Corrosion in the garage - salt or humidity?

[Kurtatron]

Hey everyone,

I did a compression test on my old 1991 Previa today. It did super well at ~180psi, which is really satisfying for me, since it is jdm engine with unknown miles. But I noticed that the disk brakes had a thick layer of corrosion, as well as some fasteners on the engine. That rust was not there when I parked the van for storage in a 2 car garage in November. This was before our first snow storm, so no salt exposure. So I am wondering, what may have caused this corrosion? My beater car is also parked in the garage, and brings with it salt and slush in the winter, and water after a rain storm. What do you think caused the corrosion? Salt in the air or humidity from evaporating water on the DD beater? Next time I will coat the disks with FF, and be very careful to remove the FF before driving the van.

 

[maxdustington]

It's the temp swings that cause condensation to form in an uninsulated/unheated building, especially during the spring and summer.

 

[JHZR2]

This winter we had a rainy day, and when I opened the garage, eventually all the humid air condensed on. It created quite a mess on some items.

 

[OilFilters]

A dehumidifier would help with that. They mostly don't work below 50 or so degrees, but after that it's usually not as humid. Also, a small heater would help but might cost too much to run. If you just keep it about 5-10 degrees above whatever the outside temperature is, it keeps water from condensating.

 

[demarpaint]

It is probably from condensation. On damp or very humid days I can see the moisture on my tools, and on my Jeep sitting in the garage. When that happens I partially open the door in the garage and allow air to circulate.

 

[SwampSurvivor]

Condensation. I have the same issue in my garage and I haven't put a salty vehicle in it since I've had the house.

 

[Kurtatron]

So if I don’t want to park my car outside in the winter, opening the garage door to keep condensation down would help?i can get a cheap dehumidifier off craigslist.

 

[demarpaint]

Originally Posted By: Kurtatron
So if I don’t want to park my car outside in the winter, opening the garage door to keep condensation down would help?i can get a cheap dehumidifier off craigslist.


You'd really have to stay on top of the dehumidifier or have it drain in a sink or outside. I open the door for a while or open it about 6" during the day as long as it isn't raining. If it's bad I'll run a small fan. If you have a window you can get one of those vents that you shut the window on, peg or pin the window so no one can open it and leave it at that. That should give some circulation and allow fresh air into the garage. I'd still rather keep a car in the garage, they last longer no matter what the conditions when they're garaged, especially with a little commons sense.

 

[doitmyself]

Originally Posted By: Kurtatron
So if I don’t want to park my car outside in the winter, opening the garage door to keep condensation down would help?i can get a cheap dehumidifier off craigslist.


Here in south Michigan, the problem is worst in late March through April. Anything with some mass in your garage (car, concrete floor, tool box) becomes a very cold ice cube during winter. We get those occasional warm humid days in spring and that humidity condenses on the cold masses, as stated above (dew point - just like the wetness on a glass of ice water). It's all about the humidity and temperature differential. You won't see the condensation much on a cold rainy winter day. As soon as those "cold masses" warm up in the spring, the condensation mostly subsides.

A heater in your garage would work to alleviate the condensation. There's a bunch of articles on the net: https://www.google.com/search?q=Condensa...ent=firefox-b-1

Metal roof condensation in spring - same thing happens on your rotors, etc..

 

[WyrTwister]

Light surface rust on rotors is not a big deal . It quickly wears off .

But , I live in the south west .

 

[CT8]

I wouldn't worry about the corrosion on the discs. Like magic it disappears in use. The spray coating will not.

 

[KrisZ]

Unless this Previa is meant to be preserved as a classic or something, condensation should not harm anything that is painted. The exposed metal like brake disks will not be affected.

I've been to Florida, where I'm sure there is lots of condensation due to their humid climate and yet there was absolutely no rust on any old cars I saw.