Three weeks ago I noticed a small puddle under my 61 plate Superb estate 1.8 TSI.   The next day, the red coolant light came on. It coincided with me getting new tyres fitted, so the fitters advised to just top the coolant up, which they did.   A couple of days ago, the red coolant light came on again. I parked up immediately and flipped the bonnet. It was 1.5cm below the min level, so yes, definitely a sudden leakage during the day when it had been parked up from 9am til 5pm