Dirty Windscreen

[MisterTee]

I'm not sure whether this is unique to my car or whether anyone else has experienced this?

My car has developed a strange 'characteristic' lately that involves a very light greyish/bluefish film of dirt developing on the inside of the windscreen.

I'm having to use my car as my daily driver at the moment, so I have been using it more regularly than I usually would. I've also had to keep the roof on - partly because of our lovely summer weather, but more importantly, to keep the car secure whilst I'm at work.

I can clean the windscreen, drive to work (no more than 10 miles) and by the time I get to work it is noticeable, especially in line with the vents on the top of the dash.

I've tried turning the blower on, off, set the heater controls to hot, cold, cabin and demist and it doesn't make any difference.

Anyone else experienced this or any ideas what could be causing it?

Thanks in advance.

Andy

[GreenV8S]

Check the integrity of the ducts feeding outside air to the air vents. If you've got a leak in the engine bay combined with low pressure in the cabin (which you will have if the top of the windows don't seal) you could be pulling in dirty air from the engine bay. If so, I'd also wonder what nasty gasses it might be bringing in with it.

[phillpot]

GreenV8S said:

Check the integrity of the ducts feeding outside air to the air vents. .

I think the screen vents are fed via the heater which only draws air from within the cabin? Only vents that get fresh air are the eyeballs on the centre console. If the ducts to those are split as they run through the engine bay you may well get engine fumes, leaves, dead bugs and allsorts coming in.


Long shot but............. could there be a minute leak in the heater matrix and the "muck" is some kind of residue from vapourised/atomised anti-freeze?

MisterTee said:

I've set the heater controls to hot, cold, cabin and demist and it doesn't make any difference.

No, they don't do a lot on any of the cars

Edited by phillpot on Friday 21st July 07:13

[magpies]

phillpot said:

GreenV8S said:

MisterTee said:

I've set the heater controls to hot, cold, cabin and demist and it doesn't make any difference.

No, they don't do a lot on any of the cars

Edited by phillpot on Friday 21st July 07:13

I believe the controls do work once the dash has been removed and TVRs workmanship! has been corrected

[MisterTee]

Thanks folks.

I too thought that the only 'fresh air' vents are the ones in the centre consul. The ducting to those vents looks pretty sound. I must admit, I've not noticed any particular issue with fumes in the cabin, even when I've had the windows fully closed in the rain and the car doesn't lose any water, but .....

You did get me thinking about the vaporisation thing.

The car has a very slight oil leak from the distributor (I think) and oil does make its way onto the exhaust directly beneath the cabin. I have noticed the smell of burning oil the odd time when I've put the car away in the garage, especially if the car has been stood idling.

The search continues, but I bet the two are linked.

Looks like it's another job on the 'to do' list.

Andy

[phillpot]

MisterTee said:

The car has a very slight oil leak from the distributor

There is an O ring on the distributor (as you way well already know), not unknown for it to perish and leak.


It is also not uncommon for the rubber gaiter under the leather/vinyl gear stick gaiter to split or be poorly attached which would allow fume ingress.

[GreenV8S]

phillpot said:

I think the screen vents are fed via the heater which only draws air from within the cabin?

I think so too, but once you have got muck circulating within the cabin, it's eventually going to be blown up against the windscreen where it's likely to stick.

[Speed 3]

Funnily enough I've started getting this on my Tuscan, drives me made to the point of having a small bottle of glass cleaner in the car all the time. I did pop into my regular specialist to confirm there was no kind of filter to the intake. They didn't have any immediate diagnosis but we didn't have the bonnet off at that visit, will have to wait till clutch change. I too don't get any noxious fumes but suspect it must be some kind of engine gunk migrating into the system.

I will be interested to know what yours is if you cure it before mine goes in.