coolant temp sensor/gauge problem

[JonXp]

Hello! Having a real hard time with the coolant system on the 520i m50. My car recently started showing strange temperatures when driving on the motorway so I decided to give her a coolant change and change the sensor at the same time. Now.. new coolant is in the system and bled. The gauge now however is showing 0 and showing no signs of life... I'm not sure if I have the wrong sensor... The one I had taken out was brown/orange in colour and had just one pin. The new one is black with 2 pins does anybody know if this is correct, gsf are positive its the correct part.

[Tiger]

it should be identical sensor... just swap the old one back in. You won't lose much coolant during this quick change.... make sure it is depressurized and keep the radiator cap on tight.

[whiskychaser]

Put your VIN in realoem or BMWfans. I put in 520i but with same build month and year as mine. It comes up with single pole sender unit part no. 12621710512. (part 6 here - part 8 is the temp sensor for the ECU)
Cylinder Head Attached Parts BMW 5' E34, 520i (M50) (http://bmwfans.info/parts/catalog/E34/Sedan/Europe/520i-M50/RHD/M/1992/february/browse/engine/cylinder_head_attached_parts-2/)
GSF may well be wrong.

[JonXp]

Ahh, I may use the old one for now, although I'm on holiday soon so it would probably be best to just wait for another one to be posted... whiskeychaser! This looks much more promising though, I've looked up the part number given on that site and its come up much more specifically with the 1 pin brown/tan sender unit. Cheers man! cheers now to try and order one of these bad boys

[whiskychaser]

Ahh, I may use the old one for now, although I'm on holiday soon so it would probably be best to just wait for another one to be posted... whiskeychaser! This looks much more promising though, I've looked up the part number given on that site and its come up much more specifically with the 1 pin brown/tan sender unit. Cheers man! cheers now to try and order one of these bad boys
I know it comes up with 1 pin - 1 pin is the same as 1 pole :-) Just put your own VIN in and it should give you the exact part number and confirm how many pins. GSF/ECP should have it. Dealer prices are not as crazy as you may think and a lot of forums have dealers as sponsors. So you get dealer parts a little cheaper.

Edit: I would like to make it know that I used the word crazy and didnt put in some bouncy ball thing :-)

[genphreak]

Early M50 had single pin ones. The engine one (blue) is what counts for correct operation, the single pinner is used IIRC on all early M50B20 and M50B25 engines in e34 and e36 that ran with the Siemens (alloy) MAF so its easy to see which one it should be. The online ETKs are not reliable, but try your best and yes, go by VIN number and try going by early models in the same or other geographic markets if you can't find the right sensor listed.