CJCB Coolant

[Mr04vea]

Hi.

Coolant temp is not getting to 90c with the heaters on. With the heaters off, I can get 90c.

I have replaced both the main thermostat housing and the inline thermostat with genuine parts from TPS. There has been no difference whatsoever. 

I have also tested the sensor using VCDS and after a 30 min journey the temp is sat at 74c at the sensor and 56c at the radiator. 

 

Can anybody suggest what else I can try please? Fuel economy has dropped and I fear a lack of heat may interrupt the regen process.

 

Car is a 2014 2.0 TDIe. 136bhp. 117k. CJCB.

 

Thank you. 

[Stevey Y]

2 hours ago, Mr04vea said:

Hi.

Coolant temp is not getting to 90c with the heaters on. With the heaters off, I can get 90c.

I have replaced both the main thermostat housing and the inline thermostat with genuine parts from TPS. There has been no difference whatsoever. 

I have also tested the sensor using VCDS and after a 30 min journey the temp is sat at 74c at the sensor and 56c at the radiator. 

 

Can anybody suggest what else I can try please? Fuel economy has dropped and I fear a lack of heat may interrupt the regen process.

 

Car is a 2014 2.0 TDIe. 136bhp. 117k. CJCB.

 

Thank you. 

Hi it sounds more like the cylinder head temp sensor as that would give poor fuel economy, if the new thermostat is the type with a sensor in it that would have been new.

Steve.

[Mr04vea]

40 minutes ago, Stevey Y said:

Hi it sounds more like the cylinder head temp sensor as that would give poor fuel economy, if the new thermostat is the type with a sensor in it that would have been new.

Steve.

Hi Steve.

 

 

 

I've not heard of a cylinder head temp sensor before. I assume this is different from the sensor I'm testing on the VCDS screenshot? The new thermostat and housing didn't have a sensor on it. Can you elaborate more on this sensor and I'll have a look on VCDS. 

 

Thanks.

[Stevey Y]

23 hours ago, Mr04vea said:

Hi Steve.

 

 

 

I've not heard of a cylinder head temp sensor before. I assume this is different from the sensor I'm testing on the VCDS screenshot? The new thermostat and housing didn't have a sensor on it. Can you elaborate more on this sensor and I'll have a look on VCDS. 

 

Thanks.

Hi, if the ECT is not on the thermostat housing it will be nearby the thermostat somewhere I am not familiar with that particular engine but the principles are the same, yes that is the right coolant sensor you are reading on VCDS and the clue lies in the sensor reading VS the realtime radiator temp reading the sensor reads higher but not high enough so the PCM thinks the engine is cold all the time and will step up the fueling to try and warm up but if the coolant sensor will only go as far as 74c the engine will think its cold all the time, they work on the principle of the temp of the water gets higher the resistance in the sensor will lower itself until it reaches the prescribed temp, also some of the engines are fitted with dual thermostats, if you pm me your vin I will look on my parts system.

Steve.