overheating > fan coupling > how to change

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slinky2000
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Sat Feb 16, 2008 6:27 pm

Right, the sport went up to about 3/4 ont he temp guage today in traffic and I've never seen it that high before, It never went above half even when stuck in traffic on a hot day.

Anyway, I can stop the fan with my hand so I presume the coupling thats the cause of the problem. coolant seems to be pumping ok and heaters work fine.

I know its just a big nut but do I take off the rad in order to get access? Is it just a simple swap job?
Last edited by slinky2000 on Sat Feb 16, 2008 6:34 pm, edited 1 time in total.
kam-325i
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Sat Feb 16, 2008 6:30 pm

First Qustion........

What engine is it ?
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slinky2000
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Sat Feb 16, 2008 6:33 pm

sorry m20 2.5
kam-325i
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Sat Feb 16, 2008 6:37 pm

Ok.....

Is an easy job.

The rad can stay on. If you have the cowling on the rad, this wil have to come off.
Just unscrew the big nut off the water pump, there is enough room between the rad and fan to pull it out. just remmember its a left hand thread.
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slinky2000
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Sat Feb 16, 2008 6:45 pm

ok thanks I'll have a look tomorrow to see :)

when you say "Just unscrew the big nut off the water pump" does the pump need to come off?
kam-325i
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Sat Feb 16, 2008 6:47 pm

No. The pump will stay where it is. The end of the pump shaft has the thread on the end.
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slinky2000
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Sat Feb 16, 2008 6:48 pm

got ya! cheers :)
slinky2000
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Sat Feb 16, 2008 6:55 pm

bmwe30mtech
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Sat Feb 16, 2008 7:00 pm

The way to do it is a hard sharp hit with a hammer (on the spanner). Force is not what is needed, and as said, remember its a reverse threaded nut.
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topspark
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Sat Feb 16, 2008 7:03 pm

kam-325i wrote:Ok.....

Is an easy job.

The rad can stay on. If you have the cowling on the rad, this wil have to come off.
Just unscrew the big nut off the water pump, there is enough room between the rad and fan to pull it out. just remmember its a left hand thread.
As Kam said above its quite easy . 32mm spanner required IIRC.

have fun.
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Sat Feb 16, 2008 8:00 pm

correct it is a 32mm spanner, i did this job today, piece of p1ss, took 10 minutes, it takes longer to unscrew the 4 bolts that hold the fan to the coupling than to actually take the thing off.
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duke_rattlehead
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Sat May 03, 2008 3:57 pm

sorry to ask this question as its probably been asked to death, but how do you stop the water pump shaft from rotating when you try to undo the 32mm nut? I have tried cable tying the fan belt and wedging a spanner on the pulley but neither are strong enough to stop it rotating.

EDIT: with the use of mole grips and a BFH it came off quite nicely 8)
slinky2000
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Sat May 03, 2008 6:40 pm

lol nice one mate, I just got my machenic to do mine while he was doin a few other jobs.
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