Sbc Water Pump Gaskets Continue To Blow Out After Replacing All Associated Parts,3 Motors,3 Pumps, Who Knows Y
Posted in Internal Engine Parts | Asked on Jul 10, 2010
Water pump gaskets blow from between the pump and block.I have done the following:had 3different engines,2 sets of heads,2 intakes,3 water pumps, tried new bolts with new lock washers,used studs instead of bolts,with loc-tite,new lock washers,even double nutted studs, made bolt retainers similar to header bolt retainers,tried double gaskets, tied no gaskets with permatex,made gaskets from header gasket material,made gaskets from other cardboard materials,even went as far as placing a piece of 1″ pipe in the water jacket to prevent pressure from being directly on the gaskets,drilled 3/8″ holes in the pump impeller blades to prevent pressure,drilled holes in water pump mating surface that correspond to the holes I drilled in the block and installed 8 small screws into,and ground the heads off so they would go through the gasket and into the pump different thermostats,no thermostat with only a restrictor,different pulleys,tried under driving WP.they only blow after a hard run,over 6000rpm
There are 3 Answers
The surfaces are not matting up. A gap between the engine and pump is causing this. Check the surface on the engine for low places and be sure all the old gasket has been removed. It may have to be resurfaced. But sometimes you can use JB WELD to fill in the gaps or heavy on the silocone sealer on both sides of the gasket. Be sure to let the sealer dry over night before putting coolant in the engine.. If all else fails, use an exhaust material to make a gasket. They are reinforced with metal. Hope this helps
Master tech 40 years
three things come to mind, the first is a radiator cap, sounds stupid but seen it before. also there could be a pinhole in the lower radiator hose, when you run hard it sucks air and makes too much pressure. your not going to like number three. a stock style water pump is not meant for racing, you may have to get a electric one that is.
i own a repair shop,and i have seen the problem your having before,it was caused by way to much pressure on the cooling system of the engine,and it was caused by someone putting the head gaskets on wrong on it,i know it sounds way to simple on it ,but this is what i found on one i did,the owner had changed motors and decided to replace the head gaskets to save from having to do it in the future,he had also replaced the ones on the original motor,and both were wrong,but that was what i found on one,,maybe this will help you some,good luck,