AS benzmac says most aftermarket water pumps are not upto OE quality. In the past MB sold only new pumps at a real $$$$$ expense. But w/rebuilt parts they don't cost any more than aftermarket. The only aftermarket pump that uses OE bearings & shaft seals are "Graf". No matter who builds the pump they all die sometime. Have replaced hundreds of pumps under warranty!! Some after 1 year & others after 5.
MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. TECH
190E 2.3 ITS RACECAR