Coating on the windshield

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Henrik

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Hi!
Autumn has arrived in Norway and the heater and defroster system must be used in the morning. One problem I do not see any solution to have occurred. After a period of use of the fan I get a gray coating on the inside of the windshield. There is no humidity and it does not disappear before I wash it off. I've checked under the hood and there is no smell or oil vapors or other things that seem to be drawn into the heating duct. Anyone else experiencing the same problem?
 
Never been to Norway to sample the humidity but once in a while, one or another of us has a problem with the heater core leaking coolant. It may start as a very small leak, which might not be visible on the tunnel or in the carpet, just enough that the heater fan blows it onto the windshield where it condenses and stays.

I would wipe it up with a clean white tissue and compare any visible color to the color of your coolant. If there is not a color match, it likely isn't coolant and you likely don't have a heater core issue. Thank your gods.

Another possibility is that you have recently treated your dashboard with a protectant which evaporates and condenses on the inside of the windshield. These can be difficult to wipe off the windshield because they are "oily" and some sort of cleaner may be needed to remove them from the glass. This condition will re-occur as long as there is protectant evaporating from the dash. Wipe the dash thoroughly to remove excess protectant, and the condensation may go away in time.
 
The first thing I did was to investigate around the heather core to see if there was a leak, but luckily there was none. The "smoke screen" on the windshield continues to be there even after the sun has heated the windshield, so it can not be condense. The only medicine is to clean it with soap and water.
A friend of mine has exactly the same problem with his E9.
Pollution along Norwegian roads have not reached the same level as in Mexico City yet. So it can not be the reason!
 
Not exactly sure how the coating ultimately made it onto the windshield, but I was getting a grayish film. It disappeared after another problem was addressed.

I had a leaky brake master cylinder. Leaked into the booster and with its vacuum connection to the intake was actually burning he fluid under high load.

Also leaked into the cabin on the inside of the fire wall. Assume burning material was sucked into the air intake for the heater / fan or maybe just circulated inside the cabin can't say.

However...after replacing the master problem was gone.
 
How about exhaust? Do you smell any exhaust in the cabin? I did and replaced the firewall plenum rubber seal and also had the exhaust manifold "polished" to minimize leaks there.

If you are brave put some of the residue in your tongue and report the taste.
 
I can´t smell anything suspicious. There are no leaks of any kind. The only thing I can think of if there is any oil vapor coming from the engine. Venting from the top cylinder cover enters the throttle housing, the hose may be leaking? Anyway, there is a seal between the hood/engine compartment and the air intake so I find it odd if something comes from the engine. I will do some testing during the weekend to se if there is any difference with heat on and off while the fan is on.
 
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