I started to experience this just this spring/summer after having my xfire since last October. The windshield will completely fog-up with zero visibility within about 10 seconds...defroster does nothing for at least 2 minutes. I've almost wrecked twice because of it...last time I was 'merging' at 85 on M-59 ;-)

Usually happens during big temperature changes or a drop in the barometric pressure outside. There are no visible chips or cracks in the windshield. OEM windshield, not replacement.

Could this be a problem with the windshield housing? Should I take it to the dealer? Any help would be appreciated.

 

I have never had the entire windshield entirely fog up, though my car stays in a garage most of the time.

Usually the fog is from difference in temp from the outside to the inside. Now being so hot on the outside, if you keep the ac kicking on the front defroster it may cause that issues.

Though, in your case something different may be happening.

p.s. i assume this is happening while you are driving, if not maybe let the windshield thaw out before driving!

 

When you put the defroster on, bite the bullet and crank it up to 5 WITH the A/C button pushed. It usually only works, or works best (and fastest) when the a/c is on...

...well I just re-read your post that it happens during spring/summer, so maybe the A/C won't help you. As stated above you need to try to match the inside temp with the out...I haven't had it happen during the day when it's warm, only at night when the temp drops after a warm day, I can never get it to unfog without using the A/C...

 

Its not the car its the difference in temp. It will happen in any car. Happens in my Porsche as well as my Sterling. You need to equal out the outside to inside temp.

 

Check that the air conditioning water drains are not blocked. If they are it will cause moisture to form on the windshield.

 

My initial attempts to fix this was to equalize the temperate in/out (if its cold out A/C and if its hot out heater) - no go. I even tried the polar opposite out of desperation. The only solution is to pull over roll down the windows and wait 3-5 minutes.

Could it be the windshield seal?

 

Check the recirculation switch. If you have it on recirculation it will fog the windows.

 

I hope I understood the problem right... otherwise excuse my indoctrination ;-)
Does it happen when you used A/C and switch it off? If so, it's normal. While cooling, the air reaches 100% relative humidity (condensated water drains). When you turn off A/C, the warmer air with more humidity hits the cooler windshield and condensates.

 

I have the same problem when it rains and I have the A/C & Defroster on. The lower part of the windshield will fog on the outside of the windshield. If i turn off the defogger or A/C the fogging will stop and dissipate. The average temp here in Varina, Va during the summer is 86-95 degrees with 100% humidity. I would assume that the temp drop and the rain cooling off the windshield and the heat generated from the engine while the A/C or defogger are in use causes the fogging.

 

It may be the recirculation switch. We've had a very hot month or so here and in the manual it suggested hitting the recirc switch on hot days to cool more efficiently. I'll keep it off and see if that stops the fogging.

 

Happened to us too, but usually in the winter the fogging would actually freeze on the windows... made for interesting driving! The fix is a new A/C compressor, go to the dealer its well documented...the A/C is meant to come on as soon as you try and demist.

 

K and K,
Excuse my ignorance, but I have the same sort of issue... freezing outside windshield, and major fog issues really fast if a rain drop falls on a summer day... Almost got 18 wheeler road rash!!!
Anyway, this is a compressor problem???

 

I have had this too... hot day high humidity (95+) then late in the evening when the temp drops down to 70's window completely fogs over. Luckily I was in a subdivision so I stopped in the middle of the road and tried to figure it out. Had AC on entire time, tried the recirc but that seemed to make it worse, opened the windows to no avail, turned on the heat but that didn't seem to do much, at least not very after 30 seconds, so I went back to AC and it slowly cleared it up. But as I drove home, through certain areas the window would suddenly fog up and just as face clear up a big down the road. Its all from the temp/humidity combination/difference and I don't think there is any instant fix or cure-all. I have had it happen with ever car I have had in this area.

 

I'm having this same problem. I know when I was in Germany we had a MB van and it did the same thing, I'm thinking this is normal for them. Tonight I was driving down the highway and after driving about 45 mins the windshield started to fog up so I hit the defrost and boom, I couldn't see. I mean boom too, it took less than 2 sec. to get to the point I couldn't see. It took almost five mins for it clear up. It just got so humid in the car my glasses fogged up to. It felt like the A/C was pumping humidity into the car. I think I'm going to call the dealer up, because if this happened in traffic, I know I would have hit someone.

 

It has been my experience that the defroster (front) efficiency is greatly increased, if you manually close the three dashboard mid level vents. Give it a try... this may solve your problem.

 

As stated above, close the dash vents, The owners manual covers the subject and advises you to close the center vent when using defrost. It's a MB thing, German technology. ;-)

 

My first Xfire (vin series 9xxx as I recall) had this problem. Two suggestions:

1) After running the a/c, park the vehicle and verify that you have water dripping from the condensate line on to your driveway. If not, the condensate line is blocked and that's your problem.

2) If #1 doesn't solve the issue, then your recirculation valve is stuck in the closed (recirculation) position. You can verify this by setting the fan on it's lowest setting with the engine off and hitting the recirculation switch. If you don't hear the sound of the valve (slight clicking noise) switching between the open and closed position, the valve is stuck or inoperative.

One of the above should solve your problem. (Good luck with the dealer!)

 

Has anyone tried just using that "anti-fog" spray stuff that is made for bathroom mirrors and such?

Might or might not work but would be worth a try...

 

I think Rain-X is supposed to help with that kind of thing too... if they still make that stuff.

 

1. I know about the dash switches.

2. Rain-X is not a solution it's a band-aid. I feel a $35,000 car should have this problem.