Cooling System - Small Water Pump Leak Explanation

Bulletin No: 01-004/09

Last Issued: 02/03/2009

Subject:
REPLACEMENT OF WATER PUMP FOR COOLANT LEAK

APPLICABLE MODEL(S)/VINS
2003-2009 Mazda6 (with 2.3L, including Mazdaspeed6)
2004-2005 Mazda Miata
2004-2009 Mazda3 (including Mazdaspeed3)
2006-2009 Mazda5
2006-2009 Mazda MX-5
2007-2009 Mazda CX-7

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 Bulletin is to inform you about the water pump sealing mechanism and the criteria if replacement is necessary or not.





A mechanical seal is used for the water pump, and this mechanical seal can seal coolant by sliding a mating ring against a seal ring. When the sliding surface temperature of the mechanical seal is more than 248°F (120°C) while driving, a small amount of steam is leaked and bleeds through the bleeding hole. After drying, the steam leaves a coolant leak mark on the water pump. This is normal, and the water pump should not be replaced. The water pump should only be replaced if there is an accumulation of crystallized coolant around the bleed hole.

When you encounter a water pump coolant leak concern, repair the vehicle by referring to the repair procedure.

If you confirm a coolant leak from steam bleeding, explain to the customer that this is normal as explained above.

REPAIR PROCEDURE





Water Pump Coolant Leak Repair Procedure

1. Verify customer concern.

2. Verify repair.





Water Pump OK: No accumulation of crystallized coolant

Water Pump NOT OK: Accumulation of crystallized coolant.