Hello Chaps.....Long time no post!
My A6 1.9tdi (110 but "Van Aarken chipped") has developed a fault that I presume is the temperature sender; It rises to 90 as it always did but then for no apparent reason it drops off to zero. I have checked oil - no sludge, connections seem tight, no obvious water loss and no other head gasket signs.....it is the blue connector 4 pin sender. Any ideas?. Is that the only water temp sensor? it looks like you just take the sliding wedge out and draw the sender out, yes?
All help greatly appreciated