I own a 2015 Q3 with c.40k miles on it. Purchased a year ago from Audi. The car recently overheated. Upon inspection, I found two small canisters IN the coolant tank with small granules in the canisters. One of the canisters had broken open so I assumed that the granules were now in my coolant system. The mechanic had to replace the water pump and thermostat due to both a leak and clogging by the granules. Our assumption was that the canisters/granules were a cheap fix for an existing leak, prior to my purchase.
I spoke to my Audi dealership and they told me that the canisters are normal and that Audi put them in ALL their coolant tanks! No one I have spoken to and none of my research has found anything about these canisters.
Does anyone here know anything about these mysterious canisters that I found in my coolant tank and if Audi do actually put them in, and why?!