Dielectric grease, when?

So now that I have two vehicles with some level of paranormal electrical activity, it's probably time to break out the multi meter and do things right. This will have me taking apart and cleaning a bunch of connections and grounds. When do I put dielectric grease on? The package says to use it absolutely everywhere, spread it on your toast if you want. Is that true? Not the toast part, but should I be using it anywhere a connection is made?

I find it very helpful on connections that are subject to corrosion. Under the body of a car, everyone a boat, places like that. Inside the body of a car, or the engine compartment, less so.

Could be very useful depending on your climate, storage, nature of the connections, etc. Put it this way, it won't hurt anything and it's cheap.

Put it on every connector, it'll help keep crud and corrosion out.

Personally i have put it on every connection i take apart. A little goes a long way. Goes to prevent contact "fretting" which actually is a issue with newer GM cars. Cure? Di-electric.

Its a good, cheap insurance

All the time. Roger. Off to take apart doors on my truck and start chasing wires. All kinds of fun. Thanks.

Everywhere, buy a caulk tube of the stuff, pack connectors with it, put it in crimp connections before crimping, anywhere electrical contact is happening.

I've packed heat shrink connectors with the stuff. It really keeps the nasties out.

I can understand a thin layer on the outside of a connector to stop corrosion but the idea of placing a non conductive barrier between contacts just doesn't jive with me.

In reply to ditchdigger:

Its a protective grease, not a lubricant, it displaces easily under pressure. Some (probably most) 80s German cars had dielectric grease in many of the harness connectors stock.

I use it in areas prone to water intrusion. It's good to use when heat shrinking a solder splice, too: smear it on the joint, slide the heatshrink over it then hit it with a hot air gun. It keeps oxygen and moisture out.

I also use it on spark plug wire boots, keeps them from sticking to the ceramic insulator. It also works nicely on urethane suspension bushings, lets them rotate easily and gets rid of the squawk.

exactly.. the act of plugging in the connector displaces the grease

Dielectric grease is not something you want to use on the inside of connectors on newier cars... To be safe lets say around 05 and up... but some systems on earlier cars can be affected as well...

With circuit integrity tests becoming more sensitive on systems like your air bags, dielectrice grease can cause problems setting codes... Other low voltage circuits (such as O2 sensors) can start reading slightly skewed and this can cause drive ability problems..

I used to think it was ok, until I created a couple problems because of it on newier cars...

In reply to Kenny_McCormic:

I know what it is and how it does what it does but I also know that in the year I worked at getting my LME license it was highly stressed that you don't apply it to contacts/conductors, you apply it to connectors to seal them. For instance smearing it on the end of a fuse and inserting it was bad, but inserting a clean fuse and then sealing the connection with a spray of dielectric was great.

ditchdigger wrote: In reply to Kenny_McCormic: I know what it is and how it does what it does but I also know that in the year I worked at getting my LME license it was highly stressed that you don't apply it to contacts/conductors, you apply it to connectors to seal them. For instance smearing it on the end of a fuse and inserting it was bad, but inserting a clean fuse and then sealing the connection with a spray of dielectric was great.

Agreed. It also reduces the mechanical friction holding the crimped on connector onto the wire itself.

crazycanadian wrote: Dielectric grease is not something you want to use on the inside of connectors on newier cars... To be safe lets say around 05 and up... but some systems on earlier cars can be affected as well... With circuit integrity tests becoming more sensitive on systems like your air bags, dielectrice grease can cause problems setting codes... Other low voltage circuits (such as O2 sensors) can start reading slightly skewed and this can cause drive ability problems.. I used to think it was ok, until I created a couple problems because of it on newier cars...

Yeah, you don't want to take any chances on airbag circuits. The circuit test voltage is so weak it can easily be screwed up by anything on the connectors. That's why the terminals are gold plated.

Cummins diesels in some Ram trucks have a O2 circuit problem which involves replacing the harness connectors. The techs use dielectric grease because we have found some corrosion in the replaced connectors, so far none have come back.

This is all bullE36 M3.
Jesus, you're like a bunch of nattering old women, or clucking hens! .. Electrical connections are metal-metal gas tight point contacts, created by clamping pressure, at a microscopic level.
Normal metals, copper, steel, etc all have a thin surface oxide layer, that the pressure displaces. Same with silicone grease, oil, WD-40, vaseline, KY, Crisco, whatever.
The threat is not dielectric grease, it's creeping chemical intrusion at the gas-tight metal-metal joint due to oxiidation, etc. Plating with Gold, Rhoduim, Palladium, etc. helps to prevent this intrusion , since these metals do not easily react.
Packing the joint before assembly helps to encapsulate the micro level point contacts, preventing gasseous and liquid contamination that would support chemical degradation..
One of the more sensitive metal-metal joints where any such degradation causes problems is telephony.
These show up as noise on the lines, and/or high data error rates.
You will see lot's of wire wrap, and type 99 punch blocks where gas-tight jounts are formed.
But in the field, wire splices are commonly done with what are called 'mouse rubbers' or gumdrops (old Telco guys will know what I mean). The wires are inserted, and the body is criimped. Because these sometimes developed noise in high humidity locations, another type was developed that uses silicone gel filled capsules, with wire displacement connections inside.
Poke in the wires, squeeze the capsule with pliers, and voila! an encapsulated gas-tight wire joint that does not develop noise.

Anyway, there are millions, maybe billions of these joints in the field, some of them more than 50 years old.
They work, really, really, really well.

Carter

Few too many beers?