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Recently, I have been experiencing a couple of weird Fan issues with my 05 MCS.
Symptoms are like this:
If I am sitting in a parking lot for like 10 mins or so, heater on or off, A/C Off, radiator fan kicks in. Its pretty loud. The fan only runs for a short period time and turns off then it repeats.
However there is ANOTHER loud and noisy sound that comes along. It is so loud I thought my car was having a serious issue. It is definitely On - Off interval like the radiator fan. But it usually stays on alot longer and weird thing is when I move my steering wheel, and hold it in a position, any position but center neutral, the sound goes away.As soon as I let go, the loud noise comes back.
So here are a few things I have checked out tonight..
.
.
1) Radiator fan speed - High Speed kicks in for sure when A/C is on. Seems like Low speed doesn't.
2) PS Fluid - It is definitely topped
3) PS Fan - It kicks in well when the A/C is on.
I am a little scared to run the car, even though it does not overheat or anything... I mean, the fans all still works fine, and does not act up unless I am sitting around idling for 10 minutes or so.. what harm can it do?
Any insights will be greatly appreciated..!
Thank you in advance!
The problem with your car is that the low speed is not working. Low speed should engage at 105c and go off at 101c.
When low speed works it is adequate to cool the radiator and high speed will not come on.
If low speed fails high speed will kick in at 112c (the car will stumble and recover fairly quickly due to the massive amount of current required to run high speed)
The fan on the power steering pump also runs when the radiator fan is in high speed.
To verify this use an OBD scan tool and monitor the ECT parameter; you will find it goes to 112 centigrade then the fan runs.
The high wattage resistor mounted on the fan shroud has likely burned open. This resistor provides less amperage to enable the low speed function.
You will also find that the A/C blows warm air due to the low speed failure.
The fan has to be replaced!
Good luck and I hope this helps!
__________________
In the abundance of Water only the fool is thirsty!
The problem with your car is that the low speed is not working. Low speed should engage at 105c and go off at 101c.
When low speed works it is adequate to cool the radiator and high speed will not come on.
If low speed fails high speed will kick in at 112c (the car will stumble and recover fairly quickly due to the massive amount of current required to run high speed)
The fan on the power steering pump also runs when the radiator fan is in high speed.
To verify this use an OBD scan tool and monitor the ECT parameter; you will find it goes to 112 centigrade then the fan runs.
The high wattage resistor mounted on the fan shroud has likely burned open. This resistor provides less amperage to enable the low speed function.
You will also find that the A/C blows warm air due to the low speed failure.
The fan has to be replaced!
Good luck and I hope this helps!
Wow. Great Post. Clears up the all the questions!
So even the other loud noise that is controlable by turning steering wheel is related to the radiator fan??
Oh and YES! The A/C didnt blow so cold during the summer times!
Thank you Very much
I have re-tested radiator fan's low speed and it is dead for sure-!
Another thing was I have pulled out the Power steering fan to clean and inspect. Everything worked as it should.
However, I believe I read a post regarding PSF (Power Steering Fan)'s operation...
1) Is it suppose to be on ALL the time?
2) Is it suppose to be on when I turn my key to ON position (The click right before ignition) ?
3) Is it suppose to be only ON when the engine is all warmed up? (I.E. Off if weather is cold and I am doing cold start.. etc)
Well the PSF unit itself did not seem too bad. It does not turn on when the engine is on (cold-start) / does not turn on when the engine is warmed / does not turn on when ignition is turned to ON position BUT! It turns on when A/C is on.
Any thoughts on that? Oh and also, the weird noise beside high speed radiator fan I have been hearing seems to be coming from the fan..
Well, an update with a few more questions eh? I guess its better than nothing
The answer to questions 1, 2 and 3 is: The fan on the PS pump is hard wired to the high speed of the radiator fan.
Therefore the PS fan will only run when the radiator fan is commanded to high speed.
There are two occasions when this will be true: the coolant temp reaches 112c or/and when the A/C is turned on and the freon pressure is high enough to satisfy the pressure switch.
__________________
In the abundance of Water only the fool is thirsty!
The answer to questions 1, 2 and 3 is: The fan on the PS pump is hard wired to the high speed of the radiator fan.
Therefore the PS fan will only run when the radiator fan is commanded to high speed.
There are two occasions when this will be true: the coolant temp reaches 112c or/and when the A/C is turned on and the freon pressure is high enough to satisfy the pressure switch.
Thank you for confirming that it does not run all the time
[quote=frenchie;2641458]
Quote:
Originally Posted by sprp85
I have tested a few more things out today!
I have re-tested radiator fan's low speed and it is dead for sure-!
How did you test/determine it was dead?
For the testing, I started the car in the morning. cranked up the A/C and waited. I read somewhere that when A/C is on, no matter what, low speed will activate..well that did not happen so............. I thought as it is quite cold this time of the year, maybe the low speed will kick in as the car warms up- well, the low speed did not kick, only the high speed fan every 20 secs or so! So I can assume that the low fan is at fault No?
Thank you so much tho. I see you helping out many others with similar problems lately! or maybe not so lately..
Same exact thing was confirmed for my '05 MCS with 55K miles. Unfortunately the problem went undetected long enough for it to take the A/C compressor with it.
Yesterday afternoon I suddenly lost my A/C. I talked to my independent mechanic right away and he said to bring in the car today. He did the same exact tests Frenchie described in his post and low and behold the fan's low speed is not working. The fan is only working at high speed, therefore, the engine is running hotter and the A/C compressor was also running at max pressure. This problem eventually killed the compressor (As confirmed by the A/C test gauges when turning on the compressor the high pressure gauge barely moved and hot air coming from the vents).
I am upset that the dealer did not detect this issue when I last took the car to them in mid-December. Would have been a perfect opportunity to replace the engine fan as they replaced the clutch and it would have also been covered under warranty.
So now I am looking at a new A/C compressor and new engine fan. This will be at least $1,300 repair bill But what can I do? I need the A/C. Yesterday we had temps in the low 90s
So I left the car this morning with him. He has a new replacement engine fan in stock but needs to order the compressor. If he can get a hold of the compressor, he'll have the car ready this afternoon, if not, it will be ready tomorrow.
The way I look at it....$1,300 still beats buying a new car with warranty. I love this car and keeping it in tip top shape is well worth the money IMHO
By the way, my friend tech told me that the low speed engine fan is a very common failure in these cars (He does at least 3 per week, that is why he keeps the part in stock) and the fans tend to go south by the time the car reaches 50K-60K miles, so keep an eye on it if your car has the factory fan still in place.
Quote:
Originally Posted by frenchie
The problem with your car is that the low speed is not working. Low speed should engage at 105c and go off at 101c.
When low speed works it is adequate to cool the radiator and high speed will not come on.
If low speed fails high speed will kick in at 112c (the car will stumble and recover fairly quickly due to the massive amount of current required to run high speed)
The fan on the power steering pump also runs when the radiator fan is in high speed.
To verify this use an OBD scan tool and monitor the ECT parameter; you will find it goes to 112 centigrade then the fan runs.
The high wattage resistor mounted on the fan shroud has likely burned open. This resistor provides less amperage to enable the low speed function.
You will also find that the A/C blows warm air due to the low speed failure.
The fan has to be replaced!
Good luck and I hope this helps!
__________________
'08 R55 Cooper S Clubman - HC/S
'05 R53 Cooper S - CR/W
Already replaced on power steering unit on my 03 including the PS fan. Still question the operation of the PSF on hot days or in traffic?
Gets way to hot under there even before the radiator fan kicks in. So I've decided to splice into the circuit and add a switch in the cockpit for manual PSF operation as well. Easy enough to do with it being hard wired to the radiator fan!
No? 
long enough for it to take the A/C compressor with it
.
But what can I do?
I need the A/C. Yesterday we had temps in the low 90s
04 Cooper S / Stock / Sport Package / cold wthr pkg / Navigation / Aux Input
