Why does only one gauge fog up?
 

Seems like I've read other posts indicating the propensity for only the oil/temp & oil pressure gauge to fog up. Why would this be?

We've had rain in ATL for 7 straight days so it extremely humid...past couple of days the oil pressure gauge has totally fogged up and nada on the others. What gives?

Same problem on mine. It tends to fog up early in the morning after a somewhat cool night.

Mark
Me too - though I haven't been driving in the floods like you.

WTF? Same here, started just last week in the cooler evenings. And ONLY the oil temp/pressure gauge.
Looks like only Carrera 3.2's on this thread so far....

Same with my 86 3.2. Was going to just swicth out the gauge but it seems there may be more too it if lots of people are having the same issue

At some point water found its way around the gauge.

When I first got my SC the same thing happened. Water was getting past my windshield seal and running under the dash. Two of my gauges were fogging.

I replaced the seal then pulled both gauges out and used a hair dryer to get rid of the moisture. In all likelihood you won't be able to "see" moisture in the guage ... but if it is fogging ... then the moister is there.

Same issue on my 75S and 73.5T. Without any real investigation, I'd guess it has to do with the location of the gauge--directly in line with open area to trunk--and the construction of the gauge itself--possibly more openings to outside atmosphere in the case or more "empty" space inside the case itself allowing for easier condensation. Just a wag, and something to live with during the cooler months.

Add my '75 S to the list. . . I wonder if replacing the gasket would help

Ditto on the windshield leak - had the same problem with foggy gauges which stopped once I fixed the leak.

In my 1973.5T, 1974 911 and 1979SC the guage has never failed to fog under certain conditions. I attribute the fogging to the location closest to the door and outside conditions. I have never had a failed or faulty guage as a result of the fogging in any of these cars over a span of 30 years.

If it did not "fog" it would not be a 911!! :D


Bob
73.5T

normal. smoke at start up, normal, g50s rattle, normal, heater could work better, normal, etc. they have quirks.

Here's a curve ball for you!
My SC did it last week while out on a short hop.
And the car lives indoors, it wasn't raining. I suspected that the cool temps of the basement combined with the rather hot and humid ambient temperature caused it, much like when my camera lenses fog when going outside from inside the house.
I will check for water leaks, though!

Mark,
Mine was doing the same thing. I did a search here and there was a very good thread on how to "carefully" take the glass off, clean the glass, let sit a few days to get humidity out, then carefully put glass back on.

I did it and mine no longer fogs up....

As I remember, you have to use a tiny screw driver to carefully pry open the lip of metal that holds the glass on. I used one of those eye glass screw drivers.

Do a search, I'm sure you'll find it.

I think 3 or 4 (left to right) of mine will do this on cool mornings, if I have the top down

happens in the PNW all the time so I looked into the cause, plenty of moisture outside but none behind the dash. after pulling the gage, I noticed a whole in the firewall leading to the trunk. I left the Gage out and drove around a bit an sure enough, you an feel quite a bit of air coming from the trunk area. So, I figure that moist air, from the trunk, is being blown in/around that gage combining with increased OAT and elevated moisture and most of the time the Gages are cooler than the outside=fog/condensation. I'm working on a deflector for the back of the gage (just some cardboard or plastic) that should help.

So yours is fogging on the outside of the glass (meaning that you can wipe it with your finder) and not the inside?

The gauges don't have the best seal but they still shouldn't fog on the inside. I suppose it is possible but in 2 1/2 years since I replaced my windshield seal, I haven't had any issues. My car is also stored inside and it is hot and humid down here in Charleston.

Add my 75 to the list. Its stored in the garage and hasnt been in the rain. Took it out last night and the oil/temp gauge fogged right up. Its been doing it for years.

Sorry, I am with John on this one.........."normal". Some quirky things about the 911 must remain!

If I had to advertise my 911, it would have as part of the description, "fogged left instrument" as factory specified..............

:D

No... When I first saw it I did the finger wipe and was quite dismayed to see it was inside. :eek:
But, I did have the fleeting thought that this was a "normal" 911 quirk and wasn't too concerned with it.

I know Charleston's humidity well. Birmingham has the same humidity with none of the Charleston charm!
We're there a couple times a year. Absolutely love it. I'm trying to get the finace' to apply for admittance to the SC bar so we can move there! Sullivan Island is my favorite place. Folly Beach, too. But if I had that mythical boat load of money I'd buy a house on Sullivan in a heart beat.

I guess that I would be concerned that water was entering the dash area. Or that rust might form around the windshield if the seal is leaking. This is what I saw when the shop had my glass out.

"normal" no ... "tolerable" probably

OK, normal it is. I do know for a fact that my windshield seal leaks.....In heary rainstorms I do get some ocassional drips on my left ankle....maybe not normal but I'm living with it.

Thanks guys!SmileWavy

LOL, same on my 930, I only have to drive out of the garage into a foggy day, that's it:D

I have a 86 3.2 also and ive been getting fog also in the oil pressure, oil temp, and tachometer........I live in atlanta also ............hmmmm

Can anyone say foggy gauge government conspiracy? hahah

anyone had any luck by sending the gauges out to Palo Alto or Hollywood to be resealed?
I bought a few replacement gauges and was going to send my oem's out for rehab.

not a problem on my 73 (115,000 miles), but pops up on my 77 all the time (102,000)

Bill K

Just to add another twist to the saga,

I have a 914 resto that I put a full 911 dash into and the the car has not seen the "outdoor light of day" yet and little lone even been wet.

911 Dash

The gas/oil gauge fogs up after starting the engine and running a while. None of the other gauges do this.

Is it possible that the gauge movement coils have some moisture in them and when running they slightly warm up and release the moisture?

:confused:

My car does this as well.

Here's my guess. The air inside the gauge is roughly the same humidity as the ambient air. As the engine warms up, the air pasing through the heating ducts behind the left side of the dash heats up, which starts to heat up the left side gauge. When this happens, the glass face is the coolest part of the gauge and the moisture from the air inside the gauge condenses there. The left side is more prone to this because the left side of the dash is closest to the heat ducts. The guage is nearly (but not quite) air-tight and the air is stagnant inside so it take a long time to equilibrate with the outside air.

Just a thought....

My 964T does this as well. Its my fuel gauge. I took it all apart, as it was on the inside. After carefully prying the ring apart and removing it, I discovered that it is actually the glass de-laminating in between.

My SC is kept inside an air conditioned garage and its heated in the winter. The car does not get driven in the rain and I ca not remember the car getting wet in the last five years. I have never taken it to a high pressure wash. I took it out last week and one of my gauges fogged. I figured it was becasue it was nice an cool inside then I took it out in the heat.

Nice theory, but I do not have heat exchangers and no heating at all, so it seems not to be the reason for our foggy gauges. Further, because my car is without any carpet, bitumen and other dampening and sealing, but full of holes like a swiss cheese (I know what I'm talking about as Swiss), there is probably the same humidity in the trunk area like outside...

Aw, just fog it and live with it! Happy autumn everyone! SmileWavySmileWavy

proffighter-

Yeah, I agree. I just pulled the gauge and looked behind it and there isn't a heating duct anywhere near it, so I am officially stupid. I knew I should have looked before I posted.

It is funny that my car has been on stands in the garage for a year and the gauge is STILL fogged up!

Hey there,

I have the same issue on my '81 SC. How did you remove the gauges? Do you think it's worth it?

Thanks!
James

I put a small desiccant pack (the kind that comes in a pill bottle) inside my gauges and it fixed the problem.

Add mine to the list. 89 3.2 is never driven in the rain but sits in a garage that is cooler or warmer depending on the weather. I believe it is the humidity causing the condensation. Only the far left gauge fogs and that is one of the three that was sent out and rebuilt by one of the speedo rebuild companies. My guess is that the seal is leaking and moisture (humidity)is getting in. I can live with it, at least it is not the tach or speedo. Steve

My oil pressure gauge has done the same thing I discovered that when it occurred that it was the only gauge in the dash that was warm probably the defrost duct heating it cold dense air plus warm air equals condensation if we all have the same gauge doing it and it hasn't been raining that's my guess

Add my 79sc to the list... Along with smoke on startup, moderate heat in winter etc...

Fellas, foggy gauges is not normal.

The culprits:

Loose Wiper Nozzles
Loose Wipers
Clogged or dislodged fresh air intake scoop or drain
Windshield Seal

I had issues with a drip on my passenger side, drove me crazy. I was detailing my car and noticed my nozzles and wipers were loose. sealed nozzles and tighened the wipers. Tested no more leaks. The one night I decided to work on my AC. I went in for dinner and turned my garage light off and left the hand light on. To my amazement I saw pin hole lights coming from my trunk into the cab area under the dash. Sealed all pin holes. No more leaks

j

Don't any of you have the anti-fog pump? Mine, I thought they all were, is mounted just behind the brake fluid reservoir on my 74. Tiny rubber lines are routed to each gauge. If these rot, or are carelessly knocked off, or even eaten by rodents you will have no end of trouble. Lose one line and get one foggy gauge. McMaster in LA sells the rubber tubing, N.H. Speedometer and others can rebuild the very tiny pumps.

Mine did this as well.

I got some 'rockwool' house insulation and packed it behind the instruments.

Doesn't do it anymore.