The heat I miss inside

Dawheeler

Dawheeler

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Hello all,

so my problem just started after I bought my 2013 A3 2 months ago and changed the timing belt and everything that should be changed after 200k if you bought a used car.

The heating just went dead. Even after 20 mins of driving i had to run it 3000+ if i wanted some heat and that is absolutely wrong, so i went back to the service.

they changed both thermostat, water pump, cleaned the heater matrix with some special cleaner and they said it should be fine now. It is definitely better but even after the water reached 90 the air on the left side is warm but not hot even on Hi, and the right side is much cooler than the left. And if i just stop driving but let the engine run, the air is getting cooler and cooler. In addition to this, start-stop isnt working while heating is on. If i turn it off it works.

outside temp is around 0 celsius.

there is no faulty code from vcds.

any idea?
 
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The start stop won't operate if the heating is set to high but as your climate is messed up it probably is affecting the start stop. I suspect a sensor but surprised there are no fault codes...
 
It doesnt really matter if my heating is set to 20 or high, start-stop wont start until i switch the whole thing off.
 
audi upgrades
1st thing I'd ask is, are all coolant pipes in the bay getting hot, if not then this is the issue, air pockets.
 
I had the same issue. It was the coolant valve that had stopped working. It was corroded inside and wasn’t fully opening to allow flow to the electric coolant pump and then onto the matrix. It didn’t show a fault code. It’s now proper hot.
 
I had the exact same issue, warm air on just one vent. You have to change your heater matrix as it is clogged. I installed a Nissens made one, and the heater blows really hot now.

The OE heater has really thin water passages and they get clogged by deposits. My OE one was so clogged that even air barely passed through it. After I got it off the car I tested it by letting hot water pass through it and only 1/4th of the heater's surface got warm. I think is the same in your case and that's why you get some warm air only on one vent.
 
Good shout, but do a HVAC calibration 1st to see if a motors faulting.

Not sure how easy or not on the 8V is for the matrix, but some are a pain.
 
NHN said:
Good shout, but do a HVAC calibration 1st to see if a motors faulting.

Not sure how easy or not on the 8V is for the matrix, but some are a pain.
Click to expand...

never seen a car that wasnt a pain to change :confusion:.
 
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We know that hey bud lol
 
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A side effect of the clogged heater matrix, besides the heat loss in the cabin, was that the coolant was being spilled out of the expansion tank on longer journeys.

Not the hardest to replace. To get access to the heater you need to remove the center console and:
-on LHD models you need to remove the knee airbag
-on RHD models you need to remove the glovebox and the fresh air blower
It's also recommended to disconnect(and clamp) the hoses going to the heater matrix from the engine bay and blow some compressed air through one of the exposed connectors to get most of the coolant out of the heater so you won't make a mess inside the car. Getting the air out of the system afterwards can be an issue. ODIS has a guided function for this that takes around 40-50minutes.
 
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tquattro said:
A side effect of the clogged heater matrix, besides the heat loss in the cabin, was that the coolant was being spilled out of the expansion tank on longer journeys.
Click to expand...

Actually, I just remembered, the coolant loss was happening during a DPF regen. So if yours is not a diesel(or equipped with a GPF), that might not happen.
 
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I generally left the cap of overnight, also refilled very slowly when doing coolant related work, clamps are elsawin route, but I couldn't be bothered tbh lol.
 
I’ve got the same problems and symptoms on A3 8v that I bought 2 month ago
Tried unblocking the heater matrix but the result wasn’t that good. Ordered new one from Germany
The car is going in a garage for new belt and water pump. Hopefully the matrix will be here on Monday and I can finally drive without gloves
 
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