Old-timer told me to stop using dielectric grease on cannon plugs

A senior tech at PDX back in May swore I was causing more issues by slathering dielectric grease on every connector pin. He said it attracts dust and can actually create intermittent shorts over time. Has anyone else backed off using it and just gone dry on certain harnesses?

3 comments

3 Comments

dylanbarnes3mo ago

Preach. I had a boss at a shop a few years back who caught me greasing up some cannon plugs and gave me the exact same lecture. Switched to running them dry on a few engine harnesses and haven't had a single weird glitch since. That dust and grit it grabs over time is real and it definitely messes with your readings.

miller.jason3mo ago

Wait actually though you might wanna double check that. Running cannon plugs completely dry can be just as bad depending on the environment, a little bit of dialectic grease on the threads and O-ring is still the move just keep it off the pins lol.

holly_williams1mo ago

1997 Ford F-350 I worked on last month had intermittent CEL and misfire codes that drove me nuts for two weeks. Took the cannon plugs loose and found a nice layer of dielectric grease mixed with fine grit acting like a conductive paste between the pins. Cleaned everything with contact cleaner, ran them dry, and the truck hasn't thrown a single code since. I've seen that "grabby dust" scenario way too many times, especially on trucks that see a lot of dirt roads or farm work. The grease just traps that abrasive crap right against your pins and turns into a nice little electrical highway over time. If your environment is super wet or salty I get wanting some lube, but most of us are better off running them bone dry with quality pins.