How do you unbolt the viscous fan? What have I done wrong?

[Jesus325iTouring]

My viscous fan shaft is shot,it's wobbly and clearly not in good shape.
I can't work out how to unbolt it,I see there is a big bolt on the shaft itself,this I assume has something to do with undoing it,however as the shaft is all wobbly,I can turn it easily by hand.

Can anyone shed any light as to what has happened? It feels like the shaft is attached to fresh air but it won't pull out.

Cheers,Rog

[Jesus325iTouring]

Ah,upon contiued search using the search function I v'e found how to remove it,32 mm spanner and some elbow grease.
However,as the complete shaft is loose does this suggest the pump is gone? If so,how the hack does it come off?

[Topblag]

Hold the belt and turn the nut the opposite way from normal, when it's loose, spin it off by hand. Store the fan upright - can't remember why, just do !

[Jesus325iTouring]

Will do

[CaesarBob]

Water pump comes off with 3 bolts into the crankcase. Trouble is the timebelt tensioner is also fitted to the water pump so you'll need to retension that if you change the pump.

Not sure how old your belt is but i think its recommended that retensioning an old belt is a no-no. I'd check it out first and get some better advise.

[Ziggy]

Yup, M20 water pump is a cambelt-at-the-same-time job. Not particularly taxing though!

Where is the play? If the pulley moves you need a new pump, if the fan wobbles but the pulley stays still it's the fan coupling at fault.

[daimlerman]

Reads like your waterpump is shot,there should be no play in that shaft!
Drain coolant
Remove radiator
Remove drive belts
Place an old drivebelt around the waterpump pulley and use a bar of some kind as a torniquet(sp!)to hold it securely whilst you get that 32mm nut slackened,remember that this is a 'reverse' or 'left hand' thread.
Top cambelt cover off,and any other bits in the way.
Set the engine so the crank/cam marks line up(22mm spanner on the crank bolt)
Remove the cambelt
Unbolt the waterpump,three bolts,one is cunningly hidden behind a casting web.


I would replace pump,cambelt,viscous unit and both drive belts whilst it's in bits,and bung fresh antifreeze in as well.Also,flush the radiator and block out with your hose pipe.
Have fun,it will be at least half a day's knuckle grazing...

[Jesus325iTouring]

Guys many thanks for your replies,new parts on the way

Malc many thanks for your step by step guide,this will be a BIG help,it'll be copy and pasted onto my arm in biro

Incidently,the play in the shaft is 10mm all directions,it's proper knackered!

[daimlerman]

Incidently,the play in the shaft is 10mm all directions,it's proper knackered!

This is the way waterpumps usually go,strangely,a few weeks back the pump in the cabbie siezed solid....only option was to abandon the car and wife,hitch a lift home for the touring and a tow rope!
Cost me a LOAD of brownie points.....

[simonsimoff]

I use a 10mm spanner on a pulley bolt positioned where it can't turn and where it prevents the pulleys from turning. Then the 32mm (also same size as a bike headset spanner) can take the fan off really easily with a bar on it - reverse thread as mentioned.

They say storing the fan upright supposedly prevents its bearing lubricant from seeping out.

[Jesus325iTouring]

Bet you were popular Malc

Simon,thanks for the illustration,the mentally sub normal members such as myself need to see pictures to understand things Again, a great help,thank you.

[Sanchez]

If the fan bolt is stubburn put a wooden block on the chassis leg and turn the engine with the key briefly, with a long C spanner the spanner will hit hte wood and release the bolt. (remove rad 1st)

or

Remove the thermo-fan (left-hand/reversed thread) by clamping it with a vice grips and giving it a sharp blow clockwise.

[Barx325i]

well I'm going to put my 5pence worth in.

for the fan I use a heavy adjustable, the one I have just slim enough to get between the gap. I put a big rag in its way, and give the adjustable a good sharp smack with a hammer

Works every time, & it's off in seconds. My one question is if it's advisable for the coupling?

[Jesus325iTouring]

I'm loving all the suggestions as to how to undo the coupling,it's interesting to see all the differnt methods.

[town325i]

To make it easier to get off in the future grease the thread makes life so much easier. I have a big set of stihlsons that i put around the water pump pully then i give my 32mm spanner a little tap depending how long the fan has been there decides how hard to hit

im surprised no one has said the cheisel method yet

[JWaller360]

I'm glad the iS has more room to play with, the M20 looks like a tiny gap to get a spanner in!

I had to use plumbing grips on mine (the square adjustable type that tightens as you turn) which would definately not have fitted in that gap above! annoyingly, my largest adjustable spanner stops at 30mm...

[psychochild187]

you can do water pump without doing the cambelt.
the tensioner doesnt move.
and the 32mm spanner with the alternator belt tight and a hammer . towards the passenger side so clockwise.

[Jesus325iTouring]

Well,job done

I was unable to undo the viscous fan in place as it was so shagged,so I just took the water pump and fan out in one go,put it on the floor and undo it with no drama using mole grips,wasn't particularly tight.

I feel ashamed though.

I had already ordered the part yesterday for next day delivery so was too late after reading about cambelt change to order one for today,so I didn't bother to change it. Also,I found in fact I didn't need to remove the belt or anything to with draw the pump,it slipped out of place just fine. Cleaned up the face,refitted it all.

All seems ok now

Thanks for all the advice,it was a great help

My one addition to this advice and job,given all the work takes place at the front of the engine,remove the bonnet,my goodness,how much easier it was to work. It took 5 mins to remove and about 10 mins to refit,def worth the extra job to make life easier,no twisting about,plenty of light,and much easier being able to stick arms in where needed and being able to see everything clearly.

[Jesus325iTouring]

Oh and the water pump was absolutley wrecked!

[Ziggy]

Good stuff. I did the one on my E36 last weekend... & I'm struggling to remember the last time I had a car that didn't need a waterpump during my ownership!

[Jesus325iTouring]

To right,much easier.

Jon,it's the first pump I've had to change on any of the turds I've owned,my most common item is ball joints,but then driving along tracks doesn't help on my jaunts across Salisbury Plains!

[Ziggy]

They just don't like me I guess...

Still, not that bad a job. & the E36 one didn't even leak - very considerate of it. I think the worst was on a ford cologne lump - emptied the coolant at a ridiculous rate!

[Jesus325iTouring]

Mine didn't leak at all,I'm quite suprised TBH given the movement in the shaft,the old pump had some serious corrosion on it too,doesn't say much for the rest of my cooling system

[mrLEE30]

it was probably empty of water Rog!

i was always told if my M20 did not leak water or oil then it was probably time to fill them!

[Jesus325iTouring]

it was probably empty of water Rog!

i was always told if my M20 did not leak water or oil then it was probably time to fill them!

PMSL......yeah,yer proberly right

[E30_Crazy]

On the subject of Fords.... I had an Aerostar that lost it's water pump. After being filled, the coolant was gone in about 2-3 miles.

[gooner1]

On a side note to this, the torque sticky states 40nm for the the large nut,
however when i try to tighten it much more than finger tight the whole pulley /belt assembly turns. Is that tight enough

[Brianmoooore]

IMHO, yes. Just give the 32mm spanner a tap with the hammer.
Never had one come loose yet.

[daimlerman]

On a side note to this, the torque sticky states 40nm for the the large nut,
however when i try to tighten it much more than finger tight the whole pulley /belt assembly turns. Is that tight enough

As the coupling has a reverse thread,the very action of the belt turning the pulley will tighten it in use,that's why the bloody things can be so difficult to remove!

[town325i]

On a side note to this, the torque sticky states 40nm for the the large nut,
however when i try to tighten it much more than finger tight the whole pulley /belt assembly turns. Is that tight enough

As the coupling has a reverse thread,the very action of the belt turning the pulley will tighten it in use,that's why the bloody things can be so difficult to remove!

The ones i fit are easy to get off i fill the thread with grease to make removal when it does break easy to do

[Jesus325iTouring]

All is good with the new pump etc,but I have noticed my viscous fan appears to be "on" all the time,whilst I don't particularly object to the engine being kept cooler constantly,the fan noise can be annoying.

What could I have done wrong? As far as I'm a aware the fan can't be locked in position to be on all the time.

I took notice of what was said regarding keeping the fan upright when it wasn't on the car so don't think I could have upset the fluid.

[town325i]

The fans can seize up so they are stuck on