Hello, today I had first long trip in my 2007 a6 3.0 Tdi. It was all fine for most of it,but when driving back ( after about 200 miles) coolant warning light came on, bleeped few times and disappeared. So I stopped at the petrol station to check on my coolant level and it is fine. 2 minutes after I drove off it came back on again , this time it beeped like 3-4 times. Any ideas what could it be? 

Hello Edgaras,

Welcome to the forum and Audi ownership. 

Apologies for asking questions, but I take it you talking about the coolant level warning light and not a temperature warning light? 

If so, you should be able to feel an electrical connector under the coolant tank. Give it a wiggle and a squirt of WD40 and another wiggle, and see if that cures it. 

If not, it is likely that the level switch itself is at fault and will need replacing - not a big job. 

Perhaps you could let us know how you get on. 

Kind regards, 

Gareth.

When it comes on it just says Coolant under the sign and at the same time I feel a little loss of power And as soon as it goes power increase back to normal.I will definitely try wiggling that connector. Thanks

Just check what the handbook describes it as, but I'm pretty sure it's the coolant level warning.

In the handbook it says : Coolant level low/ coolant temperature too high. Press check button for any additional info about the fault. I have tried pressing check button, it checks all system and no additional info comes up.

Is it possible for the coolant temperature to be too high? If yes then what could cause that? 

Hello Edgaras,

I take it the car has a coolant temperature gauge - what temperature does/did it read when the light came on? 

Did you try the connector wiggling? 

Kind regards,

Gareth.

I did try to wiggle the connector, and today drove the car just short distances 15-20 miles. And no warning lights. When the engine warms up the temperature is always 90. But what I did notice is that when the engine is cold coolant level is between min and max marks,but when it's hot coolant level rises a little over max mark. 

Hello Edgaras,

It sounds as if everything is now spot on, and my feeling is that this was simply a dirty connection onto the coolant level switch. If the light comes on it may well be worth actually disconnecting the connector and contact cleaning the terminals, but that would be more easily done by removing the header tank retainers. In effect , if it does come on again it would probably be advisable to change the switch anyway. 

Coolant temperature is obviously fine at a running 90, and no doubt you keep a regular eye on this anyway - and more so if the warning light comes on again.

Coolant level - nothing wrong there. I tend to keep my cold (should be in capitals) level about half way between the Min and Max. marks, and as it gets hot, it may well rise  above the max mark.

All is well - let's hope the light stays out. 

Kind regards, 

Gareth.