[AZMT123]

My W140 has essentially a perfect original paint job,silver color, and the car is stored in my garage most of the time.
When I went in to check it this week, I saw what I thought was moisture condensation on random areas of each side of the car, not the top, hood or trunk. However it was not moisture, but rather a silvery material in streaks, with some adherence to the paint. I could gently wipe it off and the underlying paint surface was normal. I checked the roof for leaks above these areas, as we have had a lot of snow here in the NW recently, and then a rapid thaw and melt.The roof was fine. However I note that the cement floor has white deposits, and these are termed "Efflorescence" literally meaning a "flowering" or emergence of alkali salts from the concrete, which come to the surface with moisture, the moisture evaporates, and the salts are left behind.

The garage is beside a road that was heavy with snow, now all melted, so that could be the source of the moisture.
I have never seen this before and the car has been stored for years in this garage with no such deposits.

Any ideas of this or other causes? I am going to gently wash the car to remove them, but again I see no evidence of paint damage.

 

[plinker17722]

Caused by damp and cold that change to patches of condensation then to efflorescence..
Used to get it on our wall in the bedroom of mobile home [caravan] wont harm your paint work ..i would get an indoor car cover to put on in cold weather

 

[AZMT123]

Thanks for your response! It makes sense. I have a car cover and just haven't used it, so now I will

 

[plinker17722]

AZMIT123 And the cover might mark the paint Paint hardens quick and i dont think cotton sheets iwould hurt it . What about a small heater, just to lift the temperature up a little ? But better still a de humidifier i used one in my caravan to clear all the condensation away and it sends out warmer air after .

 

[AZMT123]

Just to update, I washed the involved areas with car soap and rinsed off after a soak, and everything came off. Interestingly, apart from the white haze deposits there were small black grain like deposits in some areas that were more stuck on and they did come off without scratching, but it really looks like maybe some of the concrete floor vaporized in the cold and damp somehow and then deposited on the car. Paint looks perfect. My car cover is soft so as long as the car is clean first I think safe to use, but I agree need to bring the temp in the garage up a bit, it actually feels colder than outside. I think the concrete floor acts like a cold sink. Some day I would like a "dream garage" with heat and even a fridge

 

[plinker17722]

Your lucky mine sits out side every day .. My other half took charge of the garage when we moved in .At the time i did not have a car . But after i purchased the W124 i use a fully waterproof car cover for the winter . The cover is better than nothing , and it stops rain water entering nooks and cranys .The engine is packed up all around inside the hood with warm items . She is warmer than i am in bed lol ..