From time to time there are posts in this forum referring to dielectric grease -- several recently. Several of them suggest that its purpose and effect are misunderstood.

The term “dielectric” means that it does not conduct electricity. That means it should never be applied directly to electrical contacts.

Dielectric grease should be applied to connectors to prevent water and anything else from entering the connector and interfering with the electrical connection.

This, for example, means smearing a thin layer of dielectric grease inside the spark plug wire boots. In this application dielectric grease can help prevent spark plug wire boots from sticking to the porcelain of the spark plugs and reduce the risk of high-voltage electrical charges "leaking.". It can also be applied to the plastic parts of other electrical connectors (e.g. O2 sensor connectors) to reduce the risk of water interfering with the electrical connection.

Here's a link to one source describing dielectric grease and its use. This source is one of many easily found with an online search.

https://www.farmandfleet.com/blog/wh...%20connections.

So please, please, never apply dielectric grease to any electrical contacts. This is advice I can confirm, with my lesson learned from the school of hard knocks. A few years ago I used dielectric grease in the connectors for the upstream O2 sensors in my truck. It took many months to clear up and clean up the mess that created.

Others here are clearly better schooled than I and have better technical knowledge, and I invite them to weigh in.

 

You about covered it all! Typically its best used on rubber gasket materials in electrical connectors because it won’t cause them to swell.

 

the only place I disagree on you is the trailer wiring. I always grease those contacts otherwise they oxidize and require cleaning, usually at the worst possible time. Generally the act of plugging them in cleans away enough of the grease to allow a good contact.

 

I've used it quite a bit on electrical connectors with no ill effects. In my experience, most plugs have enough contact pressure to displace the grease and make good contact. I've had plenty of problems with corrosion on pins from moisture and none from using the grease, so I don't plan on stopping anytime soon.

 

Exactly. I've seen everyone from Army mechanics to professional repair shops as well as myself utilize it generously with no issue.

 

I'm an old Air Force "maintainer". I do the same.

 

I appreciate the replies to this thread and the testimonials of others who have used dielectric grease directly on connectors with good success.

I started this thread based on my (bad) personal experience. I've updated the original post in this thread to include a link to an online source supporting what I wrote and a little more information about my experience using dielectric grease in connectors on my truck.

I understand the idea that the act of putting together a connector will "scrape" the grease from the electrical contact surfaces and allow a good connection. It makes sense. I wish that had been my experience, but it wasn't. That said, I think dielectric grease can be used with effective results without applying it directly to the mating surfaces of connectors. YMMV.

 

I use it on all contacts that might see moisture, big squirt in the ignition wire ends, bulb sockets any connector under the hood and with Rovers literally every connector and grounding point I come across. Retired Army here and we used it as much as possible. True it won't conduct electricity but electrical connectors should make firm metal to metal contact and scrape the grease aside, if it didn't you would have a short or poor intermittent contact. It has nothing to do with any dielectric grease in a connector.

 

Correct by several accounts here.. i live where it often rains sideways... and I work on electric and internal combustion equipment for a living... indoors outbdoors... in and out of freezers (possibly the worst since they attract condensation from our humid air while being colder than outside air ... fill that connector full! If dielectric grease can cause your connections to not make contact, they were terrible connections in the first place and need to be sorted before even worrying about grease.