Hello all,

new poster here.

I’ve had my 2017 audi A3 2.0 diesel for nearly 7 years, and been a great reliable car. However I noticed a coolant leak in December, my regular garage could not find a leak but they said they saw coolant staying at the bottom pulley and suspected leak or weep from water pump. Advised I monitor for a couple of weeks and come back if still leaking which it was. They recommend replacement of the water pump and timing belt which has been done but the leak is still ongoing. Doesn’t anyone have suggestions as to what else could be causing the leak?  I’ve spent nearly £1k on this issue so keen to narrow down possibly causes without endless trips and costs taking back to the garage.

thanks in advance. Rob 

It could be the egr cooler leaking, but something as simple as a failed expansion tank cap. This you wouldn't notice. Linked to this water could be escaping out of the expansion tank where the two halves of it are joined if that makes sense. 

Both of these parts won't be that expensive to change. Whereas egr cooler will be. 

Welcome Rob,

Has anyone carried out a coolant pressure test on the car?

How much coolant is it losing in say 200 miles? 
One simple cost-free test to do, is to take the car on a good run of at least 20 miles.

Immediately on your return, get a glamorous assistant to rev the engine at a steady 2,000 rpm for 3 minutes while you observe the exhaust - looking for any white smoke. 
Please report back with your findings.

Regards,

Gareth. 

If the coolant level is dropping but there is no visible leak, then the leak must be internal, in which case I'd agree with Steve's suggestion of EGR cooler.