I have a different comment.

Since I had giving the Silicone Sealant advice the Hardware stores are selling a Black Spray Sealant that is rubbery.

I don't know what type of heat that stuff can take but one of the uses for it is on Roofs.

I bought some in the Paint Department from Home depot and used it on My Motor Home Roof.

I also ask a question a long time ago if Auto Tire Paint would work. But, apparently no one has ever tried that.

If you spray Brake Cleaner on the Rubber be sure to give it at least 15 minutes to dry as it may get absorbed into the Rubber a bit.

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84 300D, 82 Volvo 244Gl Diesel