Dielectric Grease

[NCGuy68]

In the electrical world, a material that is dielectric does not conduct electricity. Yet many 'tech' manuals say to apply dielectric grease to electrical connectors.

Why put nonconductive grease on a electric connection that we all know should be clean and tight?

 

[onion]

The grease helps keep water out, prevent corrosion, etc. And you'll definitely want it to be dielectric because you often have multiple wires within the same connector. If that grease that you've just wiped on the pins is conductive, then you could potentially have 'shorts' between pins. And I can state from experience that partial shorts between pins in a connector(usually from wet and/or corroded pins) are bad medicine.

 

[brianl703]

When you plug an electrical connector together, the grease is pushed out of the way so that the terminals touch. So the fact that it's an insulator doesn't cause problems.

 

[Merkava_4]

To add to the above posts, another reason you want your grease to be non-conductive is because you don't want to cause a short to ground.

Back in the old days, we used to apply the silicone grease to the cam on a breaker point distributor. Now the grease is used inside spark plug wire boots to keep them from becoming permanently attached to the spark plugs.

On a side note: I buy the Dow Corning 111 (that's one-eleven) silicone grease in a much larger tube than what you would get from an auto parts store. I use it for both an O-ring lubricant as well as a dielectric grease. Just last week, I used some for a brake calliper pin lubricant.

You can get all of the different Dow Corning lubes from Motion Industries.

 

[mechtech2]

ditto onion

 

[obbop]

Can dielectric grease be used on rubber components such as seals around door windows to assist in preventing stuck windows during frigid weather?

 

[brianl703]

Yes, in fact I've used it for that AND for squeak elimination. I use a paper towel to rub it in.

 

[Kestas]

It looks like the Dow Corning 111 grease has silica thickener. Though the thickener makes it a good lubricant, I would prefer to use silicone with no thickener for electrical contacts, like the Dow Corning silicone vacuum grease. The thickener is made of very fine particles, and these particles may provide a finite gap for the contact.

 

[Lonnie]

I've always wondered if Pledge Furniture polish on car batteries acted as a dielectric. When sprayed on a battery to clean it up and re-applied a couple of time a year, you end up with a battery that looks as new until the day it dies. There will be no corrosion or stains at all.

 

[brianl703]

Ford sells a tube of electrical terminal grease that is Nyogel 760G. I use this instead of silicone grease for electrical terminals. Apparently Nyogel is somehow better for that purpose--it does appear to be a little thinner. It's transparent but glows blue under a UV light.

Years ago they used to use a white grease for terminals which I think is lithium grease.

Delphi claims that their metri-pack and weather-pack connectors need no grease at all, and in fact I haven't seen any factory-applied grease on ANY connectors in vehicles made in the last 10 years that I've looked at. (Ford Escort, Dodge Caravan, Saab 93, Chevrolet Malibu Classic, Ford Escape)

Apparently all the connector manufacturers think the connector seals are enough protection against water/corrosion.

 

[obbop]

Gotcha' on the grease on rubbery stuff is groovy.

Likely a little dab'll do yah.

 

[NCGuy68]

Quote:

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When you plug an electrical connector together, the grease is pushed out of the way so that the terminals touch. So the fact that it's an insulator doesn't cause problems.

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Why not just plug the connection together clean and then coat it with the dielectric grease? That way you know you have a clean and tight electrical connection.

 

[brianl703]

In many cases the design of the connector is such that is not possible. This is particularly true for multi-way connectors. You could try coating them with grease after you plug them together but I think that'd just result in a mess and wouldn't likely keep water out very well.

 

[Merkava_4]

Quote:

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It looks like the Dow Corning 111 grease has silica thickener. Though the thickener makes it a good lubricant, I would prefer to use silicone with no thickener for electrical contacts, like the Dow Corning silicone vacuum grease. The thickener is made of very fine particles, and these particles may provide a finite gap for the contact.

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Kestas,

As long as you buy some kind of Dow Corning product I'll be happy.

 

[Master ACiD]

most greases and oils are dielectric. i have seen guys submerge their computers in baby oil and motor oil. if that doesnt short out something like a computer its not going to short out a connector on a car.

you guys could save some money on those expensive purpose built dielectric greases and just use some low quality wheel bearing grease. it works great on my connectors on my car. dont see why it wouldnt work on anyone elses.

 

[punisher]

Problem is petroleum based greases can react with plastic (or the rubber gaskets in the connector), either weakening it, or causing it to swell. I still have a tube of Ford silicone grease left over from my shop days that gets used on caliper pins, AC orings and electrical connections.

 

[Kestas]

Quote:

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Kestas, As long as you buy some kind of Dow Corning product I'll be happy.

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Okay, as long as you buy SKF product.

 

[Merkava_4]

Quote:

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you guys could save some money on those expensive purpose built dielectric greases and just use some low quality wheel bearing grease.

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As the valley girl would say: "gross me out, gag me with a spoon!"

Master ACiD, I hope you're not talking about that nasty dark grey wheel bearing grease.

I got my 5.3 ounce tube of Dow Corning 111 for about $12. It's about the size of a large toothpaste tube. The stuff goes a long ways too because very little is needed at a time; especially for O-rings. And the stuff has such a high viscosity, that once it's on there, it doesn't come off unless you purposely wipe it off. Good stuff made in the USA.

 

[porcupine73]

I bought this stuff some time back from McMaster.com, but it I believe it has a fair amount of thickener.