NHTSA Service Bulletin 11030636: 2018-2026 Mazda Cx-3

This Service Alert supersedes the previously issued SA(s) and TSB(s) listed below: The changes are noted in Red. SA-035/24 05/31/24 DESCRIPTION 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. This Service Alert is to inform you about the water pump sealing mechanism and the criteria if replacement is necessary or not. A mechanical seal (A) is used for the water pump. This mechanical seal can seal coolant (B) by sliding a mating ring (C) against a seal ring (D). When the sliding surface temperature of the mechanical seal is more than 248 F (120 C) while driving, a small amount of steam (E) is leaked and bleeds through the bleeding hole (F). After drying, the steam leaves a green coolant deposit near the water pump bleed hole (F). This is a normal condition and does not require water pump replacement. The water pump should only be replaced if there is an accumulation of crystallized coolant near the bleed hole. When you encounter a water pump with coolant seepage marks, decide to replace it or not based on the following criteria using sample photos. NOTE: During the initial period of use*, the sliding surfaces of the seals may not yet be fully settled, which can temporarily increase the amount of leakage. Continued use will allow the surfaces to settle, reducing the leakage. Replacing parts that are already settled with new ones will increase the leakage again until the new parts become conditioned. Therefore, replacement should be avoided in this initial period of use. *As a guideline, this applies to vehicles with less than 1,860 miles (3000 km) of mileage.