Hi all - I have a 2013 A7 w/ the 3.0t supercharged v6, about 59,500 miles. Recently, my temperature gauge deviated a bit and ticked up a notch from the center line, and all the fans kicked on. I panicked a little bit and brought it to a dealer's service bay (my only option where I'm located), and long story short they told me "sometimes they just do this, don't worry about it unless it keeps happening." They explained that it shouldn't really happen all that often, but if it does once in a while, it's okay. They also told me I have an oil leak coming from above my timing chain covers. After being quoted 4500$ to fix the oil leak, I ended out leaving with my car, being told it was "perfectly safe to drive" and that "as long as you keep adding oil, theoretically you can keep driving forever." This was on saturday 10/4. Since then, the car has continued to have temp increases - I got on the highway and the gauge showed all the way up to the notch below overheating, and that was less than 30 seconds after I hit my 75mph cruising speed. It's regularly sitting 1 or 2 notches above that center mark. The only way to keep the engine heat down is to put on the cabin heat, which is obviously uncomfortable after a little while. I did notice today that when I left the car idling for 2-3 minutes with the heat blasting (I went into a gas station) the gauge showed one below the center line as well. I should note that I've never had any issues before, the temp gauge has stayed consistently on that center notch and hasn't traveled above or below that line, ever until now. A couple of things to note: coolant is visible in the reservoir, car has had regular oil changes/service, no history of problems. I don't know about any coolant flushes or if the spark plugs have been done yet.

All of this comes with the dealership also telling me there was nothing wrong with any part in my cooling system, checking my water pump, thermostat, and running multiple different diagnostic tests, as well as using a borescope to attempt to diagnose the issue. They're taking it back thursday to check it out again, but in the meantime I've just been driving carefully and using my heat. My question is, is something wrong or am I overthinking/overreacting to this? I've never seen the gauge fluctuate before and I can't seem to find anything online that pertains to this specific situation.
Thanks so much to anyone who can provide any input!

 

Not overreacting at all, once warm that gauge should never move, hot or cold weather. I have the same car and often watched the temp readings on my phone, on the hottest days, under the harshest conditions it will climb some 20F-25F the most, with no change on the factory gauge. It's interesting that turning on the heater alleviates the problem, I wonder if there is an air pocket that is working its way up through the additional channels, or if the trick just works to alleviate the overall heat. This engine also has an auxiliary electronic water pump, but I think that only kicks in when the car is off. Let us know what they come back with, something is definitely not right, best of luck.

 

Thermostat needs replaced., good idea to change the water pump in the process as well.

It will not be cheap.