hi

anyone help whith the location of the engine coolant temperatur sensor on an octavia

1.9 tdi. is it on the radiator

The one for the temp gauge is at the back of the engine towards the gearbox. They are a common fault if the temp gauge is jumping up and down. Not easy to see, but dead easy to change - 30 second job

i have a fault code 17664 whitch says engine coolant sensor would this be the one

Pretty sure yes, its the only one in the engine to my knowledge, when mine went i just changed it without a diagnostic check.

Simply unplug the sensor, pull the clip off, then with a stone cold engine pull the old one out (make sure the seal comes out with it) and pop the new one back in, you will loose about a cupful of coolant - a little more if the seal isn't on the old sensor.

On my 110 tdi the temp sensor is on the right of the block ( looking from the front ). Disconnecting the sensor connecter will cause the dashboard gauge to read 0 and the glow plug light (and plugs) to remain on. havn't had to change it yet.

got it sorted lads thanks for the help