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Music and Hot Rods
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Discussion Starter · #1 ·
Got a 388 that runs great and doesn't really overheat, but it has an electric water pump that kinda worries me. I've got a 180* stat in there now but the electric fan control turns on at 200 and off at about 180*. So, usually, once it turns on it never shuts off. I was thinking I may go to a 160 engine stat and change the fan control to a unit that is on at 185* and off at 170*. That way while cruising faster than 30mph or so the fans will be off. I know this means my temp will cycle between 185 and 170 at low speeds, so would this 15* temp cycle cause any problems?

I'm also wanting to go with a high flow stat because the electric pump is always at the same flow. When i run on the dyno or make a good hard road pull the temp rises quickly and takes a bit to come down.
 

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Here's something to remember for all car guys who watch the temp gauge more than they watch the road:
Most all temperature sensors for the gauge are located near the thermostat housing. So what are you actually seeing on the gauge?
Well as the coolant circulates throughtout the motor, it picks up heat from internal metal surfaces. So it keeps moving picking up heat and as it passes the sensor it will register the temperatur of the coolant.
BUT.....here's where everyone gets crazy with seeing the gauge..........the coolant is at it's hottest is leaving the motor. You are not gauging the temp of what's in the motor.You want a motor to run in the 190-210 range for making max HP. You run a motor too cool and you are not burning the fuel totally and you can have excess gas wash down the cylinders.
If the fan,pump, and radiator have done their job, the coolant coming back into the motor on the bottom hose should be 15-20 degrees cooler............but again, you are not gauging those temps.
Stop watching the gauge and enjoy the drive..........and firebird is correct..........electric pumps are for race cars, not the street.
 

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Music and Hot Rods
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Discussion Starter · #3 ·
Here's something to remember for all car guys who watch the temp gauge more than they watch the road:
Most all temperature sensors for the gauge are located near the thermostat housing. So what are you actually seeing on the gauge?
Well as the coolant circulates throughtout the motor, it picks up heat from internal metal surfaces. So it keeps moving picking up heat and as it passes the sensor it will register the temperatur of the coolant.
BUT.....here's where everyone gets crazy with seeing the gauge..........the coolant is at it's hottest is leaving the motor. You are not gauging the temp of what's in the motor.You want a motor to run in the 190-210 range for making max HP. You run a motor too cool and you are not burning the fuel totally and you can have excess gas wash down the cylinders.
If the fan,pump, and radiator have done their job, the coolant coming back into the motor on the bottom hose should be 15-20 degrees cooler............but again, you are not gauging those temps.
Stop watching the gauge and enjoy the drive..........and firebird is correct..........electric pumps are for race cars, not the street.

I understand this, but since the pump was on there when I took ownership, and it's working fine for the street I thought I'd leave it there. My questions were more about the fans than the pump.

With my current setup, the fans are supposed to turn off at 180* but since the stat is a 180*, and we all know that stats and fan controllers have some tolerances, once the fans turn on the temp never gets cool enough for them to sut off. Even on the hiway the fans run. Since I've never had any great experiences with adjustable fan controllers, I thought if i dropped to a 160* stat and a controller that shut off at 170* my fans would not be running on the hiway.

As far as effeciency at temps, I made my first dyno pull at 180*. At the end of that pull the temp was at 230*, so, I idled the truck with some huge blowers running good aie thru the rad and got the temp down to 200*. I made the second pull and lost about 35 hp and 44 lb/ft, I'm assuming from the higher temp. Now, as I said before, I think this is because of the stready coolant flow from the elecrtric pump, and was wondering if a higher flow stat would help the temp spikes on a hard pull.
 

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First thing is all t-stats open at there given temp........but they are not full open till 15 degrees above said opening.
So a 180 opens at 180 but it is not full open till it hits 195.
Also another thing about your temps on the highway. With an electric pump only pushing X number of GPM(gallon per minute)the pump cannot help cool the motor when it is running at speed like 60mph. When doing 55-60 mph , the motor is making more hp to move the car at said speed. And more HP = more heat but the pump is still only pushing the same GPM as if you were at idle. Taht's why with a belt driven pump you can increase the pump speed with RPM, electric pump can't.
The fans do have some leeway in tolerances and some do come on at given temps but I have also seen them vary plus or minus 10-20 degrees. It's something you will just have to live with.
 

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Discussion Starter · #5 ·
It's not a big deal, really. Hiways temps range in the 185 to 190 range which is fine with me. I just don't care for the iddea of the fans running constantly, AND, i don't want an over ride switch. Too easy to forget.
 

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Change the water pump , Sell it you will get your money back for the new pump & few extra bucks for GAS!! Your motor will thank you in the long run. Keep it and down the road i smell head gaskets or maybe a total rebuild! Your truck Your choice!
 

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Music and Hot Rods
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Discussion Starter · #7 ·
I've got a nice Stewart pump sitting here. Maybe I'll stick that on there, but that still doesn't stop my fans from running all the time.
 
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