That Mazda Water Pump Might Be Just Fine
Mazda notes that some water pumps are being replaced needlessly on models including 2020 CX-30, 2016-2020 CX-3, 2013-2020 CX-5, 2007-2012 CX-7, 2016-2020 CX-9, 2004-2005 Miata, 2006-2020 MX-5, 2004-2020 Mazda3, 2006-2015 Mazda5 and 2003-2020 Mazda6 vehicles. There is a concern that some water pumps are being replaced that are not faulty due to signs of a very small coolant leak from the bleed hole.
A mechanical seal is used for the water pump. This seal can seal coolant by sliding a mating ring against a seal ring. When the sliding surface temperature of the seal is more than 248 degrees Fahrenheit, a small amount of steam is leaked and bleeds through the bleed hole. After drying, the steam leaves a green coolant deposit near the bleed hole. This is a normal condition.
The water pump should only be replaced is there is an accumulation of crystallized coolant near the bleed hole.