Been playing with a waterpump for my 304 that needs a few mods before fitting so I stripped it down today to see what I'm working with. I pressed all the bits out and found this...
You can see how badly the bore has been galled up where the bearing assembly was pressed in, one has to wonder if the assembly was in straight? if not than I can see that leading to seal failure if the shaft isn't running true in the bore/seal assembly. I'm not sure If I'll continue with this pump as I don't want to waste more time and effort on something that may fail quickly. Don't think I can send it back for warranty either....
I was under the impression those pellets were a stop leak additive first and foremost. Our L67 is still on it's original waterpump going on 17 years and 238Km and hasn't had the factory recommended coolant in it since I owned it. Our previous VS I replaced the pump and it ran till it was scrapped many years later without issue also without the factory recommended coolant, I even considered pulling the pump off to keep as a spare as it still felt as smooth as butter.
So I recently changed the waterpump on the L67. Done over 243,000km. Pump still feels like new? It is either the original pump or the pump was replaced by a Holden dealership because it's a genuine GM pump and not some after market replacement. It also still had a genuine gasket with rubber inlay etc, no sealant used which suggests original pump to me. Hopefully the new pump lasts just as long.