Hi gang,

Using the stock K1100 coolant temp sensor in my K100´s water pump....Am I able to use any aftermarket temp gauge or will only the BMW one work?

I have a BMW one here but its really old and the sight glass is cloudy and yellow. It does not appear that the unit can be dismantled.

I am by no means an expert, but I recently installed a BMW K1100 temperature gauge on my 75RT.  It would not work with a VDO sender as the resistance curves are different.  As a result I had to use the grossly overpriced BMW sender. 

I suspect an aftermarket gauge will not work and you will need to use an aftermarket sender.  Not a big deal, because you can remove the old harness from the BMW gauge and you can buy an aftermarket gauge and sender for less than the price of the BMW sender let alone a gauge.  Both gauges should have the same basic connections (ie. +12v, ground, temperature signal, and night lamp) coming in through the harness.

Excellent, thanks.

Can anyone tell me what size thread the sender has? Do the sender units tend to be of a standard size?

THIS looks alright, but im not sure about that sender. From memory the stock one does not protrude into the pump that much?

floyd wrote: Can anyone tell me what size thread the sender has?

M10 x 1,0.

floyd wrote: From memory the stock one does not protrude into the pump that much?

I tried this one.  It fit ok, but didn't work with the BMW gauge.  Should work with the VDO gauge.

http://www.ebay.com/itm/VW-AUDI-VDO-TEMPERATURE-SENSOR-SENDER-PART-049919501A-WATER-OIL-0-125oC-257oF-/141053356326?pt=Boat_Parts_Accessories_Gear&hash=item20d76f6926

I think I remember seeing motorworks advertising used senders (IN USEABLE CONDITION ) ...for quite cheep money Floyd

my experiences with different meters  leaves me to comment that not all meters expect the bmw sensor ..."auto meter" can be made to show close to accurate with external additional resistance

but the bmw meter is expanded scale across the working range ...and is a very good design feature


opps addition

perhaps otto instruments could replace the sight glass ..those guys have specialised tools and the knowledge and patience .....ask first  cause I don't know his prices ,,,, just a thought as I recon it could be a better secondary  (cheaper) option to also get a bmw guage off secondhand from motorworks

good luck mate