1.9TDI ASZ Temperature sensor location

[dawie102]

Hi All,

I have a 1.9TDI ASZ and lately when driving I see the temperature takes ages to move. Only when on the high way ~5km drive from my house the needle starts to rise to 50 degree and 10min later to 70 degree. During the drive the temp will go down to 50 degrees and sometimes to zero degrees. I have seen this issue on my 05 polo 1.6i and replaced the temp sensor and all was resolved.

My question is where is the temp sensor located as on the ASZ engine as I was trying to trace the cooling lines but could not fine the sensor. Can someone please provide a picture or diagram of the location for this sensor. Can you guys advise if it is the grey plug (2wire) or green plug (4wire).

Thanks in advance.

Kind Regards
Dawie

[THANAS]

More than likely a thermostat and not a temp sensor issue.

Sent from my CLT-L29 using Tapatalk

[VGTI]

It is the grey sensor...

Just under the tandem pump at the back right of the engine. Remove pipe between airbox and Turbo Inlet, maybe even airbox.

Quite easy to do but don't expect to do it without losing half the coolant. Just do a flush and maybe the thermostat at the same time. Thermostat is cheap enough and while the coolant is out easy to do.

https://www.youtube.com/watch?v=PE82KM-ikt0

[dawie102]

Hi VGTI,
Thanks for the video, do you think the symptoms I have is definitely temp sensor causing this behavior on the TDI?

[VGTI]

Hi VGTI,
Thanks for the video, do you think the symptoms I have is definitely temp sensor causing this behavior on the TDI?

The temp sensor issue gave me an engine (emissions) light on the dash board, so scan with vag com and check for errors.

If it warms up on long runs and downhill drop below 90 then thermostat. But like I said if you replace the one you might as well do both as the coolant will be on the floor

[Jueshen]

whenever this happened to me on my 1.8T or TDI was always a stuck open thermostat

[dawie102]

Hi All,

I Have replaced both thermo sensor and thermostat and seems problem is resolved. I also noticed a lot of rust/corrosion built up inside of the pipes and thermostat so I cleaned out all the pipes and flushed the cooling system.

[Jueshen]

Nice, well done! Latest always flush coolant every cambelt service.

Enjoy the temp Needle staying put!