I am having trouble with the heat. Usually on a cold day I leave the car on for a few minutes in a parking lot to warm up, and it works pretty quick. Recently the problem started where the car would not warm up when idle. Then after I drive it for a while, the fans start to blow hot air and as soon as I stop on a stop light it turns to cold air.

Does anybody know what the problem could be? Is it a stuck thermostat?
The coolant temperature indicates normal 90C, but my engine oil temperature gauge seems not to be working as well.....could that be related?

Thanks for your help in advance!

 

Start with a VAG scan to check for codes. Could be the Coolant Temp Sensor or a few other things. If no codes are reported and based on what you describe, it's likely the thermostat.

 

Does anybody know if it is a big job replacing a thermostat on a 2.7T? Approximately how long should it take to replace it?

 

Thermostat is under the Timing belt. I wouldnt jump to conclusions yet. My climate control spits out cold air only on the drivers side once in a while, passenger is always warm. Maybe somthing in there.

Also, I thought a bad thermostat has reverse symptoms. Cold while driving, and warm when stopped (no air cooling the rad at a stoplight means warm water in the heater core) Come to think of it, that almost sounds like a water pump problem your having - more than a thermostat.

 

How many KM's on your 2.7T? Maybe it's time to consider doing the full TB Kit with Thermostat and Water Pump. The reason I suggest is the labor to access the water pump or thermostat is the same, which also means the T-Belt has to be removed so why put the old one back on. I installed the ECS Ultimate 2.7T TB Kit a year ago and am happy with it.


If it is the thermostat, depends if it sticks open or closed as both scenarios are known to occur. It is more common for an Audi T-Stat to start failing open causing cold engine while a less common fail closed T-stat causes an overheating engine.

 

I replied to a similar problem presented in the A4 section. My daughter's '99 A4's heater was not blowing warm air, and I ended up reverse flushing the heater core. It was full of cellulose fibre (gasket material?) and black silicone. I wrote up a quick how-to, and it seems to be fine now. Quick and easy to do, it is my suggestion to reverse flush the core first, before spending any real money. The heater core is a high point in the cooling system, and acts as a "filter".

turbine guy