Coolant temperature readout obd2.

[Chessbo]

Hello everyone.
Does anyone know what temperature sensor the OBD2scan is reading from correctly?
I am driving a 2017 T6 110kw.

I noticed a few months ago that my gauge of my coolant was very slow to warm up and in some cases did not even reach 90.
My mechanic told me my thermostat was probably broken.
After a repair of almost 2k further with a replacement of the electronic thermostat, water pump, distribution and so on, I notice that there is definite improvement but it is still more sluggish to warm up than it was before the problems. If I don't do highways it takes almost half an hour until the gauge gets really to 90. On trips through the village the gauge does not touch 90.

When I read the coolant temperature with an OBD2 scanner it comes up that the coolanttemp is only 72 degrees. Even though the gauge is at 90. is this normal? My mechanic says there are multiple sensors in different places in the engine which can cause the temperature to vary.

Many many thanks ,
Chess

 

[n10n]

When I read the coolant temperature with an OBD2 scanner it comes up that the coolanttemp is only 72 degrees. Even though the gauge is at 90. is this normal? My mechanic says there are multiple sensors in different places in the engine which can cause the temperature to vary.

The difference between OBD readout and the gauge is normal. The gauge is weighted to hover at 90 from about 75C onwards, I suppose to ease drivers from not panicing over slight water temperature changes.

Here's how the water temperature looks like in <10C outdoors temperature in mine (blue curve), the actual 90C water temperature is reached at about 20 minutes of driving but gauge will show 90C already before 15 minute mark. This was countryside driving, varying but about 80km/h.

 

[Chessbo]

The difference between OBD readout and the gauge is normal. The gauge is weighted to hover at 90 from about 75C onwards, I suppose to ease drivers from not panicing over slight water temperature changes.

Here's how the water temperature looks like in <10C outdoors temperature in mine (blue curve), the actual 90C water temperature is reached at about 20 minutes of driving but gauge will show 90C already before 15 minute mark. This was countryside driving, varying but about 80km/h.

Thank you for your input! Interesting to see.
Before the problems my gauge always reached 90 degrees after 15minutes. Also with short and slow drives. Now with a new thermostat it doesn't. Is there something else wrong or should I just give up worrying and go with the flow . 72 degrees is warm enough for the engine?

Thanks!

 

[n10n]

Thank you for your input! Interesting to see.
Before the problems my gauge always reached 90 degrees after 15minutes. Also with short and slow drives. Now with a new thermostat it doesn't. Is there something else wrong or should I just give up worrying and go with the flow . 72 degrees is warm enough for the engine?

Thanks!

Sounds like you still have some issue with warming up and 72 is definitely low, it should get up to 90. But the difference in OBD vs gauge before engine has warmed up is perfectly normal.

Thermostat is kind of the go to answer for this kind of problems, not sure what else it could be.

 

[n10n]

The coolant system in these vehicles is perhaps "slightly complicated"

This image is for 150kW CXEB so might not be exactly the same as yours but this has to be my favourite VW diagram I've encountered:



There is indeed multiple coolant temperature sensors in the engine, in all versions. That said, I believe OBD temperature and what goes to clocks should be from the main G62 sensor.

G62 - coolant sender
G83 - radiator outlet coolant temperature sender
G812 - coolant temperature sender 3

Also look at Slow to heat up to learn bit more about the system operation.

 

[DXX]

2K quid to chase an 18 degree discrepancy! Is it causing a problem?

 

[Chessbo]

2K quid to chase an 18 degree discrepancy! Is it causing a problem?

I just see when somethings off with my van, and I know one thing about cars, an engine has to be on temperature. Especially with all these EGR valves and things other recent engine addons. Had to replace the egr cooler in the past (also 2K). So with fear of big problems on the long run, I seeked for help.

 

[Chessbo]

The coolant system in these vehicles is perhaps "slightly complicated"

This image is for 150kW CXEB so might not be exactly the same as yours but this has to be my favourite VW diagram I've encountered:



There is indeed multiple coolant temperature sensors in the engine, in all versions. That said, I believe OBD temperature and what goes to clocks should be from the main G62 sensor.

G62 - coolant sender
G83 - radiator outlet coolant temperature sender
G812 - coolant temperature sender 3

Also look at Slow to heat up to learn bit more about the system operation.

Awseome, thanks man.