Does anyone know what the thread pitch is for a s4 water temp sender,the sensor right below oil filter and next to oil pressure sensor.i tried searching but no luck,only found some info on the s5 unit but not s4..

 

Early S4s are M8x0.75, late S4 is 1/8 NPT
Does yours have a crush washer? If it does, it's metric as shown here: 86-92 Engine Electrical

S5 and later use 1/8 NPT with a 1/4" quick disconnect connector.

 

Yes it has a crush washer.
Thanks for the info.
So it's M8x0.75