SBC V8 Water Pump Failure, 3 Styles of Pumps Tested BYPASS THERMOSTAT UPDATE Options

[nick mironov]

My Renegade water pump failed yesterday. The pump impeller is stamped steel and the blades all just folded over or sheared off. I understand that the cast impellers are much stronger, but that not all manufacturer's cast models will fit into the Renegade housing. Anybody have experience with cast impeller pumps that will fit into the Renegade housing?

Since there is no bypass in the Renegade system, Renegade instructions are to limit the motor RPM to 3,000, or less, untill the thermostat opens. I have observed this, but the pump still failed after 5,500 miles. Renegade now makes a bypass kit, which I going to try, but I would still like to get a more durable pump.

Nick

[SLITS]

Ok, last bit of information I will post on this.

First, the GMB pump is the cheapest piece of crap on the market. Rebuilders will not touch their castings as the metallurgy, QC and such is just to shabby for a reliable rebuild. Secondly, they use cermaic seals which can crack and leak at the blink of an eye if subjected to cavitation.

I won't address the poor quality of the stamped steel impellers. The buying public demands inexpensive and that's exactly what they get.

As far as the seals / bearings going out ... The seals on a water pump were designed as a secondary pressure outlet. If the thermostat doesn't open on excess pressure, the seal will and weep water. If it is leaking, something else is wrong in the system.

Bearings will fail due to excess tension on the pulley. Remember, that pulley is side-loaded (kinda like spacing rims out causes wheel bearing failure) and that is why the manufacturers specify a specific tension.

As I was told, a water pump can be built to never leak, but was designed the way as they are as a secondary pressure relief in the system (just like freeze plugs, etc).

Be aware, all pumps can have their problems, but the impeller blades of a cast iron pump do not bend nor disintegrate (unless you don't renew your coolant) Coolant (ethylene glycohol or even propolyene glycohol) breaks down into two organic acids under heat. These acids go after system metals and especially like aluminum.

You can choose whichever pump you wish. All this thread has done is expose exactly what the pumps are. I am not the expert here ... the gentleman I ask questions of has 40 years in the water pump rebuilding industry.