I stand here in front of you, asking, or perhaps more correctly, needing the help and collective knowledge of the Audi Sport forum users!
I, for my sins currently have an 08 plate sportback, 1.9tdi (105 - about as exciting as dishwater). Have gone in the past through a series of VW's and Audi's the current chariot was bore out of the necessity for economy. One day I will rebel, but until that time I just need to fix the bloody thing!
So, in late June the car went in for a replacement DMF and Clutch.
On collecting the car, I drove it 3 miles home.
I left it overnight and the next morning drove it approximately 10 miles. After around mile 3 I noted the temperature hadn't risen. Odd, but not impossible. By mile 9 it still hadn't risen and indeed didn't come off the stop for the journey. I rung the garage in dismay and arranged to take it straight into them to get it checked over.
They VAG-COM'd it and produced a fault code for the ECT sensor. Based on the simplicity of the job I assumed it was an annoying coincidence and agreed I'd change it myself. A couple of days later I changed it for a pattern part ECT from EuroCarParts. The problem persisted and the Engine Management Light had by this time come on. The gauge would occasionally work, but never rise to temperature and more often than not it didn't work at all. I rung the garage who cursed me for using pattern parts and told me I needed a genuine sensor, so I replaced it for a genuine sensor - Nothing. They checked the fault codes again - this time there was a fan code (small fan) as well. They also suggested it could be the second of the ECT sensors in the rad, so this was replaced - Nothing. I suggested Thermostat based on a posting here, they suggested I didn't know what I was talking about and said it was likely a problem caused by a fan module which might throw up odd codes. Indeed the fan was running all the time the ignition was on, so it made bleeding the coolant a problem! The next port of call was the fans, so two new fans later and the problem still persists (albeit the fan code has now gone away). They checked the codes again and it now has codes:
000280 - Engine Temp Sensor
00003 - Control Module (which they are suggesting could be the cluster itself?)
I have insisted that the Thermostat is changed which apparently they've done this afternoon and the problem still persists.
I am concerned that this issue originally arose just after the 'box had been out of the car, given that all of the above elements are on the 'box side of the engine bay could something have been pulled or knocked which is causing the issue?
Does anyone have any thoughts on the problems that present themselves? I'm tempted to get them to try another Thermostat in it (I think they've just tested the old one rather than replacing it) anyway. They also mentioned some 'lugs' or 'pins' in the thermostat housing which apparently can degrade and cause issues? Is that correct?
They want to throw a cambelt, aux belt and waterpump at it now as they are concerned its impeller failure on the pump - doesn't seem likely to me?
On top of the DMF and Clutch this is proving an expensive exercise and I can see them trying to move the issue away from the timing with the 'box removal.
How common is cluster failure on these? VAG COM is giving readings for both temp sensors now so we're confident the sensors are working which is part of the problem!