Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing DaveW's Skunk Works - Misting Instruments

A long saga, of failure so far over 18 years.

On winter mornings, roof down, the four small gauges across my Roadster dash would become completely unreadable. The two big gauges, semi unreadable.

Step 1: Apply a clear plastic layer to the small gauges, for extra insulation. This provided a marginal improvement.

Step 2: Try with or without sidelamps on.Worse with 'on'.

Step 3: Drill a load of holes in each instrument, the theory being that if the air can convect easily, condensation will reduce. This was inconclusive.

Step 4: Added a leather apron from the top of the dash, over the instruments and gauges.This was really to protect the underdash from the ingress of water, from leaks around the wipers and washers, but also if the washer tubes fail. This is a worthwhile addition, even for the CX cars. This didn't affect misting up.

Step 5: This is more recent. I can't remember how this occurred to me, but I added a thin piece of acrylic sheet over the four small gauges. It secured under the top of the rail, using self adhesive sponge profile. In Scotland, although it wasn't cold enough for a winter test, I had no misting. But what was more interesting was that with the roof down, this thin piece of acrylic fluttered constantly as the airflow curved over the screen and buffeted it quite hard. So this is the cause of the misting. You don't feel this on the road, but the dashboard is getting a constant flow of fast moving air, and on a cold morning, this is cooling the outside of the gauges.

This was my test rig:


It was convincing enough for me to extend this trial into using rigid 3mm actylic, which I added this morning. I won't know how well this will work until some winter runs, but I'm hopeful.

Roadster:




GDI:




I use The Plastic Man, which is where my windbreak also came from.

FWIW only had this issue once with my 3.7 Roadster mainly on the tacho nearest to me being part of the Mustang instrument module used by MMC for this model.

I think I can explain the reason though. It was a cold but humid winters day albeit with dry roads. I had the heater full on with top down. This would have lead to big temperature difference between front and rear of instruments hence warmish humid air causing condensation on inside of cold glass.

How about some of that tracer cable heater wire that they use to stop pipes freezing, wrapped around the gauge casings wired to a little rocker switch under the dash