So one day I come home from work and notice two streaks on my car cover. Looks like a chemical burn or maybe just some bizarre heat source. Fast forward a few days and I'm seeing new diagonal stripes appear.

• Nothing appears to be on the car
• The bottom layer (closest to the car) is white and whatever is happening doesn't appear to affect it.
• There is nothing directly over the car. No trees are hanging over it. There are some tall trees surrounding the driveway, but not directly over head.
• The car has been kept in the driveway for years (Atlanta GA). I park in the same spot every time. I have never had an issue.
• The cover is relatively new, I have had it since March (I think).
• The car cover was pretty cheap: Gold Shield 5L - Car Cover for Mazda RX-7 1993 Coupe 2-Door

Is it a cheap car cover that is sort of decaying in a weird way? Is someone spraying something on my car (the angle is really odd)? Any guesses?

This seemingly happened overnight. Last time I drove the car was probably 2 days ago.

Here it is closer.

Closer still

2 days later, more marks are appearing

3 days later, while I was at work

 

Looks like heat or chemical eating through it.

 

vandals??

 

like the worst vandals I guess. Whatever is happening does not make it to the paint (or to the tire or wheel).

 

I'd set up a game camera pointed at your cars. Hide it relatively well and you'll be able to see if anybody is visiting your car overnight and/or while you're away...

 

Are there any windows or lawn ornaments/globes that could be focusing the sun onto that spot as it moves during the day?

 

I set up a camera the first night I spotted the "2 stripes". I haven't captured anything yet, and now there are 3rd and 4th stripes forming. It could be that someone put something on there and it is slowly eating at the cover. It has rained since though... totally saturating the cover so I would think it would wash off or dilute.

 

I looked for a crazy reflection. The neighbors did set up some Halloween stuff in the front yard which theoretically could send some light that way, but nothing lights up there at night and I checked during the day for heat without finding any.

 

My money is on some sort of reflection as well since it's linear in nature. Do you have a WiFi temperature probe for meat smoking? Could be interesting to rig that up and have it notify you of excess temps.

 

Whatever it is, I'd get it the **** off of my car before it ate through into the paint. I agree, it looks like some kind of chemical burn.

SakeBomb Garage will make you a cover that fits perfect, keeps your car dry and won't melt into your paint.

Nice Genpu MS3, by the way.

 

Thanks! I have had everything from super cheap to super expensive fitted car covers over the years. I'm sure the SakeBomb Garage cover is great, but I haven't had much luck with any cover for a car that sits outside 24/7. Weather is hard. The sun is hard. Now, this is the first time anything like has happened so maybe I went too cheap with this cover?

Update:
Haven't seen anything on camera yet. It has not seemed to get any worse after the last time, but it has been raining here for the last couple of days.

 

If someone was trying to damage your car, wouldn't they just pull the cover off and... damage your car? I don't buy the passive aggressive vandal hypothesis.

Polypropylene has a pretty low melting point. I would guess something reflective and curved like a lens is focusing sunlight on that part of the dark cover layer.

 

It looks like the sun or some sort of concentrated light is melting it? Your 4th image looks like there's some sort of light (lighter yellow spots) hitting right where that damage is.

 

Dog urine

 

I agree, some animal is lifting its leg and claiming your car as territory.

 

Polypropylene commonly used in applications where it's exposed to sulfuric acid, diesel fuel, alcohol. Is being destroyed by... doggy wee wee? WTH is that dog drinking!?

 

Yeah, since when do dogs have battery acid for ****?

 

If it was some kind of liquid like dog urine, the mark should’ve been more vertical or a big circle instead of a straight line side way at a 45° angle.

 

Well, I was thinking grizzly bear. I pretty sure they stand up to urinate on things.

 

Not sure how many Grizzly bears they have in Atlanta...

 

about as many panthers in florida lol

 

LOL... Bears! I believed the mystery has been solved. A few sunny days here in Atlanta and it looks like it is the Fall morning sun and my neighbor's odd window. I have lived at this address with my car parked in the spot for something like 13 years (so Iong I can't remember) and this has never been issue.

When I put my hand where the sun is on the attached picture, it was warm... not hot, but then again it isn't burning there either. I haven't been able to catch the light in the damaged areas but it is either this or a bear with a UTI.

Thanks for all the responses!

 

That does look pretty focused. I bet when it's in the burned spot (during the week it melted) it was really really focused. Glad you figured it out!

 

It looks like the stars (or rather - a singular star) aligned just right. You won't see it hit the same spot until the same time next year.