I purchased a 2012 Passat 1.6 diesel in May 2015 from a Volkswagen dealership. In January 2015, the low coolant warning light came up on the dashboard. The coolant was topped up, the whole system was checked and no leaks were found. However, within two weeks, the same issue occurred. Again, it was topped up and checked. No problems were found.

The level stayed within normal range throughout the summer and now as it got colder it has dropped significantly below the minimum. Couple of days ago I turned the air con on by accident (while the temperature was set to about 23C) and switched it off within five minutes. As soon as I did so, a very bad smell came out of the vents.

Please advise me on what could be causing such issues as I will have to fight to get the car repaired under warranty which has run out in May of this year. I have made it clear to Volkswagen Customer Services and my local dealership that as the issue was not resolved I will be seeking free repair under warranty as the issue was reported before the warranty expired.