- normal driving (mixed urban and national roads, not pushing much for the engine): takes around 10 minutes to reach 70ºC, then slowly progresses to about 72ºC on a cool morning or 75, maybe 77ºC on a hot day. If A/C is OFF (no fan), it might eventually reach 80ºC after some more time. But with A/C, it only reaches 80ºC on a really hot day.
- city traffic: on a warm day it might reach 90ºC, but normally only if A/C is OFF. Seems the slow mode fan is enough to avoid it reaching 90. This is a nice touch, makes this a safe engine regarding over heating risk under these driving conditions.
- motorway driving at 110-120km/h: stays at 72ºC, sometimes 75ºC, not more, because of the wind, or because of the fan if A/C is on. On a hot day, goes to 80ºC and stays there.
- motorway pushing it a bit at around 130-140 km/h on a hot day: goes easily to 95ºC even with A/C on, or 100ºC with A/C off, I think I've seen it reach close to 105ºC once (and MAYBE heard the fan switch on in fast mode, but wasn't sure). Both fan work fine, the other day I had it idling a bit longer as I was waiting for someone, with A/C on, and it was very hot weather, and temp rose and then fan went to fast mode and cooled it enough.
So, I'm asking if anyone who had (or has) a XUD11 (or even a XUD9, although it has different cooling system, it's the about the same engine design), if these temperatures seem normal or seem to indicate that thermostat might be stuck open or not closing totally. I've noticed that there are thermostats with different opening temperatures for this engine (80 and 82ºC, but no 75 or lower).
I don't think the temp gauge is showing a lower than real value, btw, because it's stable and if A/C is off, the fan doesn't come on before something like 95/97ºC, if it was showing low temp, this would already be temperature for high speed fan, no? Don't have IR temp meter to check this, though.
Ah, heater inside works fine, btw.
Thanks for hints and opinions. Not that this is really worrying me, as the car drives well, has good mpg (has been doing around 6,7 lts/100 km), just have been noticing that on a cold morning, it drives less well when at 72ºC, compared to when at 80ºC on a warm day... it's a small difference, but can be felt. So I wonder if this is not the best operating temp and caused by thermostat open or not closing fully, or if it's simply the XUD which runs really cold and with cold weather (or A/C fan) is unable to gain more heat unless being pushed.
I know the thermostat is a cheap part, but I also learned that unlike the XUD9, in the XUD11 the thermostat is a real "PITA" to change
, you have to jack up the car and apparently it's still a nightmare to access. So I don't want the mechanic to do this, as it would be expensive, but I also don't want to take on such a hard task by myself unless it's really quite sure that the thermostat is not working correctly.Therefore, some more tips on how to correctly do the "hose feeling" test would be great. If all this ends up inconclusive, I might simply wait for colder weather in a few months and then see how it behaves, I think then it should be more clear.
. But first I really have to repeat the hose feel test and be more certain that it needs replacing.