Normal coolant temperature for a 2019 132TSI B8?

[Cruzym8]

Hi everyone,


I recently bought a 2019 132TSI B8 Passat (wagon, 7sp DSG) and took it for a service last week.


Before the service I swore I heard a strange noise from under the bonnet, so I plugged in a generic scan tool and it threw the P00B7 code which is for 'low coolant flow/performance'.


I kept the live dashboard on as I drove around and the coolant temperature reached 109 degrees Celsius. It seems to drop back down to around 98c after being at that higher end for 10-20 seconds but it always climbs back up. It seems to oscillate like that.


I informed the VW dealer who I'm getting it serviced with due to warranty, and he said that the mechanics found no code and that 109c is not a concern.
They did a pressure test on the cooling system and found it to be holding pressure fine.


Is this temperature too hot?
All other cars I've owned seem to sit around 96c and are pretty stable at that temp for long periods.


Cheers.

[Guest001]

Thermostat faulty or water pump on way out My Passat used to sit on 90

[Cruzym8]

Thermostat faulty or water pump on way out My Passat used to sit on 90

Thanks for your reply.
VW mechanics said they couldn't fault the thermostat or water pump (I think it's a combo unit in these models?).
Is this just a flat out lie so they don't have to pay to replace it on warranty then?

And which Passat did you have that sat at 90?
Appreciate your time,
Cheers.

[Lucas_R]

Coolant temperature does fluctuate, despite the standard temperature guage constantly showing 90c on the dash. But 109c is probably a bit high.

Assuming your waterpump/thermostat is not leaking (very common issue - expect to replace every 4 yrs or so) or faulty, then you may have a faulty coolant temperature sensor somewhere (there are multiple on the engine) or a damaged plug/wiring.

[Guest001]

Thanks for your reply.
VW mechanics said they couldn't fault the thermostat or water pump (I think it's a combo unit in these models?).
Is this just a flat out lie so they don't have to pay to replace it on warranty then?

And which Passat did you have that sat at 90?
Appreciate your time,
Cheers.

128TDI and it did increase slightly on a long hill which is normal but dont remember it getting up near yours

[Cruzym8]

Thanks both, much appreciated.
I'll do a bit of digging - glad to hear I'm not going mad over the 'high' temps.

At the very least I'll get a second opinion.
There are no leaks around the thermo/pump housing, and I'm not sure I can be bothered to test all of the sensors (if there are multiple).

Cheers.

[petemac110]

Thermostat faulty or water pump on way out My Passat used to sit on 90

The temperature displayed on the dash is highly 'sanitised' to stop people freaking out. You'd be amazed how much the temperature actually fluctuates whilst the dash happily displays 90 degrees. It takes quite a high coolant temperature for the gauge to budge above this.

Thanks both, much appreciated.
I'll do a bit of digging - glad to hear I'm not going mad over the 'high' temps.

At the very least I'll get a second opinion.
There are no leaks around the thermo/pump housing, and I'm not sure I can be bothered to test all of the sensors (if there are multiple).

Cheers.

Sounds fine to me - very common when you view actual temperature data vs the dash readout) and those numbers are not excessively high provided that the temperatures are not constantly pegged that high. A second opinion/further investigation wouldn't hurt though.

[Guest001]

The temperature displayed on the dash is highly 'sanitised' to stop people freaking out. You'd be amazed how much the temperature actually fluctuates whilst the dash happily displays 90 degrees. It takes quite a high coolant temperature for the gauge to budge above this.
Sounds fine to me - very common when you view actual temperature data vs the dash readout) and those numbers are not excessively high provided that the temperatures are not constantly pegged that high. A second opinion/further investigation wouldn't hurt though.

Yes how true I had a TDI Cruiser and the gauge never moved Ever ever ever UNLESS the arse fell out of the radiator and ALL the water drained. I fitted a scangauge with the sensor in the top radiator hose and it gave rather different readings which were more accurate. The old red light was probably best as as long as it stayed out no one worried up to steam coming out under bonnet LOL

[Cruzym8]

Folks,
I found concrete information from Volkswagen and Audi.

Made a video to test and describe in a very basic way.

TL;DR: 86-107 is normal, engine targets 107 at low RPM/load, and ramps up cooling when RPM/load increases.

https://youtu.be/4VT05G-xkY0