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Fan Not turning on when car heats up

3K views 26 replies 11 participants last post by  polaris448 
#1 ·
Well, I just got my car back from being re-built, because it overheated. Spent about 2,700 to fix entire engine and clutch setup. Well the car moves great, I love it. But this overheating thing is really getting to me. After getting the car back from shop, let the car sit at a light while I made a call, noticed the needle starting to move to hot. Opened the hood and the fan was not on. Turned the AC on the fan kicks up and the needle dropped. OK so Temp sensor has to be bad. Ordered one from the Stealership for a good price about 50 bucks. Jumped the fan to low speed until it got in. Problem with jumping fan is car stays cool and no heat inside. Ahhh Finally got new sensor replaced old one. However I let the car sit for about 20 minutes and fan never turned on. Car did not overheat but I didnt want to wait until it did. Any clues on what this could be, its driving me crazy.
 
#4 ·
ok guys get this shit, when i let me car run for more than like 8 mins the neddle starts climbing and never stops till i either start moving or it over heats. Once i start driving the heat plumits and goes back to normal. My fan also doesnt ever kick on when im parked but you would think if you car was gonn over heat it would come on. Its been like this for about 2 weeks and i know its not a good thing to be driving it but i dont have a choice and cant afford to dump anymore money into this car. So is it the fan, the thermostat or the tempsensor? Please help me. Thanks lot. Bob318
 
#5 ·
Well, I recently got the car rebuilt new Water Pump new Radiator new Thermostat, new everything pretty much, so.... The only thing I didnt replace was that sensor, so I bought it and it still doesnt kick the fan on. I think its kind of silly that it will only turn on when the car is moving. So the car will overheat and not attempt to turn the fan on. I dont know that doesnt really make sense to me. Any other ideas?
 
#6 ·
Ok, first of all teh fan will turn on any time the thermostat says it should. If it did not turn on while your car was sitting still your car would overheat quite quickly. Infact the fan does not run that often when you are moving because there is enough air moving through your engine compartment that the fan has nothing to do.

I would check and make sure that the thermostat was installed properly. If it is not the thermostat then it could be the fan itself. But these problems are usually the thermostat.
 
#7 ·
Word man, thats what i was thinking. It would be so lame if the fan just didnt turn on when you wernt moving. That would be so worthless. My fan doesnt turn on at all. Ive never let it over heat but it get up to half way on the gage when its 15 degrees outside in less than 5 minutes when im not moving.Its bad news.
 
#9 ·
One cheap way to do it would be to mount a $5 switch on your dashboard and turn on the darn thing whenever you wanted it on.
 
#10 ·
There are 2 fans right? The belt driven fan attached to the waterpump shoudl spin all the time.. this is the fan that does most of the cooling. The other fan (aux fan) only turns on when the A/C is engaged or in extreme heat where the engine needs that little extra. Now, which fan are you reffering to that doesn't spin?
 
#11 ·
Yeah I was thinking about putting a darn switch, just mad that I've paid so much already, and still that darn switch dont work.

To answer your question 93 I only have 1 fan the one in between the motor and radiator, I dont have this AUX fan in front of the radiator, in fact I never had it.
 
#12 ·
Should be two fans...

Are you saying you only have one fan, an electric one, its behind the radiator, and its not coming on? Someone removed your belt driven fan that's normally mounted on the motor? If that's the case, I would reinstall the belt driven fan and put the factory installed aux cooling fan back behind the grill the way the car was designed.






Mike
 
#14 ·
I only have one fan inbetween my motor and my radiator. I dont know waht you guys are talkin about 2 fans. Are you sure they had the aux on 95 and older? cause mine doesnt have one. Im finaly just bringing my car in on friday so if i figure it out ill let you know.
 
#15 ·
An electric puller fan behind the radiator is actually a much more desireable setup than the factory belt driven fan. A company called Trimline makes a great fan to put there, cools better than factory and frees up the pully system.

Hamfisted said:
Are you saying you only have one fan, an electric one, its behind the radiator, and its not coming on? Someone removed your belt driven fan that's normally mounted on the motor? If that's the case, I would reinstall the belt driven fan and put the factory installed aux cooling fan back behind the grill the way the car was designed.






Mike
 
#16 ·
My fan has nothing to do with me pullys. Its just a big electiric fan. Im kinda assuming that the fan is just burned out.
 
#17 ·
did you have them install the fan or did some one else have it installed? There could just be a wiring problem with the fan. If it was in there before they might have disconnected something and forgot to reconnect it. Or if it is a newly installed fan then other installation or quality control errors could be coming into play.
 
#18 ·
There should be a big fan infront of your engine, connected to the waterpump! and there is no switch telling it to come on, there is an oil bubble in there and when it gets hot it expands and flicks it on, but yeah the water has to be flowing trough you water pump, so im also guessing there is something wrong with the thermostat, unless the waterpump stuffed up again! Try moving the fan with your hands, not spinning it but moving it up and down, if its loose at all the waterpump is screwed! and the fan should always be spinning freely with as the water flows trough the water pump!

the other fan, the ac one im guessing, is smaller and you can probably see it trough you grill at the front, before your radiator!


my mechanic said its a very complicated systerm but very efficient once its working properly!

if i said something wrong please correct me!

good luck! i used to have the same problem! and once one thing goes out in that system you generally need to replace everything!
 
#19 ·
ONLY ONE FAN GUYS! PAY ATTENTION NOW PLEASE! NO PULLY! ONE ELECTRIC FAN THAT JUST DOESNT TURN ON ANYMORE! Two fans is nonscense. I have one big fan behind the radiator and thats it.
 
#20 ·
Hey Bob318 Since me and you have the same car mines is a 96 and same problem, I thought I would shed light to what the problem was for me, since its finally been repaired. Turns out I replaced all parts remember water pump radiator thermostat new Temp Sensor. What it was was the plug that goes to the temp sensor has a ground wire and a low speed and high speed wire. The low speed wire was traced and was spliced, So the fan would never turn on low, only when I jumped it. I would trace your wires just to double check, I just got my car back from the mechanic, and me and him both could not believe how much trouble we went thru for a silly little wire.

AND YES I only have one fan, not pulley driven but an electric fan controlled by a temp sensor plugged into the radiator. Hope this helps.
 
#22 · (Edited)
bob318 said:
ONLY ONE FAN GUYS! PAY ATTENTION NOW PLEASE! NO PULLY! ONE ELECTRIC FAN THAT JUST DOESNT TURN ON ANYMORE! Two fans is nonscense. I have one big fan behind the radiator and thats it.
Please refer back to my last post, it's along the lines of Redbullrr's.

If the fan worked until they did replaced all of the above material, they prolly did not reconnect the fan properly, unless they were the ones to install the fan in the first place. What you have is not stock, therefore a mechanic that did not install it orginally might not know exactly what to do to make it work. Check all the wiring before replacing the fan.
 
#23 ·
check this shit out. This blew my mind. So i put the ac on and pop my hood to check this worthless fan out. The fuckin fan runs high speed for like 15 seconds and then one of my pullys stops turning and my fan shuts off. Then 15 seconds later my car revs and the pully spins and so does the fan on high. Then it shuts off and does the same thing. This keeps up every 15 seconds till i turn my car off. Keep in mind this fan is electric and has nothing to do with any of the pullys. Seriously what the hell is going on. Do i need to replace this pully for some reason or somthing along those lines? This is by far the lamest thing i have experinced with this car.
 
#24 ·
Thanks red. Ill check that out. Is the heat sencer the thing thats hanging byhind the fan that looks like a small thermomiter?
 
#25 ·
Hey Bob, its just a plug on the corner of the radiator. But in your case it sounds like your fan clutch is bad. You said it spins and then stops. Thats strange... I posted up on the other page the details, here you go.

If your facing your car on the left hand side on the top corner of the radiator is a plug that screws into the radiator. The part that screws in is the Temp Sensor. The if you look at it connected is a 3 wire plug. This 3 wire plug is for your radiator fan. It has a brown, green, and black cable. Black is for ground I believe brown is for low, and green is for high speed. From the clip trace the wires and see if there are not spliced.

I tested my car yesterday and let it sit on with the heat blasted. AND Yes the Fan kicked on and my car no longer has the heating problem. WOO HOOO.
 
#26 ·
I found this thread today in a search.

Some 318's do not have a belt driven fan at all. Ony one electric fan behind the radiator. realoem seems to indicate that 318 with M44 engines have the electric fan. Just pointing it out as it seems not everyone knew about it. The Bentley manual says the M44 with manual tranny is electric only. Just pointing it out as it seems not everyone knew about it.
 
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