can't demist the windows, steam coming out & foul smell. Any ideas/help

[paulcalf]

Hi my poor old a3 8l is struggling to demist the windows.

Its standard heating / no air con.

At first i thought it was rain getting in the pollen filter as one of the plastic rain deflectors has broken off and I couldn't work out how to re fix it.

Now I'm not so sure.

When the engine is hot and i turn the heating on loads of 'steam' comes out of the vents.

After a while the 'steam' clears, but no matter how much hot air i blast on the screen it won't clear the 'mist' properly.

Any one good any ideas on how i can cure this please? or what the problem is.

Is it likely to be rain getting in the pollen filter or a problem with the heating system.

The passenger floor is dy.

I don't know how the heating system work.

I have done various searches on the forum, but can't find anything that is like my problem.

Please help

Thanks

Paul

 

[hendo#1]

Heater matrix.

The mist is antifreeze.

I had a Leon Cupra R do exactly the same years ago. Luckily the warranty covered it.

Its a dash out job to change I believe.

 

[paulcalf]

Heater matrix.

The mist is antifreeze.

I had a Leon Cupra R do exactly the same years ago. Luckily the warranty covered it.

Its a dash out job to change I believe.

Thanks so much for the reply.

Damn that sounds like a huge job, it may not be worth it.

Car still drives great, but a few issues need sorting now and it may signal the end of the road.

Is there any work around like some leak repair fluid, that would mean the dash doesn't have to come out.?

Car is a W reg with 170k, most of them done by my family.

 

[hendo#1]

Run your finger down the inside of your windscreen and taste it.

If its sweet tasting its antifreeze. Its poisonous so don’t be doing it a lot!

At 170K miles you have nothing to lose by putting in some radweld or similar, although I would never normally recommend using it.

You may get lucky with it.

 

[<tuffty/>]

Almost certainly the heater matrix and as already mentioned its a bit of a job to do... had to remove the whole Dash on my A4...

This should help give you an idea though...not immediately obvious whats going on but pretty sure you will need to remove the dash and you will need to degas the aircon too as the whole heater assembly needs to come out
https://workshop-manuals.com/audi/a...ioner/heating/removing_and_installing_heater/

<tuffty/>

 

[paulcalf]

Run your finger down the inside of your windscreen and taste it.

If its sweet tasting its antifreeze. Its poisonous so don’t be doing it a lot!

At 170K miles you have nothing to lose by putting in some radweld or similar, although I would never normally recommend using it.

You may get lucky with it.

I may well give that ago.

The car has been nearing the end for sometime, but I love it and it still drives well.

Equally I can't justify spending a fortune on it

 

[paulcalf]

Almost certainly the heater matrix and as already mentioned its a bit of a job to do... had to remove the whole Dash on my A4...

This should help give you an idea though...not immediately obvious whats going on but pretty sure you will need to remove the dash and you will need to degas the aircon too as the whole heater assembly needs to come out
https://workshop-manuals.com/audi/a...ioner/heating/removing_and_installing_heater/

<tuffty/>

Thanks for the link, I'll have a look.

No air conditioning on my A3

 

[AGB-S3]

Could be the bulkhead heater water feed-through's , mine had been cocked up with silicone ,
by one of the previous owners , or mech's ,
Causing water loss and mist , luckily , new seals + pressure test, all was ok ,

 

[paulcalf]

How would I check those?

I doubt it's that though as we have owned the car since nearly new, so know who has done what to it since 35k miles

 

[AGB-S3]

Have to follow the water feeds from the engine bay , through the bulkhead , must be tucked up behind the center console, mine where leaking coolant , causing the water low to show , guess it was the engine side , the initial thought it was the head , as the radiator etc where all ok, no obvious point of loss ,

But on the Ford , that went , first off started getting a sore throat , and light misting on the screen , had to run with the header tank cap loose , till got a new rad , but that was the v6 24v , big engine , so hardly stressed at low speeds , this may not be tolerant , probably boil over

 

[AGB-S3]

Just remembered , was found during a pressure test of the radiator and water system , after everything had been flushed out , 2 years on, end of last year, water pump was found to be leaking -

 

[paulcalf]

Just remembered , was found during a pressure test of the radiator and water system , after everything had been flushed out , 2 years on, end of last year, water pump was found to be leaking -

I've had a look as best I can. I can't see any obvious issues with those pipes. No wet carpet or damp around the centre console.

I'm pretty sure my issue is the heater matrix.

I spoke to my mechanic who said he reckoned he could do it in approx 4 hours, I mentioned trying rad weld first and he suggested trying Bar Leak which did a product that hopefully won't mess up my heater core.

https://www.ebay.co.uk/i/173550656872 is on order. Rislone is what Bar Leak is called over here it seems.

 

[AGB-S3]

Could be a one way trip if it clogs up the water ways in the head and the main rad ..
if the car is in good condx , 4 hours and the part ?

 

[paulcalf]

Could be a one way trip if it clogs up the water ways in the head and the main rad ..
if the car is in good condx , 4 hours and the part ?

Yes 4 hours plus the heater matrix

It drives well, but is a W 2000 car with 170k on the clock serviced every 10k/year, so engine is good,loads of history and work done, but car is old so various things need doing each year.

MOT due in March
Front discs probably need doing at MOT
Alloys are rusty/damaged so tyres go down - need new wheels
Think a front wheel bearing may be on its way out
Airbag warning light on (happened before and was an easy fix)
Service

I want to keep it going, but just not sure about spending so much? on such an old car.

Happy to hear peoples thoughts