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Discussion Starter #1
OK so today I have made my way back from Manchester to London and as I came through the roadworks on the M1 the temperature gauge started indicating that the engine was trying to be the Sunday Roast :) So I pulled over, checked and found it was still full of coolant, as I came off the motorway the temperature dropped to 90 almost immediately. So thought I'd try and get home, turned the heaters up and set off. Got back the last 30 miles and bar one instance of it getting warmer again it made it.

So googled it on here, checked everything I can so far and just looking for a more definitive answer. The top hose could do with being replaced as it's looking rather tired (not a problem and will sort it). The car does have A/C so has the dual electric fan rather than full engine driven viscous fan. The car had a new radiator fitted shortly before I got it. It has been faultless for the last month since I bought it. When I got it back I left it idling for a while to see if the fan kicked in and it didn't. Googled and found a post on here about shorting out the fan to test it and rule out the fan or temp sender. So it would appear that the High Speed Fan works when shorted out (and when the A/C is on) however there is no sign of the low speed fan working when shorted out (pins 1 & 2 from memory). The relays are in the fuse box and I assume they are working (so far). Thought I would just give replacing the fan coupling a go but then when I realised it wasn't exactly cheap thought I'd check on here first.

So my question is, it it likely to be the fan coupling that means the low speed does not work but the high speed does?
 

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Discussion Starter #4
I will give it a go although I did swap the two yellow relays around yesterday which I believe are for the A/C and low speed fan. Are these a BMW supply or will Halfrauds sell them?

When activating the high speed fan, it doesn't sound rattly and horrible as it would if the bearings had gone so I am understandably reluctant to spend £40 when it might not fix it
 

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Discussion Starter #6
Thank you very much for that. I have been reading through them, will give it a go with both relays and see how I get on. I have just been to the local BMW dealer and they didn't have them in stock but as I can't get back to them this afternoon will try and order one near to work.

The pins don't look particularly burnt out but after seeing the insides am half tempted to take it apart and check anyway :) nothing to loose lol.
 

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not sure on your problem but abit info and advise if you dont kn ow this but keep your heaters on full whack on hot as it lowers the engine temp alot. by a quater on mine . it gets hot but just open the window and turn the blower down a tad once engines cooled.
would save it overheating and damaging anything
 

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Discussion Starter #9
Thanks Drewlad, that is what I have been doing. Had another look in some better light and can see scortch marks on the yellow relay so suspect that its at fault. Will get one ordered at the dealer and see how that goes.

Gildersol, will go and check fuse F16 shortly and see what it's like. Not checked any fuses in particular as the fusebox cover indicates that it is well hidden under the dash :)
 

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Discussion Starter #10
Just a bit of an update,

Glidersol - The fuse F16 is in tact :)

Ordered the relay at BMW near work, set off this morning and got over half of the way there and it started overheating, immediately wacked fans to full but it didn't start bringing the temp down, pulled over and stopped just as the red light came on, checked under the bonnet and the coolant had boiled over and spat out. AA man dragged me off the M1 to Watford Gap Services where it looks like the Water Pump has died a death. Luckily I was paranoid already and was monitoring the temperature and it looks like I saved the head gasket as the sniff test came back clear and a pressure test shows no pressure change in the water.

So the overheating issue was down to the water pump giving a warning however it did highlight the broken relay thank you very much.
 

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Discussion Starter #11
OK So I have replaced the relay and still no fan on low speed. If I short pins 1 & 3 I think it is I get fan, short 1 & 2 and nothing. Going to finish rebuilding the cooling system this afternoon and see if I can do some more digging
 
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