2003 Suburban - Need Water Pump

Mar 17, 2011
It looks like I have a leak originating from my water pump behind the pully.
2003 Suburban 1500 5.3 2wd.
From what I understand, water pump problems are common on these vehicles. I had mine replaced once already, not sure what it was replaced with.
I am looking for recommendations of an available pumps that might be a good replacement option. AA sells Delco Professional for 200.00, which seems way overpriced when comparing to RA, but I don't have time to wait on RA shipping.
I see a Gates on Amazon for 72.00 with 1 day delivery.
Dealer is 300.00
Looking for options that are available in stock so I can get back on the road. Anything I should stay away from?
I would consider OE, but they seem to not last either.
Is AC Delco Professional line O.K?
I have a gates on my 2005 suburban with about 18 months and 11k on it. No problems. Another thing I did is the entire truck is on Prestone with Core-Guard/Motorcraft Yellow coolant.
It's looking like my only options local in stock are AC Delco Professional or Napa...Other than Duralast and Carquest.
The ACDelco "Professional" line is actually inferior to the "GM Original Equipment" line.

I have a 2001 Silverado 5.3 that was leaking around 80,000. When I got it apart, I realized the gaskets were leaking, not the pump. Fooled by the name, I had ordered the professional pump and changed it since I already had it.

The replacement started leaking--from the weep hole--after about 38,000. (It did take nine years, but the original pump went twice the miles in that time.) This time, I replaced it with the Delco GM Original from Rockauto.

Here's what I ordered:

Water Pump: ACDelco 12703898
Thermostat: GM Genuine 1511057
Heater Hose Connectors (2): Dorman 800-409
Cap: ACDelco RC98
Gaskets: Fel-Pro ES73010 (The pump should have gaskets, but my experience made me wary of the stock ones.)

Depending on your thermostat style, you might need to order a new housing and thermostat for the later style pump. My original had the "integrated" stat and housing. The newer one allows the stat to be replaced separately from the housing, and apparently the pump is a bit different.

The heater hose connectors are on borrowed time if you've never changed them. When I did the first water pump, I actually couldn't get one to fit (great Dorman Quality) so I left the original on. It disintegrated a couple years ago. Yours may be different if you have rear heat. There seem to be more options now than when I last ordered, including a metal Dorman piece and plastic ones from other companies.

Amazon has the Delco pump for about $10 more than Rock if you think it will get to you faster.
AC/Delco original is what I run if I have to replace them on any of my LS stuff. Usually the gaskets fail. The only failure I have had was when I dropped the WS6 pump during the cam install. I cracked it. I replaced the one on my last truck when I had it off to do the gaskets. The AC/Delco is a good unit.
I'd go with a NAPA premium or whatever their most expensive one is. If you have an AAA membership, NAPA usually gives a discount.
ACDelco GM Original Equipment from Rock Auto. They do offer express shipping options that will still keep the total cost reasonable :)
The wp in our old '05 Yukon failed. It was the funniest failure I've ever seen. Only knew it was bad because it was screaming but NOT leaking. On the 5.3 there's a huge flat just above the water pump, it'd be a spacious patio for a couple Star Wars toy figures (ok I'm exaggerating a bit) and it had actually spit a single roller bearing up onto that land, but never leaked.

Anyway I think I used whatever O'Reilly had at the moment. We sold the vehicle shortly after so no longevity report. It's an easy job -- even easier in '05 with electric fans....I think '03 was still engine driven fan?
If I had more time for shipping, I would have definitely gone with OE Delco online but I need Suburban for work tomorrow.
Ended up with Napa. The only one they had in stock. They said it was Gates with lifetime warranty. Turns out it is GMB with lifetime warranty. It is an easy job, so I can always change it later if needed.
Thanks for the feedback.
NAPA changed from Gates to GMB for water pumps sometime in the last 2 years. I have Gates water pumps on 3 different GM vehicles (actually 2 now that the 99 Silverado was stolen 2 weeks ago) that have been in service for 7 - 10 years without any problems. Our old 99 Silverado had the NAPA branded Gates pump on it and it was the factory gaskets that failed on the original water pump.

I know nothing about GMB water pumps long term reliability.