Audi a4 coolant leak
Hi everyone, I have a 2017 Audi A4 V6 3.0 272 that’s been coming up with an intermittent switch off engine and check coolant warning. The coolant tank when I checked it the buoy was well under the min line. It’s gone to the DSA centre in Sheffield who have investigated (£90) and said that they pressure tested and the water pump is not holding any liquid so they said it needs replacing, I also told them to put on a new auxiliary belt as a preventative thing…. they were taking the old one off anyways.
When I got the call to pick it up I started the car and the coolant light was back they topped up the coolant saying it’s an air lock after driving around 50 miles the coolant light is back intermittently and I ha checked the coolant tank and the buoy is well below the min line again.
Also they put on new brake pads and discs and since driving it the car has been making a knocking noise over bumps and when I come to a stop and have my foot on the brake there is no sound as soon as I lift my foot off the pedal the knocking noice occurs again.
Any advice would be greatly appreciated……what could be causing the coolant leak and is it on the garage for miss diagnosing and also what should I do tomorrow as I need the car for work?