Grease for fuses/relays?

[wallyuwl]

I just changed out a relay (the one I took out was original to the vehicle). I noticed the one that I took out had some grease on it. I put the new one on without any grease (well, a small amount, as much as I could take off the old one with my finger and put onto the new one).

My question: is grease helpful and/or necessary to put on relays/fuses? If it is helpful, what type of grease, and where can you buy it (ideally at a parts store)?

 

[440Magnum]

If the fuse or relay is in a location prone to corrosion, a dab of silicone dielectric grease (available in the electrical section of most parts stores) is a good idea. I don't really like to use it in dry locations because after all, its an insulator. But the idea is that the contacts press thru the grease, and the grease then seals out corrosion.

This is the stuff I generally use. Its the same stuff used on spark plugs, coil towers, and distributor caps:
http://www.amazon.com/Permatex-PERMATEX-DIELECTRIC-GREASE-22058/dp/B002KR5YN4

 

[bepperb]

Yes. Dielectric is what you should use. I use sil-glyde which is absolutely not specd for this application but works well IMO.

 

[AMC]

Regular white lithium grease can be used as a di-eletcric grease too! Works great on battery terminals because of how long it lasts.

 

[George7941]

I screwed up the relays on my truck because, when the truck was new, I applied dielectric grease to the relay sockets in the underhood fuse/relay centre in the truck. Electrical corrosion is a problem in the salt belt where I live.

My relays started failing one after another. That is when I noticed that the Delco relays were not sealed, the plastic relay covers just slip over the relay base plate. The grease was getting on to the contacts. So, I took all the relays apart, sprayed with degreaser and blew them clean with compressed air. I even sanded the contacts. I cleaned off as much grease as I could from the sockets.

Fast forward six months and the relays started failing again. The Delco relays were around $10 each, so I used these instead.
http://www.delcity.net/store/With-Resistor-!-Miniature/p_791799.a_1
These relays are only a couple of bucks each, are sealed, and, from my experience so far, high quality.

The relay is 5 pin, so just snip off the centre pin for 4 pin applications.

Just last week, I applied Stabilant to all the relay and fuse sockets in the underhood fuse/relay centre.
http://www.stabilant.com/
It does not affect the contacts if Stabilant gets on to it, not that it is an issue with sealed relays.

A friend of mine has a Ural motorcycle/sidecar combo and he came to me with electrical problems. I traced the problems to contaminated relay contacts. The dealer had applied grease to the relay sockets on his bike during routine servicing. I replaced his relays.

Moral of my long story --- DO NOT APPLY GREASE TO RELAY SOCKETS if the relays are not sealed. Use Stabilant instead.

PS Why doesn't pasting the Delcity URL not make it a link?
Just search for product #791799 at http://www.delcity.net/

 

[wallyuwl]

The location is inside the car, under the passenger dash and above the glove box. So probably not even necessary because of its location.

I did a search of the forum before posting my question and several people were saying that dielectric grease made their relays go bad in short order. Any other types of grease? There were one or two I saw (don't remember the names now) and at the time I did an internet search and they seem pretty hard to get.

Edit: George posted his while I was typing mine about the dielectric grease messing things up.

 

[cchase]

Dielectric grease is probably clogging up the contacts inside the relay. If that's the case, there's really nothing you're going to be able to put inside a relay that won't affect its operation.

I don't see how applying dielectric grease to the external contact points would ever cause a failure, however.

 

[440Magnum]

Originally Posted By: wallyuwl
The location is inside the car, under the passenger dash and above the glove box. So probably not even necessary because of its location.

I did a search of the forum before posting my question and several people were saying that dielectric grease made their relays go bad in short order. Any other types of grease? There were one or two I saw (don't remember the names now) and at the time I did an internet search and they seem pretty hard to get.

Edit: George posted his while I was typing mine about the dielectric grease messing things up.


If dielectric grease causes a problem, then pretty much ANY other grease would be even worse. Leave it off when in doubt.

 

[George7941]

Originally Posted By: cchase

I don't see how applying dielectric grease to the external contact points would ever cause a failure, however.


I did not see how either and that is why I applied the dielectric grease in the first place. Especially since the relays are mounted right side up and the grease has to migrate upwards.

I still have four of the original GM relays, in non-critical applications, like DRL, Washer, Lights etc. I have a spare relay in the glove box to replace any that might fail on me.

When I first started having problems with the relays, I opened them up and noticed it was a little slimy inside. I don't know how the grease migrates to the insides of the relays. Perhaps it creeps up the relay terminals. Or maybe some vaporisation is taking place and then condensation inside the relay case. Silicone greases are heat-resistant, so it is definitely not the grease boiling fron underhood heat.

In the case of the Ural, the relays were mounted sideways and the grease still made it inside. Don't ask me how it makes it inside, I just know it does.

FWIW, I used Grote dielectric grease. This stuff is really tacky and stays put where you apply it. I used to use Dow-Corning dielectric grease but it does not adhere well to surfaces

http://grote.com/cgi-bin/goc/goc.cgi?product_number=99170

The grease on the Ural looked like white lithium grease.

 

[mechtech2]

Originally Posted By: 440Magnum
If the fuse or relay is in a location prone to corrosion, a dab of silicone dielectric grease (available in the electrical section of most parts stores) is a good idea. I don't really like to use it in dry locations because after all, its an insulator. But the idea is that the contacts press thru the grease, and the grease then seals out corrosion.

This is the stuff I generally use. Its the same stuff used on spark plugs, coil towers, and distributor caps:
http://www.amazon.com/Permatex-PERMATEX-DIELECTRIC-GREASE-22058/dp/B002KR5YN4


Good advice.
This is also why I don't grease battery terminals and cable ends INSIDE. Who wants an insulator there??
I put grease outside, but preferable a few light coats of Rustoleum spray paint.

An option for fuses and relays is to simply keep an eye on them and clean things every 6 months or so.
I prefer using a shielding grease under the hood, or anywhere ambient stuff can corrode things .

 

[paulo57509]

During the course of replacing the ignition lock cylinder in my Legend, I noticed the combination switch (headlight/wiper/tun signal stalks) clock spring (I think that's the common term for it) under the steering wheel was packed with grease.

It got me thinking, is there a correct grease for applications like this? It cannot attack plastics, must not inhibit electrical conductivity, cannot get runny in elevated temps, etc....

Now I use this instead of Vaseline.

http://www.lubriplate.com/products/greases/ds-es-electric-switch-lubricant.html

 

[Vikas]

Conductive grease is not conductive enough! Do not use it where it is not specifically asked for. The job of dielectric grease is to prevent corrosion. It is NOT there to pass electricity. Grease is used to displace air which is around the contact point(s). Air is not a conductor and the grease does not need to be conductor. The clamping force at the contact point will displace the grease where the electron needs to "move".

Unfortunately, this misconception is very hard to get over for a non engineer.

- Vikas