Does Silicone Sealant Cause Rust?

I am just now looking into that. This is a comment from another forum. And it happens to be another Mercedes forum.

"It has been mentioned previously that the use of silicone sealants on painted metal can cause rust and the recent discovery of a silicone like sealant on my car has concerned me. After some reading I have found that there are two types of silicone sealants; neutral (non-corrosive) cure silicone and acid curing silicone.

The acid curing silicone is corrosive and would etch into the paint and ultimately cause rust. This is usually designed for use on glass.

The neutral cure silicone is non-corrosive and I assume will not etch into the paint surface and should not cause rust. This is the type of silicone used for metal roofing etc. and one manufacturers website lists the uses including "Weatherproofing caravans and trucks".

So, is the use of a neutral (non-corrosive) cure silicone sealant bad for cars?"

Read some of the other comments.

https://forum.w116.org/auto-torque/silicone-sealants-and-rust/

"When I contacted a Permatex person some years ago for advice on a RTV in a non-automotive application (galvanized vent), he recommended their Ultra Black as one of their better/best RTV's for non-corrosion, adhesion, oil resistance, etc.. A peek at their product data sheet will support this."

You will have to read post number to see that the data sheet on the Permatex Ultra black has that it is non-corrosive.

From post 3: "Yes most RTV sold most places is an acetic acid cure. You can find alcohol cure RTV however, those are sometimes labeled as potting compounds. I bought Dow Corning 838(?) once from McMaster-Carr to seal up a trailer wiring connection."

From post 11: "Any automotive RTV spec'd as "Sensor Safe" is not acid cure so will be fine, including Permatex ultra blue."

https://bobistheoilguy.com/forums/threads/is-rtv-silicone-corrosive-to-painted-metal.347520/

So, I am looking at my dollar store tube of silicone sealant made by Pro Seal.

I don't see anything written that has non-corrosive or corrosive on it.

I have used 'ultra' type silicone sealant from Permatex and it smells different from the Permatex regular silicon sealant and their regular silicone sealant smells like the Pro Seal silicone sealant.

If we take Permatex's word for it the 'ultra' type Permatex is non-corrosive.

As the one post mentioned ask the maker if the product is non-corrosive or not.

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84 300D, 82 Volvo 244Gl Diesel