Why does a cars fan switch on (ie the engine fan)? for what reasons? I know its a simple question but im trying to get to the bottom of my car trouble. My car overheated and obviously the fan kicked in to cool the engine, but i have noticed it been on other times. is it usual for it to come on?
2007-01-30 20:55:23 · 10 answers · asked by Anonymous in Cars & Transportation ➔ Maintenance & Repairs
The fan is controlled by a switch which is triggered by the water temperature. If it gets too hot the fan will cut in. Regularly check the water level in the radiator, you may have a leak!!!
2007-01-30 21:09:58 · answer #1 · answered by McQ 3 · 0⤊ 0⤋
In the old days, the fan only turned when the engine was running. When the engine was switched off, it would remain hot for a long time afterwards since there was nothing running to draw cold air through the radiator fins.
Now all fans are electric. If your engine is running hot, the fan will usually stay on for a while to cool the radiator fins and bring the temperature down. There's a sensor that helps activate the switch to turn the fan on. If this sensor is covered in deposits, it can retain the heat for much longer and forces the fan to stay on.
You normally don't need the fan if you are driving along but if you get held up in traffic, then there is no airflow over the radiator and at a certain temperature, the fan will come on.
If your fan is switching on a lot, and you've already mentioned that your car overheated, you may wish to check if there's a problem.
If you top up the radiator expansion tank often, do you just pour in water or a mixture of water and coolant.antifreeze?
It should be a mixture. There's usually a ratio of water to coolant printed on the back of the coolant bottle - it's different for different seasons.
If it overheats it could also indicate a fault with the thermostat. This is a temperature sensitive mechanical valve that opens at a pre-set temperature to allow coolant from the radiator to flow into the engine block and keep the engine at an optimum temperature. If the engine runs too hot for too long, it damages the oil and can break or warp parts of the engine.
If the thermostat is faulty, it may not be opening properly, causing the overheat.
On really, really hot days, the fan can switch on because the heat builds up especially in a dark coloured car.
It's nothing to worry about unless you are experiencing a lot of overheating. Then get it checked out.
2007-01-31 10:48:31 · answer #2 · answered by Rob K 6 · 0⤊ 0⤋
It is normal to hear the fan in long traffic queues etc to aid cooling. It should not be needed just stopping at the lights. It is usually never needed driving along. The thermostat may be defective( a small job), or if the car is older and the cooling system neglected it may need flushing out with a descaler. This would be unusual. There is a remote possibility of cylinder head troubles, especially if the coolant needs topping up a lot. It really needs checking. Some of these problems will drag on then suddenly cause a spectacular and expensive failure.
2007-01-30 21:28:44 · answer #3 · answered by fred35 6 · 0⤊ 0⤋
the fan comes on for many reasons, engine protection. OR for Air conditioning. Some run with the key off to cool the radiator as well. basically its to increase airflow. the fan running does NOT mean its overheating, todays smaller frontal areas require lots of air flow over the smaller radiators. So the fan is required when the engine is working under a load. its usually set to come on at substantially less then overheat temps. Its NORMAL. expect it to run much more if not continuosly when AC is on. Replace the fan temp switch if your uncertain. verify your temp gauge, if possible. Good Luck.
2007-01-30 21:08:49 · answer #4 · answered by Gary M 3 · 0⤊ 0⤋
Some cars have the temperature sensor on the bottom of the radiator that turns the fan on when there is not enough air flow through the radiator to cool it down.
If your radiator is plugged up, or the water pump is worn out the slow moving water through the radiator cools off too much for the sensor to activate the fan.
I'd get it checked out befor it ruins your engine.
2007-01-30 21:12:03 · answer #5 · answered by Mr. KnowItAll 7 · 0⤊ 0⤋
That's normal for the fan to kick on,so that would not be the problem of your car overheating.
Try changing your thermostat, Also make sure your not losing antifreeze anywhere and check your belt to make sure it's Turing the pulley on your water pump.
You may also want to check the level of your antifreeze,Take the cap off when it's cool and start your car let it warm up and see if the antifrize is circurlating,if it is and it's full put the cap back on let it build pressure and look for a leak.
2007-01-30 21:13:54 · answer #6 · answered by Anonymous · 0⤊ 0⤋
The fan switches on when the tempurture reaches a set temp, to cool the raditor which moves hot water from the engine to cool in the raditor and then go around again, the common problem is the thermostat breaks and sets either on or off, either way is not good.
2007-01-30 21:08:33 · answer #7 · answered by Loader2000 4 · 0⤊ 0⤋
It could be that the thermostat is sticking and not letting your coolant flow through.I would try to change it out first.It`s cheaper than to assume that the Water Pump had went out.I call this the the easy affordable "process of elimination"
2007-01-30 21:15:42 · answer #8 · answered by spazz 3 · 0⤊ 0⤋
when your car engine reaches a set temp the fan will turn on.
Your problem maybe the water pump if it is leaking you need a new one.Most of the time they leak from the pump shaft or you hear a grinding noise.
good luck
2007-01-30 21:01:46 · answer #9 · answered by Normefoo 4 · 0⤊ 0⤋
its fine for it to be runin it only kicks on when ur engine reaches a sertain temp
2007-01-30 23:02:48 · answer #10 · answered by Anonymous · 0⤊ 0⤋