I would go the OEM, but I do not know of any better alternatives that have been proven? How many miles on the original? 100 to 200K would be considered good life in my book.

Here is one, you can have it by Tuesday if you order today Water Pump-New 2004-2006

BTW, SD is always a pleasure to do business with.

Most auto parts stores have the OM647 water pumps. Advance auto lists one for $97.00.

Thanks guys.

Looks like there are a lot of options and price variability. The GMB at OEM, although pricy, sounds really good, at least in the description. All OEM Car Parts - Discount Import Auto Parts and Accessories - 2004 Dodge Sprinter 2500 Water Pump
I have over 100,000 on the original pump. I bought my sprinter used about 3 years ago with 89K on it. It had been used as a cargo delivery van; I got it from the owner.

I converted it to a 'surfmobile': insulated it, put in a couch that folds out to a bed, sink, fridge, stove, counter top, pine cabinets, sunroof, 80 watt solar panel, 2, 100 amp gel batteries, etc.

Drove it back and forth from Texas to the west coast, up and down the coast, through the Sierra Nevada, spent 2 or 3 winters and a summer in Baja surfing and living in it on the beach.

I've had to replace the turbo charger, alternator, glow plugs, intercooler, plus regular maintenance.

It's ironic that I bought it because everyone told me a Mercedes diesel would run forever trouble-free. In fact I've spent more money fixing it in 3 years than the combined cost of my previous car (a Toyota) plus maintenance for 11 years.