While working on a 2001 VW Jetta with a 2.0 L engine, we encountered a common problem among VW vehicles, in this particular vehicle, the coolant temperature gauge was malfunctioning, sometimes it would work ok, and sometimes it wouldn't work at all.

We connected the scanner to the vehicle, and we noticed that every time the gauge didn't work, the coolant temperature readings would be wrong, based on this information, we knew that the reason why the coolant temperature gauge wasn't working on this VW Jetta was due to a faulty coolant temperature sensor.

 We explained in our previous page coolant temperature sensor, how to test a coolant temp sensor with an ohmmeeter.

In this particular vehicle, we didn't feel the need to test the sensor because the readings on the temperature gauge in the dashboard and the readings in the scanner were similar.

Take note that even though the vehicle we are working on is a 2001 VW Jetta, the steps described in this page will apply to 1993-2005 VW Jetta, Golf, GTI with a 2.0 L engine.


NOTE: Before you start working on the vehicle, make sure that the engine has cooled down, or better yet, do it in the morning before you start the engine, if the engine is cold, it is not necesary to drain the engine coolant to perform this job, but you can choose to drain it if you want to avoid spilling engine coolant on the ground.

     

  

   

   



   

  

 

    

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  If you don't know the exact coolant temperature sensor  location on your VW Jetta, Golf or GTI with a 2.0 L engine, follow the upper radiator hose, the coolant temperature sensor is mounted to the water outlet located on the rear side of the cylinder head by the transaxle.

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To show you how to dissconnect the electrical connector from the coolant temperature sensor, we unplugged it for easier view, insert a short flat screwdriver as shown in the picture, pry gently by tilting the screwdriver sideways and pull the connector away from the sensor.

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This is the close view of the coolant temperature sensor electrical connector still attached to the sensor.

 

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Next, using the same flat screwdriver, pry gently on the retaining clip that holds the coolant temperature in place, be careful with this clip, it is made from plastic. 

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This is what the coolant temperature sensor retaining clip looks like, if you are reading this page and you haven't started this repair, it is recommended to buy a new retaining clip before you start working on the vehicle, that way if you break the clip while taking it off, you have a new one to replace it with. 















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Next, pull gently on the coolant temperature sensor and remove it from the vehicle.











Apply a thin coat of petroleum jelly to the seal of the new coolant temperature sensor, that way it will slide in place easier, next install the retaining clip, plug the electrical connector in place, add coolant if you either drained the coolant earlier, or to replace any coolant you may have lost when you removed the coolant temp sensor from the vehicle.








Start the engine and watch the gauge, depending on the coolant you drained from the vehicle, there could be the possibility of air pocket in the cooling system, air trapped in the system will cause the thermostat to malfunction, causing the engine to overheat, if you see the coolant temp gauge rising above 210 degrees, stop the engine, allow it to cool down, ad the necesary coolant and re-start the engine again, repeat the process untill the coolant temperature gauge remains in normal working temperature. ( 195 degrees )