Weird "etching" or spots on '78 300D windows

[Phil_F_NM]

I got my 1978 300D just over a month ago and in spite of a few little headaches (rust, vacuum issues, disintegrating upholstery padding) I absolutely love the car. Love it!

I've fixed a whole host of mechanical issues and now I'm on more cosmetic stuff.

The current issue I have is that all my windows aside from the windshield have what look to be water spots on them. It is bad enough that it is noticeable but not a safety issue. It just bothers me. The side windows I don't mind with the problem but the rear window is the annoying one. During the daytime it's not bad but the spots cause a glare from headlights behind me at night.

I live in the capital of hard water so I'm used to water spots but I've never seen some that won't come off. They are relatively even across the glass and if I run my fingernail on the window, I can feel whatever it is very slightly.

I've tried to remove it with gentle scrubbing using a synthetic green scrubber sponge, soap and water, ammonia window cleaner, vinegar and now I'm out of ideas short of muriatic acid but I've got enough corrosion on the car already, I don't need a few stray drops getting under the window seal and rusting the car further.

Has anyone seen an issue of this type before on MB glass? I'm windering if it is a degraded UV coating or if, in fact, something like hard water can actually cause permanent spots? The car spent most of the last 34 years in North Carolina and the last 2 or so years here in New Mexico. I'm pretty sure it sat in some woods for a while, so perhaps it could have been sap or a tannin from pine needles?

Anyway, any ideas or help would be awesome.
Worst case scenario, I find a better window but it'll have to be one with a working defroster element.

Phil Forrest

[Mike D]

Most likely delamination of the glass. The separation of the layers of glass will/can cause a deformation of the outer shell. It usually appears as a "blotch" and then tends to spread. Do the "spots" have a blueish tinge to them almost as if they have water in them when seen in the light from inside?

[Tomguy]

If it is actually spots, there's a trick many car detailers use: 0000 steel wool. The finest stuff you can get, just rub it over the window. Use some soapy water with it if you really need to.

[Phil_F_NM]

This isn't glass separation, it's something on the surface that I can feel when running a fingernail across it.

I'll try the 0000 steel wool and let you know the results.

Phil Forrest

[pj67coll]

Another thing you might want to try doing is using a razor blade. A new one. At a very fine angle and scrape the entire surface of the window. Spray on glass cleaner then use the blade on it and clean with water and dry with towel. That might work if it is indeed some foreign matter on the outside of the window. Have a supply of blades handy though and keep changing them so they dont get blunt.

- Peter.

[mercmad6.3]

Can you see them up close with a magnifying glass? I suspect your car may have been parked near someone using a disc grinder in the past. The sparks from these will hit glass and leave microchips instantly .And when a car is showered with this it takes mere seconds to destroy all the glass surfaces. Only cure is to replace the gla$$.

[Phil_F_NM]

I can see it with the naked eye. It looks just like a hard water stain.
If it were a grinder or welding slag, only a small part of the glass would be affected as well as the metal around it, not all the windows evenly. At least, I don't think so.

One evening this week I'll try to use some 0000 steel wool or maybe a razor blade to see where it gets me.

Phil Forrest

[Phil_F_NM]

Here's an update on the spot issue. I've lived with the spots for the few months that I've had the car and they annoyed me to no end. I tried all sorts of things to remove the spots with no luck. Brillo pad, razor blade and vinegar, everything. No joy.

So today I went down to Autozone a couple miles away to recycle a pan full of old oil and pick up some clamps, CV grease, and miscellanous junk. I found this paste called Glass Scrub and asked if anyone at the store had used it but no one had. I bit the bullet and spent the $4 for a tube then came back to the house and applied the paste according to the directions then started scrubbing with a sponge. It *appeared* that it may have been working but I couldn't tell. i went to the garage and grabbed a reciprocating sander then applied the paste to a buffing pad and started polishing the window. Wouldn't you know, the stuff worked! I had thought everything like that was a gimmick. After that I took about 2 hours and buffed out all the glass on the car that had the spots. Now the original glass that was formerly spotted up enough to cause awful glare is clear as a bell. (I'm not affiliated with the producers of this product in any way whatsoever.)

Now that the glass is clear and spot-free, I'm extremely pleased. I really love my Benz.

Phil Forrest

[pj67coll]

Nice to hear something worked.

- Peter.

[mercmad6.3]

Who makes it? i might see if I can buy it in Australia.

[oldsinner111]

I use car wax and green scrubber. Then wax glass every 6 month to shed water stains.

[Phil_F_NM]

Originally Posted by mercmad6.3

Who makes it? i might see if I can buy it in Australia.

This particular product is made by a company called Glass Science, I believe. I think in my case, any good glass polishing compound would have worked.

Phil Forrest