Mildew (?) on white paint, how to correct

[tonymac]

Hello folks. I am a very green behind the ears detailing enthusiast hoping for some help on how to handle this situation.

The situation is with the water gutters on a 2016 F150. There is what I believe to be mildew stains as well as paint failing/cracking. Focusing on the stain, so far what I've tried is using Meg's APC (diluted 4:1) with a detailing brush as well as a clay bar/lube. The markings only improved marginally; barely enough to make a difference really and before I go too far and mess this up more, I was hoping some of you pro's could chime in.



71543

If it's a lost cause, what do you think about adding some 3m weather stripping on top and calling it a day? Or maybe vinyl wrapping the entire roof? I'm open to all ideas and advice (not a "customer" vehicle).

Also I wanted to mention that I did try to search but came up short for anything like this.

Thank you guys in advance, I've been lurking here for a while and this community is such an amazing resource.

[muaddba]

I am not sure how this would not be a warranty issue, unless you have a crap-ton of miles on it?

[tonymac]

I am not sure how this would not be a warranty issue, unless you have a crap-ton of miles on it?

It's a 2016, we are past warranty days.

[muaddba]

Yeah, my bad there, I was thinking of the outer body rust warranties. The first thing you need to do is find out just how bad that paint failure really is, is it down to primer or is it down to the metal? Either way you will need to seal up the edges of the failure area in order to prevent infiltration of contaminants (including air and water) which could cause it to continue to deteriorate and expand the failed area. While they do make weatherstripping, etc that can go in there, I would talk to a good body shop nearby. A repaint of the roof isn't going to be cheap but it shouldn't be exhorbitant either, and if considered over the lifetime of the vehicle it will be well worth it. Then protect it well, and you should be all set.

[2black1s]

First of all, I doubt that what your dealing with is actually mildew. It may be but I doubt it. But... If it is try some bleach (clorox). That will kill it. Be sure to do a small test spot first to see the results.

Follow that by scrubbing the affected area using a toothbrush with a mild polish, paint cleaner, or AIO.

I really think what you're dealing with is simply stained paint (and that really shows on white). The toothbrush method should remove the stains if that is in fact the case.

[tonymac]

First of all, I doubt that what your dealing with is actually mildew. It may be but I doubt it. But... If it is try some bleach (clorox). That will kill it. Be sure to do a small test spot first to see the results.

Follow that by scrubbing the affected area using a toothbrush with a mild polish, paint cleaner, or AIO.

I really think what you're dealing with is simply stained paint (and that really shows on white). The toothbrush method should remove the stains if that is in fact the case.

I thought it might also be a residue left behind by an aftermarket molding or something to that affect and so I tried a little citrus degreaser as well as some goof-off on some test areas and after they did nothing, I then tried some bug and tar remover; the black stain doesn't seem to be going anywhere although it is feeling smoother to the touch. I'll try an AIO next time I can, ty.

[Mike Hoekstra]

I pulled the picture and tried to blow it up for a better visual of what I'm looking at but it didn't show me much. Can you give us some conditions for the vehicle? i.e. Does it sit outside all the time? Is it garage kept? Where do you live/weather conditions - humid, dry, etc. Are there trees near by? Is this condition anywhere else on the vehicle besides the drip channels? How long has this been allowed to sit? This couldn't have happened overnight.

If you are 100% positive it's mildew, try this product available through Autogeek by Marine 31 Marine 31 Mildew Remover, boat mildew remover, marine mildew cleaner, how to remove mildew from boat seat cushions (https://www.autogeek.net/best-boat-mildew-cleaner.html)

If it's something else, I always start simple and work my way up - glass cleaner will fix a lot on the outside of a vehicle, then an APC, a cleaner/degreaser, tar remover, etc. etc.. You said you had tried clay with some success, move up a clay grade to something aggressive like Meguiar's aggressive clay, Gyeon, Blackfire, etc. there are several options available.

[tonymac]

I pulled the picture and tried to blow it up for a better visual of what I'm looking at but it didn't show me much. Can you give us some conditions for the vehicle? i.e. Does it sit outside all the time? Is it garage kept? Where do you live/weather conditions - humid, dry, etc. Are there trees near by? Is this condition anywhere else on the vehicle besides the drip channels? How long has this been allowed to sit? This couldn't have happened overnight.

If you are 100% positive it's mildew, try this product available through Autogeek by Marine 31 Marine 31 Mildew Remover, boat mildew remover, marine mildew cleaner, how to remove mildew from boat seat cushions (https://www.autogeek.net/best-boat-mildew-cleaner.html)

If it's something else, I always start simple and work my way up - glass cleaner will fix a lot on the outside of a vehicle, then an APC, a cleaner/degreaser, tar remover, etc. etc.. You said you had tried clay with some success, move up a clay grade to something aggressive like Meguiar's aggressive clay, Gyeon, Blackfire, etc. there are several options available.

Vehicle was purchased used so the origin is more or less unknown. It went unnoticed at time of purchase - you can really only see it looking from the top down which is how it was first spotted (looking out from the 2nd floor). We're in FL which is also where the vehicle originated. These are the only spots on the vehicle with this condition, that's why I'm thinking the previous owner had some aftermarket kind of strip installed and at some point while trading hands, it was removed. You are right, I don't think it happened overnight either; I'm thinking it's been holding water for years, never actually being allowed to drain properly. I am not at all positive what it is though haha I'm doing my best with my limited knowledge. Thanks man, I will take your advice into consideration as well and report back next time I work on this thing.

[Ed Abbondanzio]

I've seen this (or something very similar) on vehicles that have sat under a tree for a long period of time. Although usually the whole roof will look like that.

It almost seems like someone cleaned it previously and the stuff on the seam sealer was left behind as it's (typically) harder to remove.

I've had luck using a strong degreaser and a small brush to remove some of that stuff but often times I've found there's sometimes missing paint beneath those black specks and you'll see little yellow spots of the seam sealer popping through.

Hopefully someone with more experience than me will chime in.

[DUBL0WS6]

I use a strong cleaner like Dawn or an All Purpose Cleaner and see what happens.

[Thomkirby]

Correct me if I am guess incorrectly, but your 2016 F150 is the aluminum cab. My 2018 F150 has similar material in that body weld section. Look at other F150s and you should see the same material. It in most cases is not perfectly smooth as your is showing some irregular surfaces.

Your photo to help is the top of the truck and that zone is where the body is bonded together (in your rain gutter).

Most likely this truck spent it's life out in the open air under a tree and those black spots are stained. If it is aluminum cab it is not going to rust.

You might want to use the toothbrush and some mildew remover as Spikey Mike suggested. I would not be too concerned about marring the paint in that channel but if so you will have a bigger job to polish in that rough area.

Oh well at least it is on the top and out of sight.