weak cooling fan
sunny1
07-25-2006, 07:40 PM
Hey everyone, This is probably just a dumb girl question but.... I have a 91 525I that has low miles and is a great car .... but when it gets hot out 105 or so if I run the a/c I loose all my water and my fan can be stopped while the motor is running.... if my car runs fine and cool while not using the a/c what could be the problem???? tia for any responses :banghead:
ShadeTreeBill
07-25-2006, 09:29 PM
There are two fans, one connected to the engine fan pulley by the fan clutch. This one spins under direct power from the engine fan belts. It can be spun by hand when the engine is stopped, Or I suppose you could stop it when the engine is running: this is due the it being attached through the clutch assy. The clutch can go bad, and this might be your problem: clutch too loose, fan doesn't spin at proper speed.
The second fan is electric and is located on the front side of the radiator. It is a little difficult to see, but if you get down on your knees and peer up inside the front grill of the car, with a flash light you can see it.
This electric fan is often the cause of a car that "overheats when the AC is turned on" since it is supposed to come on when the AC is turned on to provide the addtional cooling needed. There is a resistor mounted near the bottom of the fan that goes bad keeping the fan from coming on. This can be accessed and replaced by a handy person from underneath the front grill of the car.
It is controlled by a thermal switch that bolts into the side of the radiator (on my 89 525) and actually provides for slow speed, and high speed operation. There are also two fuses one for high and one for low speeds.
If you start the car, turn on the AC and look inside the grill and this fan is not running, then this is probably the cause of your over heating.
Of course there are many other things that can make car overheat....
This link might also help:
http://www.bmwe34.net/e34main/trouble/overheating.htm
The second fan is electric and is located on the front side of the radiator. It is a little difficult to see, but if you get down on your knees and peer up inside the front grill of the car, with a flash light you can see it.
This electric fan is often the cause of a car that "overheats when the AC is turned on" since it is supposed to come on when the AC is turned on to provide the addtional cooling needed. There is a resistor mounted near the bottom of the fan that goes bad keeping the fan from coming on. This can be accessed and replaced by a handy person from underneath the front grill of the car.
It is controlled by a thermal switch that bolts into the side of the radiator (on my 89 525) and actually provides for slow speed, and high speed operation. There are also two fuses one for high and one for low speeds.
If you start the car, turn on the AC and look inside the grill and this fan is not running, then this is probably the cause of your over heating.
Of course there are many other things that can make car overheat....
This link might also help:
http://www.bmwe34.net/e34main/trouble/overheating.htm
sunny1
09-15-2006, 05:38 PM
Thank you for your reply... My mechanic has been out of town for awhile and havent had a chance to discuss this with him.... but wanted to thank you and after his return I will get back to you with whatever he comes up with :tongue: Have a great day!
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