I had asked this before, but got no responses - wondering what is the difference, mechanically, between an expensive GM water pump and a cheap one fron NAPA or Autozone- other than the GM lifetime warranty ?
Price. I’ve had good service with aftermarket waterpumps. No one wants to be nailed to an answer if you should use an aftermarket waterpump, and it should fail. Then, what would we hear? “But, YOU said that they are just as good! Therefore, you gave bad advice!”
Well, just to generalize, the GM part is brand new from their parts manufacturer that uses the exact same process and QA as the parts used in the factory. Essentially a true factory part. The less expensive part from NAPA or Autozone is either remanufactured, which is a rebuilt part from a failed part, or new from a different manufacturer than GM uses, and probably lacks the same exacting QA process. They should be able to tell you if it is a new part or re-man. Typically, a re-man will want the old one back with a core charge, so they can re-man and re-sell it.
There is a consensus that the GM part is better and has a much lower probability of premature failure. But, typically the NAPA or Autozone part has just as good or better warranty, with a lot of Autozone replacement parts have lifetime replacement warranties as well. They still make enough profit on the part to cover replacements of the ones that don’t hold up.
I have only had one re-man part fail prematurely on me, but it was an easy replacement in my Toyota truck. I used Pep Boys, and they replaced it for free. I could have still purchased 2 re-mans for the price of the one OEM facotry pump. I still feel I came out ahead.
was just looking for expertise on the part itself - already got one installed at GMC dealer - just wondering how one could be half the price of the other - plan on keeping the truck as long as I can (it only has 62K original miles) so the lifetime replacement may be handy , thanks
Typically, a remanufactured water pump consists of the bearing(s) on the impeller shaft being replaced.
You have to remember that pumps fail due to that bearing wearing out, and the water seaping out of the pump body, and being flung everywhere.
Seen as how the water pump from GM varies in how long it lasts, that shows that their bearing quality from their OEM supplies varies greatly.
Does Napa use a better supplier for the exact same size bearing?
That’s completely unknown.
I would not hesitate to get a rebuild from NAPA, BIG A, PARTS PLUS, ALL PRO, CARQUEST. These guys sell quality auto parts. I never buy items like these at AUTOZONE OR ADVANCE, there is a difference in quality.
NAPA, BIG A, Krager (aka, Checker and other names depending on what part of the country you’re in)-- all of their rebuilders check water pump casings for cracks and other abnormalities. And every after-market auto parts place knows that there is an inevitable failure rate in any rebuilt part. Stuff happens. Even OEM parts have a failure rate, though it’s lower than aftermarket parts. So getting a known good rebuilt part from a known good store is not much different than an OEM part—except in price and warranties. I, too, have used NAPA, BIG A, CHECKER, and especially Car Quest parts and have not experienced a difference in failure rates. In fact, I’ll state that with all of the rebuilt parts that I have used, water pumps, starters, alternators etc., that I have had only two ‘bummers’. One Toyota rebuilt alternator, immediately and without question replaced by Checker and one bad straight 6 Chevy water pump, also immediately replaced without question by Car Quest. So take that for what it’s worth to you. Just another old wrench’s experiences.
I’ve found that Autozone, Advance/Checker/Shuck’s/Kragen and other parts stores that cater more to DIY-ers tend to have a tier of parts cheaper than the cheapest parts that you can get at a place like NAPA that does more wholesale buisness. For a DIY-er, whose time is theoretically free, it makes more sense to put in a cheaper part since the warranties are usually the same, so if it fails you’re just out some of your own time. With a professional mechanic, the correlation between time and money is clearer and when a part fails prematurely, he has to waste time he could be billing replacing it, not to mention he’s going to have to deal with an angry customer.
However, the DIY stores usually do stock parts comparable to what the others have, you just have to ask for them. With something that’s easy to swap out, I don’t mind taking a risk on a cheaper part.