Hizeternal

Hello there everyone. I recently bought a 1999 Audi A6 2.8 Quattro and I noticed that the climate control won't turn on when on the auto setting no matter what temperature I set it on. It's 44 degrees F here and another thin I noticed is that after 30 minutes te engine temp is still on C all the way over left. Also to mention I have a check engine light on and need new brake pads.

What could be wrong? After looking at various topics here my educated guess would be the thermostat is dead. If so would that cause a check engine light? Would that affect both the auto on climate control and the engine temp?

The climate control works, when placed on manual, fans a everything work. But I did notice it wasn't heating up to a satisfactory temperature.

LR Audi

Congratulations on your purchase. Did you get a pre-purchase inspection or do anything research on the vehicle's history? A faulty thermostat does not throw a CEL code. If your thermostat requires replacement then it is a very, very tedious job that most backyard mechanics would avoid, and labour wise it is very expensive. You may as well do the entire timing belt/waterpump/tensioner/seal kit to save yourself from future issues.

The brake pads, both front and rear are very simply to accomplish. The rear requires a special disc brake tool that you can rent at many parts stores if you do not wish ti purchase. I strongly recommend replacing the rotor at the same time. Check my brake pad review to see what I recommend. I have new brakes front and back and everything in total would take me less than four hours with basic hand tools.

If your AUTO switch is not turning on, it may be the HVAC controls themselves. However, if your engine temperature still says COLD after driving for an extended period of time then your thermostat is most definitely failed. You'll be using far more fuel than you need to as your vehicle is dumping more fuel to compensate for the colder operating temperatures.

Hizeternal

Thank you for replying! I thought I was going to be left in the cold forever. I did research the vehicle history but didn't get a prepurchase inspection...yes I know but the people I bought it from is family and I didn't pay much for it. He said it could be a sensor or something causing the CEL. I do plan in getting an inspection soon but wanted to trouble shoot a little.

As for the HVAC the auto turns on (the light comes on) but the fans cut off as if the temperature is reached. I can do manual and put the fans on high and they work, but little to no heat. Hit auto and fans turn off and stay off no matter the temp. 77...88...doesn't matter no change and outside temp was 44F. I read, later after making the topic, I could flush the heat core with water and get some gunk out that could be causing the problem before a jump into installing a thermostat.

Now back to the CEL, engine doesn't slip as far as my knowledge goes and tiptronic works like its supposed to. The light is steady lit and not blinking which is a good thing, right? But yea I need to get it inspected to get it registered and so want to fix anything that would fail it.

LR Audi

Regarding your CEL, there are so many sensors that would set it off. It can be emissions related, powertrain related, even collision related. I'd recommend tracking down someone with a Vag-Com to scan your car for you, or shop around and see who charges the least amount of money. I purchased mine for about $400 and it has saved me a lot of money.

I don't really use the AUTO setting on my HVAC controls butv they are meant to maintain a certain temperature in the cabin, which is why they turn off once that temperature has been reached. If you don't have enough heat in your cabin and your engine temperature gauge reads COLD then you definitely have a thermostat failure. If you look at your engine oil temperature gauge (lower left hand side) it should reach operating temperature regardless of your engine temperature gauge (top left hand side).