Fogging speedometer

[awolff280sl]

My speedometer glass fogs up somewhat while driving and clears up overnight.
The car has not been in the rain nor has any washing in the engine bay been done. The cable and dash gasket have been replaced recently. No other instruments are affected. I did put a bit of lithium grease down the cable before installing it, but did that for the tach as well. ?

[graphic66]

Mine always has also. I think it is normal for these cars. The gauges are not hermetically sealed at all. The fog goes away after the weather dries out. Maybe it is the Mercedes humidity gauge.

[awolff280sl]

Oh good, someone else has this. I thought the car was haunted.

[forrestjordan]

Had the same issue with my 69.  Seemed like never knew when it would happen.  My heater control knobs were broken off and after fooling around with the settings for them with a screwdriver, to adjust for cooler air, it never seemed to fog up again??  Don't have any idea why!  Next time it fogs up, try adjusting the air flow and heat etc. as see what happens.  I live in Sewalls Point, Fl so may it is a humidity gauge.  I will be working on the control knobs next Fall when the weather cools off.  Will you be at the Naples Show?

[benzportland]

My clock does this if I am driving with the top off.

[awolff280sl]

I haven't heard about the Naples show. I've never "shown" the car, not sure if it would show too well, but drives great. Where's Sewell's Pt?
I'll mess with the levers and see what happens. Thanks.

[psmith]

As discussed before, these cars are a "chick magnets" but what ARE you doing in your Pagoda that fogs up the instruments   :oops:

[thelews]

quote:Originally posted by psmith

As discussed before, these cars are a "chick magnets" but what ARE you doing in your Pagoda that fogs up the instruments   :oops:

Enjoying himself.

[Cees Klumper]

Mine's never done this.

[awolff280sl]

Natuurlijk, uw dijken houven het droog.


Moderator: Andy, we need a translation else we'll think it's nasty and remove it.
Richard M

[awolff280sl]

Translation: "Naturally, your dikes keep the water out".

[forrestjordan]

My wife will agree with the "magnet" thought, but I totally lost the translation thing with the water, is that the same as fog, and what are the "dijken"?  Can someone explain?

Sewalls Point is just East of Stuart, on the Indian River.

[awolff280sl]

Lost in translation...(dijken are dikes, it's what keeps the sea from covering the Netherlands)

[Cees Klumper]

This is a strange thread ... gauge glasses fogging up while driving, top up or down? Never heard that before. And, yes, the dams do keep the water out (which is good considering I am typing this from my living room on the second floor of our house, which I believe is still below sea-level!), but we still have water coming from the sky, it can be quite humid at times, but still I have never had this issue. One not-so-good scenario would be that there is water under your carpet in the footwells that, when the car heats up in the engine compartment and passes through some of that heat, it affects your instrument dials. That does happen on my boat, but in that case there is always some water down below that is humidified by the engine heat and so then travels up to where the instruments are (Volvo Penta). Better check for water/high humidity behind or below the dash.

[awolff280sl]

In my case (and it seems like I'm not the only one), I have my soft top up. There is absolutely no water nor moisture in the cabin, that is for sure. What I DO have is heat that seeps thru my vents, if opened, when the heater valve closed. Whether this is a result of 1. a leaky heater valve (despite just being redone), 2. Heating of the rest of the core by hot coolant at the copper intake pipe up to the closed heater valve, 3. Some other internal flow mechanism in the core, I don't know. I plan to install a 3-way valve in front of the core intake pipe and be able to shut off flow to the core entirely, and bypass it past the core outflow.
Since the speedo is closer to the core than the tach, this may be related to why only the speedo fogs.

[awolff280sl]

Speedometer fogging problem has been solved. Turns out there was no rubber seal between the speedo cable and where it inserts into the hole in the back of the transmission. From what I can tell there are 2 different types of ends on these speedo cables, depending upon which one you get. The "original" style has a groove near the very end that holds the lip of the rubber seal. The other type has no groove and more of a blunted end and you cannot fit the seal over it. I have this second type of cable so first I decided to cut a short piece of 3/8" hose to use as a seal. While this does work, I did not like the rigidity of this hose. I did have an original seal lying around which is alot more pliable and likely to give a better seal, but it does not fit over the end of my cable and therefore relatively too long. However, I was able to use it by pushing the end of the cable up into its hole with enough force to be able to "condense" the seal and thus insert the locking bolt.  No more fogging.

[Xenograft]

I have been caught in a really heavy rain a few weeks ago. Since that time my tachometer developed fogging issue. Recently I also noticed some fog on the central gauges. How do I get rid of it? Any recommendations?