radiator fan stays on

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i got a 94 civic ex coupe... i just swap a 94 LS engine into it... for some weird reason the fan just happens to stay on, so the car is always cold.... once i unplug the fan from the radiator support the engine gradually warms up... then the idle drops down severely!!!! then another thing is the engine bogs out at low RPMS when i try to take off... i changed the spark plugs, spark plug wires, distributor, fuel filter and i even changed the damn TPS and still the engine wont open up at low RPMS.... can anyone help me!
yup it just stays running! as soon as i turn that key, that fan comes on and stays on untill i shut off the car.. which isnt too bad but the damn motor is always cold!
i dont see why the engine would always be cold just cuz the fan is always on..
because the coolant circulates in the block until the engine gets up to operating temperature which is when the coolant goes to the radiator and the fan brings the air through the radiator cooling the coolant(in simple terms).
if the engine was always cold, then it would be really bad.
i agree fully with green, the reason your engine has a thermostat is so that the motor will reach a higher operating temp. "controlled" higher temps let the motor run on less fuel, produce less emissions and cause less internal wear. by controlled i mean not reaching the point of diminishing returns (overheating) and beyond the threshold of the cooling system.

my guess is whoever did your swap (you?) wired up the fan incorrectly or the new motor's coolant temp sensor is shorted. but that's the lesser of your two problems. if your motor had a thermostat in it, the fan running all the time would not prevent the car from getting to temperature, again, like green stated. remove the thermostat housing and put a thermostat in there. then if you desire to do so, check the resistance across the two pins of the coolant sensor (the one in the thermostat housing you just removed) with the motor cold. then again once it's up to temperature. if the reading is the same, or anything like 0.1ohm, the sensor is shorted, replace with a known good sensor.
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