Been a bit smug, having gone through two service periods now (over 12k!) without any problems (is this a record?)- worse still, not even been logging onto the site!
My P38 diesel 2.5 (year 2000 with 130k miles), always shows the needle at around 1/4 of the scale on temperature gauge. Now it reads at the 12 o'clock position and engine noted to be running hot. Thermostat is a must replacement and I notice (from excellent earlier posts) that the viscous fan is also suspect as it does not spin freely when engine is cold and seems to come on immediately when engine is started from cold. The radiator is only two years old. I'm getting the "book" illustration (sporadically) on my info centre, next to temperature (with or without air con in play).
Main point is, need to tow caravan (1900kg) for a week's outing on Sunday. Got the thermo from main steelers, but wondered who'd be best for next day delivery on viscous fan assembly. Also any wisdom out there on getting that bleedin' fan out. I'll need one o' them spanners too. I appreciate there's a L/H thread here, but would appreciate also any wisdom out there. The manuals I have (RAV and hardback copy of official workshop) refer to two spanners. Will a hard knock to the right with one appropriate spanner really do the trick? It all looks pretty tight in there and the manuals are pretty short on detail about removing that fan cowl, that completely encircles the fan.

Maybe nowt wrong with the viscous, they are always a bit stiff when cold until they get some load on. The test is with the engine hot, take a rolled up newpaper and stick it in the blades with the engine running (mind your hands), if the fan stops it's shot, if it chops your newspaper up it's OK. Test youir new stat in boiling water on the stove to make sure it opens fully, there have been a few that don't. You can easily wire your aircon fans to provide extra cooling.

Sounds like it working correctly if it's at 12 o'clock, 1/4 isn't.

Getting fan off can seem impossible, it needs and almighty whack with the water pump pulley held, i rigged up a flat bar with two holes bolted to the pulley bolt holes. I thought i hit it so hard i must have damaged the water pump, so much so i bought a new pump in case i needed to replace it.

Viscous fans are difficult to prove one way or the other. When cold they spin up then are supposed to lose their drive until they heat up with heat from the engine and drive in earnest. Even with mine off and on the bench I still wasn't convinced and bought an original replacement. My thinking was that the money spent here might save me a head later.

If you're having the fan out and doing the stat then you might as well do the pump whilst you're in there. The original BMW one had a plastic impellor and these have been known to break up. Metal replacements are available.

On mine the rad cowl was a one piece item (not the two piece as shown on Rave) and I had to lift the rad out to get it off. This wasn't too bad as I already had the aircon condensor out and I took the chance to flush the rad through and check the baffle. If you find that you have a one piece cowl you might want to think of making it into a two piece with a sharp implement if you run into trouble. I've never re-fitted my cowl as I wanted easy access in case I had further problems and whilst I've not had any issues it's still in the garage. However I don't tow with the Rangie.

You can loosen the fan coupling with a big screwdriver and a hammer. Use the screwdriver like a chisel and have the blade just behind one of the flats on the fan nut a couple of good belts with a heavy hammer WILL loosen the fan, then just spin it off. Make sure when you spin it off that it doesn't fall into the radiator. If the shroud is one piece then you can lift the fan and the shroud out together. To check the fan coupling, switch off the engine when it is hot whilst looking at the fan. If the fan carries on spinning freely for several seconds (5-10 seconds or more) then it is worn. Also check for movement in the fan bearing, get hold of the fan (engine switched off)and try and wiggle it backwards and forwards, there should be little or no movement.

Thanks to all for responses and ideas, very informative and much appreciated.

I've now determined that the viscous fan has had it, so will be replaced too, together with the water pump while I'm at it.

Regards

Doug