Electric water pump questions (hookup and power)

Edbert

Founding Member
Jul 13, 2002
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Austin TX
I am considering rewiring my water pump to only come on when my thermostat opens. This is due to not having any provision for a thermostat bypass on the waterpump. Is this recomended or a bad idea? Will I run the risk of damaging the pump if it runs with a closed thermostat? I don't think it would since the water pump has no outlet for a bypass. Maybe I should put a fitting into the lower hose for that?
 
edbert a fitting would be a good idea. It is to my understanding that the electric water pump is usually used on race-only engines. They dont even run a thermostat...you really dont need to run one either...i think thats why there is no provision for it on the electric pump.

I always thought it would be great to have an electric water pump and fan that run off a thermostat. They come on at a certain temp and shut off at a certain temp, even when the car has been shut off. :)
 
allcarfan said:
I always thought it would be great to have an electric water pump and fan that run off a thermostat. They come on at a certain temp and shut off at a certain temp, even when the car has been shut off. :)
That is exactly what I was planning on doing but I've received some negative feedback with the idea regarding the pump. I am using a 160 degree thermostat. I wanted both the electric fan and pump to be connected to an "always on" relay. The pump would be activated by a thermostat switch in the intake's water jacket to come on at about 180 degrees. The fan would come on shortly after than at around 190. Both would run once the engine was oss and the key was removed until the engine cooled to the point where the automagic switches would shut them off, no heat-sink for me. This is what I had been planning on doing. But I've been told that you must have "some" water circulation at all times to avoid steam pockets in the heads. This can happen long before the 160 degree thermostat opens too.

There are a few tech articles on Meziere's website that describe this phenomenon and I found one article that indicates that the best thing to do is drill two to four small holes into the thermostat flange to allow "some" water to bypass. See this photo found on an AHEM COUGH LS1 info forum:
130drillthermo.webp


By the way I did not get the race only pump, mine should be fine for street applications (so they say).
 

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