Fans running when engine off.

[Rockape63]

Hi All

This is a bit of an odd one as its something that occurred a few months ago, disappeared and then cropped up again this week.

I had just locked my 53 A4 3.0 quattro cabrio sport and was walking away from it, but stopped upon hearing a very quiet whirring noise from the front low left of the engine bay (as you stand in front). I decided it was nothing to worry about, but returned at the end of the day to find the battery completely dead.

Managed to jump start it and when I got home I could hear it running so disconnected the battery. This continued until it was checked and they found a fault code for the main fan (which this one isn't) and no further issues. Then a few months later, I came out of my house to hear the main fan running at full power making a lot of noise. To cut a long story short it killed the battery and I jumped it again and could hear the small fan running to disconnected the battery and booked it in. However, since running around for a couple of days I decided to leave the battery connected as the fan seemed to have stopped and now its all back to normal again.

I know if I took it in, they would find a fault code and nothing else, so would then suggest replacing parts in the random hope that it would solve the problem....which of course would be impossible to know until such time it either did or did not happen again!

So, does anyone have any thoughts/ideas on this?

[mikeybutch]

It might come back so I would go for diagnostics.Could be a faulty sensor which is an easy fix

[Rockape63]

It might come back so I would go for diagnostics.Could be a faulty sensor which is an easy fix

as I mentioned the diag check showed a fault with the main fan, which then was okay for a few months. It doesn't show anything about a smaller fan which appears to be the main issue.

[mikeybutch]

I would have it checked again .