puzzled over stained headliners

[Imperial Aspirant]

In browsing around for fuselage cars, I've noticed several with headliner stains, ranging from mild to oh-my-god.

In fooling around with other old cars, I've encountered plenty of falling-down headliners (looking at you, GM!), but really not any issues with stains. I don't know how they get up there, unless there's some kind of leak that lets rainwater in. (BTW, none of these cars have had sunroofs.) Attached is a couple of screengrabs from a blurry video, but I think you can see what I mean.

Is there a known issue with these models that causes this?

[ImperialAtom]

It has to be water related. Maybe there is seam or something in the body where it was welded together during manufacture and it's not water-tight. Or no longer water-tight after all these years of flexing and twisting.

[DetMatt1]

Or mice got up in there at some point but that’s usually accompanied by a foul smell.

[Crown64]

Cadillac had a similar problem in the 1967-1970 models. It was because of a chemical reaction between the headlining and the inner roof insulation (and the glue used to retain it). When a Cadillac so affected (or should I say, afflicted) presented this problem during warranty, the fix was to replace the headlining, and to trim away any discolored roof insulation and/or prevent it from contacting the back side of the headlining material. Based upon this , I surmise that the roof insulation has fallen free of the roof panel, and is contacting the back side of the headlining, causing the discoloration. I haven't seen one as bad as the one in the photos, though.

[Imperial Aspirant]

Interesting, Crown64. I have not had a Caddy that old, so I had never heard of this. The headliner in my '78 looked great as it was falling down.

If I decide to pursue the car in the pix, I'll have an indepth discussion with the owner about this.

[ImperialAtom]

Interesting indeed - will have to keep that in mind. To be sure, you might try the sniff test - if it smells like mildew or something in that spot but not in others, then I would assume it's moisture related. Don't sniff in any black mold though

[Imperial Aspirant]

I'm happy to say that mold huffing has not been one of my real temptations--so far, anyway.