A3/S3/RS3 Common Faults
Plastic clips on the regulators failure is quite common, causing the window to stop function correctly.
Cat Heat Shield
The bolts holding the shield on rust off and this will cause a rattling noise.
Plastic collars snap off, need to be replaced with the updated part from Audi.
The plastic impeller fails which can cause damage to the thermostat. This needs to be replaced with the metal water pump to prevent this issue.
Backup battery in the alarm siren
A sign for this is 3 beeps from the rear passenger side before the siren goes off. This is fixed by removing or replacing the alarm siren.
Roof Rail Conversion
Sealant along weld line that joins the roof to quarter panel breaks down and allows water ingress and hence corrosion
Respray done by Audi if car is under 12 years old and is well looked after.
Clutch Slave Cylinder
This can fail leading to fluid leaking over the clutch. When the flywheel is replaced the clutch will need replacing too. Also if the clutch fails before the slave cylinder, its probably worth replacing the slave cyclinder at the same time.
Coolant Temp Sensor
Early models used a black sensor which was prone to failure, this will cause rough running as well as the temperature gauge becoming erratic. This is repaired by replacing the sensor with the uprated green sensor.
When test driving look out for a slipping clutch, if it does it will mean a knackered clutch/flywheel. Test this by putting it in a high gear and going full throttle, if you get lots of revs and no movement then it will more than likely be a slipping clutch.
Hesitation at high revs
This is down to shot coil packs, dodgy spark plugs or faulty injectors.
Poorly finished alloys
Some wheels had poor finishes and eventually suffered with lacquer peel. This is cured by a good quality wheel refurbish.
Many A3’s this shape are still in the dealer network and many are still under warranty so it is difficult to see about any real common problems. If you have any for this shape please add it here so everyone can see!