Mysterious Windshield Condensation

[WolfeMan]

So here's a new one.

I park my car in a garage, it's bone dry every morning.

I start it up, and drive to work. About 3 minutes into the trip I start getting condensation on my window. Hmm. So I turn on the defroster, and it doesnt work, I reach down and feel and the inside of the window is dry. The condensation is on the outside. So I use my wipers (which suck and need to be replaced, I've learned) to smear it away. it builds back up relatively quickly, not creeping all the way up the windshield, but consistently in a relatively small area near the center bottom of the glass.

What's the likely story here? It does not do it at lunch time, or at 5:00 - only in the AM.

[WolfeMan]

My guess/thought.

It's like fogging up your glasses by breathing on them - so I'm thinking some warm moist air is coming out from under my hood and fogging up the window. Some kind of air leak?

[One Keeper]

Heater Core. Do you smell anti-freeze?

[charlie tuna]

Too cold in your garage , as the windshield warms up the formulation of condensate disappears. The recent rains has our humidity up near 100 percent.

[WolfeMan]

Heater Core. Do you smell anti-freeze?

I do not smell antifreeze - but this seems logical. Would this mean that there is coolant leaking, and eventually the engine will overheat if I dont address it?

[reelhandy]

I don't think there is anything wrong. I get the same thing some mornings when it's humid. The air in the cab is cooler and dryer then the humid air outside, and it cools the windshield which is then cooler than the dew point. The more humid the air the higher the temp that dew (condensation) forms. That little temperature difference is enough to get the condensation to form on the outside of the windshield. If you turn on the defrost and set the air temp to warm it will clear it up eventually. It's easier to just use the wipers though. Running a cold defrost will only make it worse since it's just cooling the windshield even more.

[Juan]

There could be several reasons for the moisture on the windshield:

1. It's sucking moisture from the gulf and will eventually cause the ocean to dry up
2. You're driving through your neighbor's yard while his sprinkler system is running
3. You forgot to bathe and your windshield's eye's are watering
4. Your air conditioning is low on Freon which causes moisture and also attracts asteroids
5. Gremlins
6. Then it could always be a temperature change

[Ifishtoo]

There could be several reasons for the moisture on the windshield:

1. It's sucking moisture from the gulf and will eventually cause the ocean to dry up
2. You're driving through your neighbor's yard while his sprinkler system is running
3. You forgot to bathe and your windshield's eye's are watering
4. Your air conditioning is low on Freon which causes moisture and also attracts asteroids
5. Gremlins
6. Then it could always be a temperature change

Oh my, I'll go with 5. Wife claims they're always around! unlike asteroids!

[WolfeMan]

Hey, I'll take some ribbing if the outcome is that there is nothing wrong with my car.

[Harmsway]

Do you air condition your garage?

Fishin' is the mission.

[WolfeMan]

Do you air condition your garage?

Fishin' is the mission.

Nope, It's usually fairly warm in there. Especially if we park a hot car at night and then close the garage doors.

[charlie tuna]

I have the same problem with my truck anytime the "dew point" is low and high humidity exists. At first the entire windshield will fog over, then 3/4, then 1/2 , etc. until it disappears. And it disappears as the temperature of the glass warms up. If it was caused by a leak in any system, it wouldn't go away -- it would get worse..