Coolant escaping 2.0tdi

[rvtb101]

A coolant thread, I know, i know...but not on an S3... a 2.0tdi 184ps this time (14 Reg, 87k miles had it since 6months old - not a single problem, until now!)

The past couple of months coolant has been dripping from the car, escaping from the expansion tank. (Occured several times and had to top the expansion tank due to low coolant warning)

I took it to Audi, they pressurised the system and found no faults.

The leakages have continued to occur so I replaced the coolant tank and the cap as saw these were possible issues.

It is still happening! It appears to only do it during regens and I have noticed the fan does not seem to stay on when the engine is turned off after a regen like it used to.

I have checked fuses. Thermosats appear to be an issue with S3's. I have had the timing belt and water pumpt replaced a couple of years ago at 60k

Have any of you had anything similar issues - any remedies?
Thanks in advance, Rich

 

[Dubjam]

Have you checked the thermostat? That sounds like a thermostat sticking to me.

 

[rvtb101]

After taking it to Audi, they weren't 100% sure what was causing the issue but replaced the waterpump. This has stopped the car from gargling and the pump no longer whining. Great...until I took it to Cornwall,
All the way down the motorway (~180miles) no heating at all.
At slower speeds around towns I could either have HOT or COLD air with no real inbetween.
Air conditioning cools air, but doesn't aid in any heat.
Checked the settings in the MMI and the suppl. heater is set to Auto like it alway has been.
Coolant also fell below the low level marker over the 700miles trip, appears to have escaped from the reservoir cap. which is was doing before but not to the same extent or frequency before having the waterpump replaced.
Any ideas?

 

[rvtb101]

Heater matrix replaced. Heating now behaving normally and coolant seems not to be disappearing any longer! But...

My very right hand dashboard vent that blows on your right hand ALWAYS has a little air coming through it. Whether the button on the center control panel for dashboard vents is turned on or off.
When set on dashboard vents, this vent is never fully open like the others and it never closes (does not appear to move at all based on air flow)
Is this requiring the system to be recalibrated or is it a motor that controls just that flap not functioning correctly?
Any ideas? TIA