Other S80 Problem: Radiator fan not malfunctions, car overheating

[charlie44nike]

Please i need help. My radiator fan does not kick in on time, it works like it has a mind of it's own. I always have to turn my airconditioner on before the fan blows.

The car is overheating, its a 1999 Volvo s80. I have called a mechanic in my country Nigeria, and they said they have to relay the fan to work direct, which means they have to hotwire the fan to the battery, it wouldn't work with the thermostat anymore.

Please i want to know if this proposed method will not have any effect on water flowing into the engine when the thermostat won't be working anymore.

Please someone help me before i ask them to proceed.

[JRL]

Has the thermostat been changed? Is it faulty?

[charlie44nike]

Originally Posted by JRL

Has the thermostat been changed? Is it faulty?

I don't know if the thermostat is faulty. In Nigeria, the mechanics advise to hotwire the fan, so it works once you start up the car. I just want to know if that is a good idea

[cheshired5]

Originally Posted by charlie44nike

I don't know if the thermostat is faulty. In Nigeria, the mechanics advise to hotwire the fan, so it works once you start up the car. I just want to know if that is a good idea

It's a bad idea. You'll burn out the motor.

[Brendan W]

Fan works, good.
The fan has two calls for it. The aircon needs it to get the condensor some help and the motor needs it to cool the coolant. Clearly the fan is still talking to the aircon but the motor isn't.
The problem could be that the temperature sensor is not working. Generally this would produce abnormal reading and throw an error. One way to test is to disconnect the temp sensor and see if the car responds with a temperature warning lamp and putting on the fan.
Another possibility is that the sensor is ok but and is calling for fan but the earth from the fan relay is open and the ecu cannot fire the fan relay.
I would have thought that aircon and coolant use the same relay to fire the fan, maybe not.
There were issues with earlier cars of fan control units acting up.
The proposed modification is a standard enough bodge to fix this kind of issue. You can get thermostatic switches to strap to a coolant hose to mimic the effect of the cars sensor.
I would avoid all of this like the plague on a car as sophisticated as the S80.
When you say the fan has a mind of it's own could you be more specific. How long does the car take to get to normal operating temperature ? How stable is the temperature gauge needle ? When it overheats do you get a warning, where is the needle ?

[charlie44nike]

Originally Posted by Brendan W

Fan works, good.
The fan has two calls for it. The aircon needs it to get the condensor some help and the motor needs it to cool the coolant. Clearly the fan is still talking to the aircon but the motor isn't.
The problem could be that the temperature sensor is not working. Generally this would produce abnormal reading and throw an error. One way to test is to disconnect the temp sensor and see if the car responds with a temperature warning lamp and putting on the fan.
Another possibility is that the sensor is ok but and is calling for fan but the earth from the fan relay is open and the ecu cannot fire the fan relay.
I would have thought that aircon and coolant use the same relay to fire the fan, maybe not.
There were issues with earlier cars of fan control units acting up.
The proposed modification is a standard enough bodge to fix this kind of issue. You can get thermostatic switches to strap to a coolant hose to mimic the effect of the cars sensor.
I would avoid all of this like the plague on a car as sophisticated as the S80.
When you say the fan has a mind of it's own could you be more specific. How long does the car take to get to normal operating temperature ? How stable is the temperature gauge needle ? When it overheats do you get a warning, where is the needle ?

Thanks for the update, but i dont understand a lot about cars. This is my first car and i dont want to use it for practice. When i say the fan has a mind of its own, i works whenever it likes. The The temperature gauge it in the middle in less than 5 minutes and remains here for a long time before it overheats. And when it overheats, i get a warning because the needle leaves the middle and goes to the high side of the gauge. The car takes a few minutes to get to normal operating temperature. I am frustrated. I don't know what to do.

[Brendan W]

Does the overheating happen in town traffic or on the open road ? I'm guessing town traffic.
Can you find the temperature sensor plug and disconnect it with the motor running.
What engine is in that car, we might be able to tell where it is if we knew.

[charlie44nike]

Originally Posted by Brendan W

Does the overheating happen in town traffic or on the open road ? I'm guessing town traffic.
Can you find the temperature sensor plug and disconnect it with the motor running.
What engine is in that car, we might be able to tell where it is if we knew.

The overheating happens on the road, it has never happened in traffic. I don't know the temperature sensor plug. I don't know what kind of engine is in the car, how can i know the engine type? and as for the sensor, i don't know what it is. I am scared of putting my hand in the whole engine compartment so i don't do something wrong.

[jasmith44]

Is it petrol or diesel engine (car )?

[Simon Jones]

The fan runs at a number of varying speeds depending on the conditions. Often is going round but you don't hear it because its not running on full blast.