Just how long is any machine supposed to be reliable?

It IS a 2003. It is now 2007. That's four years in Chicago weather. Water pumps fail - go to a parts store and see how many they carry for late model engines and how many more they can get in a day. Every manufacturer sells many water pumps.

Pretty soon she's going to need a battery too. I get anywhere from 4 to 7 years on a battery. Does that make the ML a bad car?

Does she get it serviced to schedule? That in itself would probably not have prevented a wp failure. Or maybe it would - when was the last time she had the antifreeze replaced with the proper antifreeze?

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Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport