Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Workshop note: Misting gauges 2003-6 dashboard

So yesterday morning was cold, and therefore ideal for test run.

After 45 miles, three small instruments remained clear. The oil pressure gauge had very slight misting, but hardly anything.

The heater was on full, with occasional use of the fan.

More interesting is that my speedometer slightly misted over in the centre. So far I haven't drilled the two large gauges because they rarely mist up. When they have misted up, the four small gauges have been impossible to read. I therefore conclude that I have almost solved the misting.

Perhaps I may drill the large ones over winter. We'll see.

I have been reading this with interest, my gauges haven't misted up at all until maybe 2 weeks ago during night driving, they had been fine all evening, then suddenly misted up, only gauge that doesnt seem to suffer is the rev counter,

Mentioned this to BHM, a known issue and the only fix at the moment is to direct the heater output to the back of the dash, they have tried drilling holes but without success apparently, maybe it varies car to car? Disappointing though as none of my classics suffered with this issue.

I am not feeling brave enough though to start taking my dash apart so may just live with it.

Maybe not enough holes? I went the whole hog on holes, and the reflect-a-cool underneath. I need a frosty morning to double check.....................

Is there a reason the manufacturers don't put holes in the rear? My gauges always mist badly - I sort of ignore it. It's bad enough some days that I cannot read the speedometer at all.

Weird...we have virtually identical cars and none of the dials ever mist up.....
Is it because the garage, and thus the car, is part of the house and the temperature never falls below 10C?
I've no idea!

I do have a problem with the wing mirrors misting up... need electrically heated ones

Dave, on the way to the TV Mog meet at the Vyne my 4 small dials misted up.

The LED route seems not to work. I am thinking of making more holes or of taking a feed off the heater to all of the gauges. My only worry is that is I blow in air it needs to be flitered to prevent dirt in the units.

Just an off the wall thought but perhaps the reason why these cheap gauges are so prone to misting is because they have plastic bodies. I would guess that maybe they are manufactured from ABS or similar which is a hygroscopic resin. The hygroscopic nature of the plastic will attract and store water molecules so will generally be saturated. So maybe wiring the bulbs (not leds) to be permanently on all the time would offer a degree of heating and help keep the average moisture content down?

Or replace with water tight instruments

Water tight instruments might not help as the water molecules would probably migrate through the body from the outside inwards?

That is interesting as mine didn’t mist up for 1st 2 years of ownership. They now mist up on most cool days. Hadn’t thought of hygroscopic effect.