Should coolant temperature ALWAYS be 90 degrees Celsius

[Odiak]

Should coolant temperature gauge needle ALWAYS reach and stay at 90 degrees celsius?

I'm asking because about 70% of time it reaces 90°C but 30% of time it's slowly moving between 60 and 90 degrees.

I haven't found any logic out of this because it's not dependent on time driven or weather temperature.

 

Car is Skoda Superb 2014 TDI 125kw.

 

[Jonnyhatesjazz70]

Good evening.

 

Once up to temperature mine always sits at 90c. Never higher or lower.

Maybe a faulty thermostat?

[Odiak]

1 hour ago, Jonnyhatesjazz70 said:

Good evening.

 

Once up to temperature mine always sits at 90c. Never higher or lower.

Maybe a faulty thermostat?

Good eveing to you too.

Thank you for your reply.

 

Yes, I was afraid that thermostat may be faulty.  Although during the last week coolant temperature has nicely raised til 90 degrees and stayed there, even with -15 outside.🤷‍♂️

[gav_is_con]

Manual or DSG. If DSG do that stat first 

[Paws4Thot]

12 hours ago, Odiak said:

Should coolant temperature gauge needle ALWAYS reach and stay at 90 degrees celsius?

Pretty much yes, as long as the actual coolant temperature stays in the range of 60C to 110C.

[AGFalco]

 

On 16/01/2024 at 16:18, Odiak said:

Should coolant temperature gauge needle ALWAYS reach and stay at 90 degrees celsius?

Yes, but it is being economical with the truth.

 

For the last week I have been looking at the engine temperature gauge in the dash.

On this car it is digital and only displays in 5 degree C steps.

At the same time I have been looking at the engine temperature via the OBD11 App on my mobile phone.

 

The dash temp goes up very quickly to about 80 C and then can drop a little.

The OBD11 reading goes up slower and then drops later but by about 30 C.

I am guessing this is when the thermostat opens .

It then rises again, sometimes reaching the same reading as the dash one.

 

Where as the dash reading hardly changes the OBD11 has much bigger changes which depend on how hard the engine is working.

 

I have also been watching the oil engine temperature.

This takes a lot longer to rise, especially during this cold spell.

This also changes depending on how hard the engine is working.

 

Spring / Autumn readings are about 10 C higher with summer ones even higher again.

This is for both the OBD11 water and oil readings.

Meanwhile the dash gauge still shows its usual 90 C. 😮

 

Thanks. AG Falco

[J.R.]

As has been described it will sit at an indicated 90°c over a very wide range of temperatures.

 

Was it a very cold day when yours was dropping? Did you have the heater in full and were driving relatively slowly?

 

On the few cold days last week my temperature gauge never got to 90°, the thermostat had opened and the heater was delivering heat but driving slowly on B roads never generated an excess of heat, it would hit 90° going up a hill but then drop again on the flat, to be sure of what I suspected I turned the heater contro; to cold air and the gauge rapidly rose to 90°; too rapid in fact but that just reflects the fiddle factor in action.

 

I tried it a few times with the same results each time, I resolved to blank the radiator and fit my winter wheels then it got warm again it was 15° here today and did not drop below 12° during the night, I dont think the winter wheels will ever get fitted (famous last words) last winter there were probably only 3 days when would have given me any benefit but as I drive according to the conditions it was not an actual benefit, just a safety reserve.

Edited 17 January by J.R.

[AGFalco]

48 minutes ago, J.R. said:

On the few cold days last week my temperature gauge never got to 90°

 

1 hour ago, AGFalco said:

The dash temp goes up very quickly to about 80 C

But not above and yes this cold week here in the UK.

 

 

1 hour ago, AGFalco said:

Spring / Autumn readings are about 10 C higher

 

50 minutes ago, J.R. said:

I resolved to blank the radiator

Just the top half for me. Before I did this the temperatures were about 10 C lower still.

 

Thanks. AG Falco

[rbhelle]

Mostly it stays on 90 degrees in the display meter. But when temperatures reaches below -16 degrees celcius, I notice that the gauge moves from 90 degree mark down to maybe 75 mark when rolling down a hill. Moves straight up again when accelerator is active. Its just the way these engines are constructed. How do I know the temp? I use OBD 11 live data to check coolant temp.

[Odiak]

Update:

I've changed engine and DSG thermostats and now coolant temperature quickly reaches 90 degrees and stays there.

[rbhelle]

On 01/04/2024 at 22:19, Odiak said:

Update:

I've changed engine and DSG thermostats and now coolant temperature quickly reaches 90 degrees and stays there.

Perfect, should do the trick to get it up to temp again. Often many replace engine thermostat, when in fact it is the dsg thermostat that i causing the problem. Much easier to test the dsg thermostat to verify. Disassemble, run cold water through nad if water just pours through it, its broken, replace. If water halts and sizzles through it, it is ok and engine thermostat is more likely the source to low coolant temps.