Rear Aircon System and Heating

[brianh]

Thereââ,¬â,,¢s some vents behind rear bumper if I remember correctly.

Have you checked condition of your pollen filter and also does the recirc flap work correctly on front heater box?

Your memory is correct - if you remove the two rear flaps to access the bulbs from inside the boot, the flap is just visible inside the lower section (you might need to remove the jack from its stowage position). They sit around the side of the bumper, not really much to go wrong with them unless the space has been filled up with something stuffed in there?

Couple of things worth considering though as well as the pollen filter (and related scuttle drains or mobile swimming pool that can build up there if they are blocked)

1) air con might get cold, but does the condensate drain appear to be clear (should see dripping under car after its been switched on, somewhere near the gear stick around the front, don't know where the rear might end up if its a separate evaporator)

2) leaking heater matrix, or leaking rear screen washer (common issue being it comes apart in the passenger footwell) causing excess moisture be present. Does the rear screen washer work, do you have to keep topping coolant up? Is the front carpet wet? (possbile the pipe has started to leak if its not fully apart but not pushed together fully, poor design makes it prone to coming apart)

[yeshu26]

Thereââ,¬â,,¢s some vents behind rear bumper if I remember correctly.

Have you checked condition of your pollen filter and also does the recirc flap work correctly on front heater box?

Hi


* brand new pollen filter.

* No water in the any of the footwell.

*  I saw some vents inside the carboot (see attached link)/ I have cleared any stuff which was blocking them in anyway.
VCD showed nothing wrong with any flaps. As mentioned before I get normal air wrt appropriate settings from all vents.
The only exception is the glove box, where the air is always icecold. I just close it.




https://www.google.co.uk/search?q=vw+sharan+car+boot+inside&rlz=1C1CHBF_en-GBGB808GB808&tbm=isch&source=iu&ictx=1&fir=3HfKjTArmXe-pM%253A%252CHtgZjzbT7m3e6M%252C_&usg=AI4_-kQj8sFR_kpaWWu3MLKTGQ5oe5nVNg&sa=X&ved=2ahUKEwiyxK7djqreAhWFF8AKHfpfDSEQ9QEwBHoECAUQBg#imgdii=lKE96ch2irzqgM:&imgrc=HM44fPecxJcWuM:

[Chrispb]

Are you running with recirculated air? this will mist the windows as will not having the A/C in AUTO mode.

[johnnyroper]

Hi


* brand new pollen filter.

* No water in the any of the footwell.

*  I saw some vents inside the carboot (see attached link)/ I have cleared any stuff which was blocking them in anyway.
VCD showed nothing wrong with any flaps. As mentioned before I get normal air wrt appropriate settings from all vents.
The only exception is the glove box, where the air is always icecold. I just close it.




https://www.google.co.uk/search?q=vw+sharan+car+boot+inside&rlz=1C1CHBF_en-GBGB808GB808&tbm=isch&source=iu&ictx=1&fir=3HfKjTArmXe-pM%253A%252CHtgZjzbT7m3e6M%252C_&usg=AI4_-kQj8sFR_kpaWWu3MLKTGQ5oe5nVNg&sa=X&ved=2ahUKEwiyxK7djqreAhWFF8AKHfpfDSEQ9QEwBHoECAUQBg#imgdii=lKE96ch2irzqgM:&imgrc=HM44fPecxJcWuM:

Vcds might not show any faults but that does not prove the recirc flap is actually operating when commanded to by the motor.

[yeshu26]

Are you running with recirculated air? this will mist the windows as will not having the A/C in AUTO mode.

Always auto mode or the demisting mode for the window.

[yeshu26]

Vcds might not show any faults but that does not prove the recirc flap is actually operating when commanded to by the motor.

Where is it located? the recirc flap?

I can feel the change in car internal air pressure when I press/unpress it.

ta

[yeshu26]

ffs nightmare starts again lads.

[brianh]

Did you ever check the scuttle area up the front? (area near pollen filter, under the wipers) They are known to fill up with leaves and then water when it can't escape from the drain holes, if you have excessive water there (i've seen it manage to get a lot gathering there) that could introduce excessive water into the air taken into the vehicle as it is right under the pollen filter (or on the pollen filter in the worst cases).

Fix is to remove the plastic bit that sits in the drain hole and leave it out, this should allow most of the debris to fall through and out of the car then.

[yeshu26]

Yes cleared it.

The problem is the mixture of cold and hot air in the car.

Rear floor vent is blowing ice cold air (again).

Did you ever check the scuttle area up the front? (area near pollen filter, under the wipers) They are known to fill up with leaves and then water when it can't escape from the drain holes, if you have excessive water there (i've seen it manage to get a lot gathering there) that could introduce excessive water into the air taken into the vehicle as it is right under the pollen filter (or on the pollen filter in the worst cases).

Fix is to remove the plastic bit that sits in the drain hole and leave it out, this should allow most of the debris to fall through and out of the car then.

[brianh]

I'd suspect you have some sort of issue with a sticking distribution flap. Though no idea where to suggest on that one, as I don't have one with the rear A/C fitted. Its not too major to remove the rear inner lining in the boot and have a look whats going on though, I suspect thats where you'd need to start with.
Might be sorted with a few tactical applications of lubricant in the right places if your lucky.

[yeshu26]

Rear screen washer pipe gets dislodged from time to time in the "carboot", but never in the front area.

Your memory is correct - if you remove the two rear flaps to access the bulbs from inside the boot, the flap is just visible inside the lower section (you might need to remove the jack from its stowage position). They sit around the side of the bumper, not really much to go wrong with them unless the space has been filled up with something stuffed in there?

Couple of things worth considering though as well as the pollen filter (and related scuttle drains or mobile swimming pool that can build up there if they are blocked)

1) air con might get cold, but does the condensate drain appear to be clear (should see dripping under car after its been switched on, somewhere near the gear stick around the front, don't know where the rear might end up if its a separate evaporator)

2) leaking heater matrix, or leaking rear screen washer (common issue being it comes apart in the passenger footwell) causing excess moisture be present. Does the rear screen washer work, do you have to keep topping coolant up? Is the front carpet wet? (possbile the pipe has started to leak if its not fully apart but not pushed together fully, poor design makes it prone to coming apart)

[brianh]

That would be unusual, they normally come off at the front joint near the footwell.

[johnnyroper]

My washer pipe popped apart behind trim above the nearside rear light filling the storage area in quarter trim with water. Same
Naff fitting as the one that pops in front. Mine wasnââ,¬â,,¢t fully apart so rear washer still worked which meant issue was in noticed for a while.

[brianh]

If it is a problem like the front one is, I found 2 fuel hose clips one either end was enough to stop it coming apart again.

[johnnyroper]

Yeah same as the front not too bad to get to on standard models I added 2 cable ties to mine. On rear air con equipped cars itââ,¬â,,¢s a pain as ducting runs against it.

[yeshu26]

Thank you for the comments. Thermostat ordered.

Regarding the misting on the windscreen, it is worse in the rainy weather. I was suspecting leaky matrix, but I have not found anything nasty smelling or sticky on the windscreen yet.
It's a thin film of steam, which cleans off easily with fingers or hands.

[yeshu26]

Wait.... windscreen does get dirty from time to time with thin film which is like  stubborn water-vapour if that makes sense lads?

I will try to take a picture with a good camera if I can.

[johnnyroper]

How bad is the misting as in this weather is quite normal to get some as the air con will not be working due to low ambient temps?

[yeshu26]

How bad is the misting as in this weather is quite normal to get some as the air con will not be working due to low ambient temps?

In bad rains can compromise the vision or enough to annoy the driver. Aircon clears just a bit.

[brianh]

Wait.... windscreen does get dirty from time to time with thin film which is like  stubborn water-vapour if that makes sense lads?

I will try to take a picture with a good camera if I can.

It usually smears if its coolant and doesn't clean easily - the screen can still look dirty after cleaning. Depending how diluted your coolant/antifreeze is will effect how long it takes

But if your matrix is leaking, then you should be losing coolant out of the expansion bottle.

If it is leaking, then when i replaced the matrix on the mk1 I had to clean a load of gungy coolant (consistancy not far off golden syrup) out of the heater box to stop the flaps sticking, if you have got that leaking that might explain the problem. Theres no reason the back matrix couldn't be the one leaking though (and that one is a lot easier to access and work on, so I'd rule that out first!). Again if thats leaking you might find its causing flaps to stick, I'd also suspect that the back one leaking might not make a visible mark in the same way, as the antifreeze would have to travel a lot further before it got deposited on the glass, which given its not directly pointed to the glass probably wouldn't happen anyway.

[yeshu26]

Ok. So thermostat changed today. Tested with water and all was well. Since its freezing in Aberdeen, I asked the mechanic to siphon out good two litres of water. I had 2 litres of G13 at home, and drove couple of miles home at low revs to top it up. Low coolant warning came as expected, and engine temp went around 95-100. Reached home, topped up with G 13 concentrate, and now the bloody thing wont start. Ran VCDs with no fault code. After engine cooled down, it started no bother.

Now the grand finale, even though engine temp is around 90, the heater blower is blowing our absolutely freezing air.

I am banging my head thinking, now what the F!!!

[johnnyroper]

Mine tested in water fine when it was knackered,but they go weak so the pressure of water behind it pushes open slightly.

You have an air lock in the system by sound of it

[yeshu26]

Mine tested in water fine when it was knackered,but they go weak so the pressure of water behind it pushes open slightly.

You have an air lock in the system by sound of it

Ta mate.

What shall I do?

[johnnyroper]

Make sure return to expansion bottle is clear,top level and run up with cap off until warm. Top fluid replace cap and drive the car around for a while. Then slowly remove cap and leave to cool with cap off and re top level. Might take a day or so to clear all air locks,mine certainly did

[yeshu26]

Some coolant disappeared. Looks good. That is OEM g 13 one bottle. And one 2 bottles of prestone from ASDA so far. Hope prestone is same enough for my oldie.

[yeshu26]

Some coolant disappeared. Looks good. That is OEM g 13 one bottle. And one 2 bottles of prestone from ASDA so far. Hope prestone is same enough for my oldie.

NB# Looks wrt coolant seeping off slowly. The bl00dy thing still does not heat the cabin.

[yeshu26]

Finally! Drove 4 miles, till it gulped the expansion bottle dry. In total topped up 2+3+2 litres of coolant.

Nice and hot now. Engine temp up to 90.

ta lads.