Hey everyone, I've gotten tired of replacing failed water pump gaskets on my small block chevy. One issue with the SBC design is the mounting and sealing of the water pump. It's common to use RTV on the gaskets. The problem there is that the force applied to the gasket when the bolts are torqued can cause the gaskets to split and be forced out from between the pump and block, then you have a leak. This is made worse when using an aluminum pump. The aluminum is smoother and doesn't retain the gaskets as well. The most common failure seems to be at the bypass on the bottom of the passenger side of the pump. I have learned to use Permatex Aviation gasket maker and apply it to only one side of the pump. This leaves one side just paper and the gaskets seem to hold better. The last time I resealed my water pump, I used sand paper to rough up the sealing surfaces of the pump as well to improve gasket retention. I have the Edelbrock Victor pump installed on my 355 and it's been a great pump. The problem is that it has lasted so long, it outlives the paper gaskets.

If you ever replace a water pump on an LS motor, you'll see that GM changed their gasket design from the cheezy paper of the SBC to gasket of soft aluminum with rubber printed sealing rings around the passages. This has proven to be a much better design and if the cooling system is maintained to prevent corrosion, the gaskets will last the life of the vehicle, or at least the life of the water pump. The next time I have to install a water pump on one of my small block chevys, I plan to visit Gasket Specialties in Portland and have them produce a set of aluminum water pump gaskets for me, with or even without the rubber printing. I think the aluminum, whether printed with rubber or or lightly coated with the aviation sealer, will hold up alot better in this application.

 

I've never had this problem with gaskets, and I've put a lot of WP's on a lot of SBC's. Probably because most engine's I've worked on were not high strung performers.

Not to be rudimentary, but would it help to re-torque the WP bolts after several heat cycles? And yes, all the gaskets on LS type engines are awesome, and in most cases re-useable.

 

I quit using RTV on water pumps some decades ago, due to poor performance and outright failure of various sorts. It's just not the right stuff for the situation at all. Or for that matter, any similar situation, where the parts vibrate ALOT and otherwise move, and the silicone tears into little pieces and turns into little *****. Head bolts are another such place; RTV is GUARANTEED to fail, on those.

I use something that stays somewhat soft and that can move without tearing; Permatex 200 (brown gooey gunk with a brush), that purple stuff, something like that, even gorilla snot sometimes; and the "high-temp automotive pipe thread sealer with Teflon" on the bolt threads. NOT "Indian Head" shellac (dries hard and crusty, doesn't remain soft & pliable) or the like even though it's brown and goes on with a brush too. Haven't had a WP gasket failure in a VERY long time, with that combo.

But still, I like the idea of incorporating late 20th century technology into the mix. Gotta be better than the WW2 "slap it together cheeeep by the millions" approach.

 

Those LS water pump gaskets have been know to leak, its a common problem.

 

Actually, I see alot of the LS engines in trucks. The only WP gasket failures I generally see on these engines, are due to lack of cooling system maintenance or adding tap water to the coolant. It's corrosion that generally causes the WP gaskets to fail. At least this has been my experience. In any case, the coated aluminum gaskets with no added sealer make replacement a snap. It's a 2.5 hr book time job that barely takes an hour. So much easier than scraping and cleaning to reseal the SBC WP gaskets. And don't think that I'm a big fan of the LS motor. I'm not at all. I'm only touting the newer gasket technology.