I have a 2011 Nissan X-Trail, 2.0 Turbo Diesel.
Couple of days ago, we had a heat wave 39C / 102F. Normally the temp gauge gets close to the vertical axis of the cluster, so not really in vertical position.
While driving in slow traffic, AC turned on, I notice the gauge approaching the vertical axis, then slowly getting back to it's old position. And then slowly fluctuating towards vertical and it's regular position.
Car ran fine, but it cought my attention, because this never happened before.
A couple of hours later, still 39C / 102F, car has been sitting in the parking lot for 4 hours. I hooked a cheap OBDII reader and monitored the coolant temp from my phone.
While driving constantly with speeds between 60 - 80kph (40 - 50mph) the temperature in my OBD scanner rose to 103C / 217F. At that time i stopped the AC, which redused the temp to 99C / 210F. The whole time, the dash gauge sat still, a couple of degrees close to the vertical axis.
The radiator fans seem to work fine, both turn on.
The problem seems to get worse with AC on.
Temp increases if I go over 2000rpm.
No warning lights or error codes, car runs ok, no loss of power.
Coolant level always steady (in both overflow tank and radiator), no loss, in 2 months since i've had the car. There is an electric turbo cooler pump, which draws coolant, after stopping the engine. But the coolant returns to the overflow tank after the pump runs for a couple of minutes. This pump only runs with the engine off.
Also, I noticed, that the engine hood and front wings of the car get hot after driving, almost to the point of burning your hand.
What should I do, to check if indeed there's a possible overheating issue?
Should I trust the OBD scanner temp or the dash gauge?