1979 water pump

[Gary Smith]

I have a 79 L48 that I just got out of storage. I think I hear a slight rumbling noise by the fan,and I can move the water pump pulley slightly, maybe a 1/16th of an inch. With only 30k miles do I need to replace the water pump and if so can I get it rebuilt quickly by someone (? any reccos?) or do I need to replace it outright? Do I need to take the fan shroud off too?

[Michael W.]

Re: 1979 water pump

Best change it right away. Buy a quality rebuild and use that while your original core is off being rebuilt. Some guys redo their own, it's not rocket science if you have the tooling.

You shouldn't need to remove the shroud.

[Paul L.]

Re: 1979 water pump

I would replace the pump before it leaves you stranded. An AC Delco dealer will have one (or access to). You do not have to remove the shroud (see pic).

[Joe L.]

Re: 1979 water pump

Gary-----

I'd replace the waterpump. Generally, the 71+ pumps will last a lot longer than 30,000 miles, but you also have the "age factor" going here if the pump is original.

You have several choices. You can send the pump you have off to someone like Arthur Gould in NY. He'll rebuild it for you and send it right back. However, obviously, there will be a delay of at least several days in transit, alone.

You can also purchase a rebuilt pump at an auto parts store. Very likley, you will get a correct casting waterpump (GM casting #330813) since there were only 2 castings ever made by GM for the 71-82 Corvette small block waterpump and the L72 to 82 casting (the one you need) is, by far, the most common. A rebuilt pump will be fairly inexpensive. If you go this route, don't give them your original pump for a "core"; the core charge will be only a few dollars, anyway.

You can also purchase a brand new pump from Delco. It will have a generic casting, though, and won't have the original casting number. Otherwise, though, it will be 100% functional and will appear very close to the pump you'll be removing. The GM # is 12458924 which is also known as Delco #251-501.

[Eric Roberts]

Re: 1979 water pump

Gary, I just finished replacing the water pump on my '81 yesterday. Although mine had significantly more miles on it than yours the symptoms were the same. Change it. A rebuilt unit can be purchased for around $40-$50 or an aftermarket can be purchased for $30-$40 --- go figure. The shroud does not have to come off but I did find it easier to change with the air filter and snorkels off.