Coolant Level Warning & Heater Issues...

Newbie Joined: Oct 15, 2014 Posts: 2

I've looked across the forum here and the internet generally but at a bit of a loss.

I've got a 2008 A6 2.0tdi auto estate. 92k miles. Its overdue a service but has had Audi Main Dealer its whole life.

I used to do a lot of miles on motorways but since losing my job its hardly done any (maybe 4000 this calendar year). A while back it threw a coolant level warning, so I looked at the awful shaped / designed header tank and waited till I was at home then topped it up. Little while later did same, thought it was odd. Topped it up.

About a month agao, I sucked up the expense and sent it into Audi. They had it 3 days, ran two pressure tests on it - the second one with dye in it to perform a UV check. They confirmed to me its not coming out the exhaust, there is no visible water leak or aerosol leak either. It got to the point where they told me that they didn't doubt the light was coming on but they couldn't find a reason for it. Fuel economy is about where it should be - so didn't think it was an EGR leak either.

Now, every time I drive it - light came on. Now every time I start it / drive it the warning comes on. It'll even reset itself and then trigger again if run long enough (Kent to Manchester twice is my main trips this year - for interviews).

Its painful because I either need to sell the car or use it and I can't do that right now.

Its had Audi history on it, so the water pump and cambelt were changed at 71k as per plan. If it had been the water pump I'd have expected some leak from that - but nothing.

I've checked the top hoses and they are hot, so the thermo is opening.

When run to normal temp and then parked the fan will run - even though the gauge is at a shade over 90 when running.

One other thing - I'm not sure if it is connected or not. The air con wasn't getting cold, I had Audi recharge it for those interviews (it was August, in a suit for 5hrs in the car - need air!). Still doesn't get cold. Then had to go to stansted on Saturday night in it - now doesn't get hot either. And by hot I mean the temp doesn't vary between low and high settings. Manually changing the centre vent setting will push the temp a little higher, but not much beyond luke warm.

On same journey I had a long wait in traffic on motorway, then 2 miles later the temp gauge spike to 120 ish, went back down to 90 quickly and stayed there.

I've heard the temp stuff is probably linked to heater control unit - not sure about the other stuff.

Lastly - sorry for a long post and for any noob errors.

Any help / advice greatly received. Especially those that lead to a cheap fix so I can exit the car and get some cash !

Matt