E36 viscous fan
Discussion
dan101smith said:
Does anyone know the size of spanner required to remove an E36 viscous fan coupling?
I know I don't have one big enough so need to order one, but forgot to check the size this morning
Halfords sell a spanner specifically for the job at about £7 ( Laser tools ) - it's got a cranked handle to get at the nut. I know I don't have one big enough so need to order one, but forgot to check the size this morning

As said, remember the thread is the opposite way to normal - so it's "lefty tighty, righty loosy"
you'll often find that spanner isn't shaped as usefully as you'd imagine, but it'll do the job.
you'll need to brace the water pump pulley with something also, there is a special tool for it, but most people use a screwdriver threaded between some of the bolt heads on the pulley (it'll slip on the belt otherwise)
if it doesn't go easy, a sharp tap with a hammer will free it
you'll need to brace the water pump pulley with something also, there is a special tool for it, but most people use a screwdriver threaded between some of the bolt heads on the pulley (it'll slip on the belt otherwise)
if it doesn't go easy, a sharp tap with a hammer will free it
I bought one of those spanners to do my E30, the next day I got my local garage to have a quick check over the car before a trackday and I mentioned I was going to to the cooling fan. They offered to remove it for me, was harder than I expected on my car, so I drove the half mile home without one. If you've got a friendly garage ask them to whip it off for you - buying the spanner is a bit unnecessary really, although cheap it's hardly a tool you'll use regularly.
Unless you wanna buy mine?
Unless you wanna buy mine?

bramley said:
buying the spanner is a bit unnecessary really, although cheap it's hardly a tool you'll use regularly.
Although, if you haven't got a 36mm socket and have the plastic oil filter holder on your 328i, the spanner is useful for undoing the big plastic nut on top every time you change your oil ( if you do change your own oil that is ) Have been wondering about that for my E34... answer so far - I don't think it makes a significant difference.
Put it this way - all the electric replacements I'd fit to ensure no overheating consume less than 300W (<1/2hp). Granted that'd be provide by the alternator, maybe incurring a 10% penalty for inefficiency in conversion, but 330W is still less than 1/2Hp...
I doubt the rotational inertia is significant compared with 20lbs+ of flywheel either, so little to be gained from that POV.
And finally, even though mine is a v8, a little hack with the OBC quickly reveals the difference between idling in neutral and idling in 'D' at a standstill to be less than 0.4l/hr. Which I also fully expect to swamp the difference a fan-delete would show.
Guess I'm keeping the viscous fan - it's dead simple, and it works!
Put it this way - all the electric replacements I'd fit to ensure no overheating consume less than 300W (<1/2hp). Granted that'd be provide by the alternator, maybe incurring a 10% penalty for inefficiency in conversion, but 330W is still less than 1/2Hp...
I doubt the rotational inertia is significant compared with 20lbs+ of flywheel either, so little to be gained from that POV.
And finally, even though mine is a v8, a little hack with the OBC quickly reveals the difference between idling in neutral and idling in 'D' at a standstill to be less than 0.4l/hr. Which I also fully expect to swamp the difference a fan-delete would show.
Guess I'm keeping the viscous fan - it's dead simple, and it works!
Edited by Huff on Thursday 4th December 22:12
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