Continuity & Dielectric Grease

I've always wanted to ask this but the other car forum I belong to is filled with ignorance, hostility, and battles over nothing.

So, a bad ground can make you crazy, a corroded contact can cause you some grief until you track it down. Fine. So why don't we use dielectric grease on these connections? I'm sure there's a reason or we'd all be doing it.

I use it on body grounds particularly where exposed to moisture and road salt for example the front lights to the chassis rail.
Dielectric grease is actually an insulator but it protects against corrosion by excluding air and moisture but doesn't actually improve the electrical connection it just protects it. The electrical connection between the two halves of a connector is made where the high spots of the surfaces of the metal blade and socket make firm bare metal contact with nothing in between.

Although silicone grease is an insulator because it gets squeezed and scraped off the surfaces where metal to metal contact is made it has no detrimental effect on the resistance of the connection when it it is originally made and corrosion free. Where a bolted connection is used such as a main battery ground to the cylinder block the connection is normally tight enough that air and moisture are excluded and corrosion isn't much of an issue but with blade or pin connections moisture ingress is more of a problem and corrosion protection is beneficial

Thanks. I may start using it on grounds and I'm going to read up on silicone.

I am a big fan of soldering and I'm very wary of crimp connectors, though I haven't kept up if they've improved them. Done right, you can forget about corrosion with soldering.

Sometimes I do use dielectric grease! :lol: But usually only on plug wires. Even then, I've been hassled by other techs and shop owners, saying you can install a problem that way. :dry:

Generally, I figure if a ground or pin corroded, it was due to water intrusion, and dielectric grease wasn't gonna stop it. Either a connector seal failed, went missing, or had water dripping on it in such a way that the seal was never going to keep up.

Like the '12 Sonic I saw last week with coolant wicking through the electronic thermostat wire into the PCM connector. Dielectric wouldn't have prevented that issue, unfortunately.

tmcquinn wrote: I've always wanted to ask this but the other car forum I belong to is filled with ignorance, hostility, and battles over nothing.

Genuinely glad to hear you're comfortable asking this question here. Thank you!

In Europe we get Peugeots ("Pugs") and Citreons with moisture wicking into the pcm from the CTS, why they don't put a break connection between the engine loom and PCM is a mystery. The Nissan Note (which is mostly Renault) if you lift the hood in the rain a cascade of water runs over the PCM straight off the hood and windshield.

I am lucky to have a very large supply of proper lead-tin cored solder, the modern Euro approved stuff is •••• and eats the bits.