Not sure of best place to post this, but I've probably shortened the life of some relay contacts due to liberal use of silicone spray, oils, and grease.

I didn't know that silicone will pit and coat relay contacts due to a by-product of silicone and arcing contacts.

I found this while researching good lubricants to use to increase relay point life:

"When a source of silicone gas (silicone rubber, silicone oil, silicone coating materials and silicone filling materials etc.) is used around the relay, a silicone gas (low molecular siloxane etc.) may be produced.

The produced silicone gas may penetrate the plastic case and enter the inside of the relay. When the relay is kept and used in this condition, silicone compound may adhere to the relay contacts. The silicone compound may be changed to be an insulator which may cause the contact failure. Do not use
any sources of silicone gas around the relay."

This was in the relay user section of this Panasonic pdf:

https://www.panasonic-electric-works.com/pew/eu/downloads/ca_automotiverelay_en.pdf

With further searching I found references ( as far back as the 80's ) to silicone products reducing the life of electric motors and other places " such as windshield wiper motion control contact surfaces ".

Guessing I'll be using far less silicone products in the future.

Last year I used molykote 33 to lube my wiper gears & the wiper control contacts. Possibly a bad choice due to possible shortening of the contacts and motor life.

So definitely don't try to clean or lube electric components or contacts with silicone products.

I've found a few products that are supposed to improve relay contact life but haven't chosen one to use yet. A few tout increasing relay contact point life and function way beyond normal non-lubricated contacts.

Contact point life is greatest with NO coating whatsoever. The entire point of the contact points is to make a solid connection. Any substance is going to increase resistance, not decrease it.

Sliding contacts can be lubricated with dielectric grease specifically made for electrical connections. Anything else should be DRY.

If you use silicone or grease around anything and you're concerned about it, clean the points with acetone and a clean cotton rag or Q-tip.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I haven't spent enough time to come to a final decision, but my initial research seems to indicate a proper lubricant can be expected to increase contact life.

A few sites have info:

https://www.nyelubricants.com/stuff/contentmgr/files/0/8872a6eb9c4f51b0f519af73d9cabe7f/en/factsandmyths___lubricating_electrical_connectors_final.pdf

https://www.electrolube.com/pdf/contact-lubricants-brochure-electrolube.pdf

Another relay manufacturer TE had this comment: Silicone
Materials containing silicone or its derivatives must not be used in any form
in or near to processing and packaging of subcomponents and the final
relay assembly. Silicone and its derivatives are not allowed in the material of
any component in the vicinity of the relays.
Silicone atmosphere can diffuse through the relay housing and cause contact
failures, siliceous compound deposits can create an insulating abrasive
layer on the contact surface.
Contamination can occur with all silicone-based materials before and after
cure (contain silicone volatiles), silicone aerosols, silicone fluids, grease and
hand cream, etc..
Some types of signal relays are suited for application in Silicone environment,
howeve

Relay contacts last the longest when sized correctly for the task at hand and when made of the proper material for the type of current (AC, DC, high current, low current). Adding ANYTHING to the contact material will shorten the life and inhibit current flow. Do not grease your relay contacts.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Silicone products were banned from many installations where many relay contacts existed - such as old style electro-mechanical telephone exchanges.
Even the fumes from floor cleaning products could place a small covering over relay contacts.
Don't use any covering material on relay contacts.
There's a risk of sparking which causes Ozone. The Ozone residue is black carbon

I haven't formed an opinion yet, so I'm still researching it. My comfort module with the eight mounted relays is my main concern. I plan to replace the relays sometime in the next few months. I'd like for them to have the longest life possible.

This link provides more information on the lubrication of contacts:

https://www.machinedesign.com/archive/lubricating-electrical-switches

That article is for SLIDING contacts. Very different animal to POINT contacts like a relay. Don't lube the points. Seriously, just don't. Buy relays with points rated for 28VDC or higher, they have a special alloy designed to resist ablation and oxidation. AC-rated relays will burn up quickly in DC applications. Do not put ANYTHING on the points, you'll reduce their life considerably and probably notice intermittent operation immediately.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

So far my reading indicates a "properly selected" lubricant can improve the reliability of contact points. No final decision yet til I research it more.

This spray cleaner & "lubricant" has many positive reviews ( I liked the one about the old Jaguar ):

https://express.google.com/u/0/product/3761289377251508578_1168012930616250541_6136318?mall=Nevada&directCheckout=1&utm_source=google_shopping&utm_medium=product_ads&utm_campaign=gsx&utm_content=control_0_30

Same company but mentions relay contacts:



more info on same company's products:

https://system.na3.netsuite.com/core/media/media.nl?id=11663&c=ACCT113328&h=9d49b3a2fcecd1caeefb&_xt=.pdf

I understand that silicone can wreck a MAF. I never use silicone spray under the hood.
Anziani
'97 CL600 66K

The bottom two pages of the last link have pretty much convinced me to try the Caig Deoxit products. Could be wrong but I believe the product will help keep the electrical connections working better.

Deoxit is for an already damaged contact or small-signal applications where noise is a concern. You are dealing with a POWER relay. Don't lube the contacts. Quit overthinking things and try listening to someone who actually has experience with these things. You're dealing with a point that needs to carry several amps of DC current. Anything you put on the point is going to degrade its ability to carry current and accelerate wear, ablation, oxidation, and failure of the point. With over 20 years of experience dealing with DC power relays, I can say with extreme confidence that the best substance to prolong life of a relay point is NOTHING. Rate it properly for the load and it will last for decades maintenance-free. Add some foreign substance and you'll get a couple years of intermittent or unreliable operation tops.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Well said, Diseasel300!
Anziani
'97 CL600 66k

Diseasal300,

After a lot of reading, I'm agreeing with you and also with a few relay manufacturers. Also one comment from a NASA article. Most comments about relay contact enhancement were from the few manufacturers that manufacture relay contact enhancement products.

I did find quite a few comments of another product 'Stabilant 22 or 22a' for non-arcing contacts. So instead of silicon for I'll be using Deoxit and Stabilant for electrical connections, and nothing on relay contacts.

DeOxit makes a great contact grease L260NP that works very well in switches and plugs. It's designed for electrical connections and keeps the silver plating from tarnishing and making poor connections. Just don't use it on relay contacts.

We've used the L260NP for years in our equipment with 0 issues. I've used it in my own car to lubricate switches, ground points, and various plugs and connectors, also with 0 issues.

Relay contacts can be cleaned with Acetone and a Q-tip, but don't put anything else on them. They need to be as dry and clean as possible for longest life.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Relay points are made of tungsten and are very corrosion resistant. Clean and dry is the way to go. You can only lose by lubricating them.



Silicone spray will also make is MUCH harder to paint your car. Wherever it's had a chance to soak in to an old finish, you will end up with fisheye when you recoat.