fredc125

So, I'm in the process of replacing my 1985 13b water pump. I have pulled the pump housing for inspection. As I stare into this housing and try to imagine how the flow is directed it seems like something isn't quite right. Just under the thermostat there are two passages. The passage in the center directly under the thermostat connects directly to the passage of the other radiator connection. So basically the in and out of the radiator come together immediately inside the pump to the same side of the impeller. A channel through the engine block also joins at this same area while the other end of the block circuit winds up alone on the other side of the impeller. Seems to me that this pump spinning in either direction would certainly not be flowing all of the water through the block then through radiator as one complete circuit. Obviously the factory design works and is the way it is for a reason. I just don't see how it makes sense. If the two radiator connections effectively come into the pump at the same place , wouldn't this create a cancellation of direction and pressure. Now if the one hole directly below the thermostat was plugged, then it would all make perfect sense. Is the thermostat itself part of this equation? I was told to run without a thermostat. Is that a big mistake? Any body out there have any thoughts here. I would greatly appreciate them. Thanks.

fredc125

After searching for hours I've finally figured it out. Yes, the thermostat is a vital part of the system. It will close off that hole and allow the system to make sense again once it has warmed up. Thanks anyway.