your input!

 

Steve

[porcupine73]

Hi. Typically reduce by 1/3 for antisieze or threadlock is what I hear. Esp for smaller fasteners going into aluminum which kind strip somewhat easily.

 

Note that you must know what the torque spec is for. Typically unless it's stated otherwise, the torque is for clean dry threads as you stated.

 

However some fasteners such as the crank pulley bolt are for oiled threads. So in that case I would not reduce the torque. It is not uncommon to hear of that bolt especially coming loose later.

 

On the oil pump screws you could even go red threadlock. I mean the only reason you would ever remove those screws later would be to check the rotor clearances or to replace the rotor pair; in those cases people usally just replace the whole pump.

 

When I tried to get the screws out of my oil pump's rear case, a few were already loose, a couple were tight but I could get them out, and one I stripped (whoops) and those are weird screws you won't find at the hardware store. I used green thread lock (the wicking kind) on the new pump screws; it soaks down in there so you don't have to remove the fastener to apply it.