Thermostat OEM Audi or OEM Honda

I work at a Honda dealership in the mechanic field, and I would recommend the OEM thermostat, unless you have a rebuilt engine.

Stop using cheap thermostats. Get an oem honda unit and it will last and work correctly.

Your temp gauge is reading low because your mechanic is not using an OEM Honda thermostat. An OEM thermostat is designed specifically for your engine and the car will warm up quickly and the temp gauge will sit at the 50 yard line in any weather.

the 80c has been running flawless. Only difference is that my coolant stays at 83-94c. It used to get as high as 100 sometimes. Also the 80c part was recommended oe part #

Been running the 80 for a month or so. It works great. Car and Temps run flawlessly. Only difference is my average warmed up Temps are 85c. Used to be 95c

The Honda thermostat opened probably 50% more than the aftermarket, so lesson learned there.

I finally got around to installing a new thermostat/o-ring/housing and coolant reservoir/cap yesterday. When removing the thermostat, I noticed that the bottom bolt was VERY loose... I had done the thermostat without housing about a year ago now, had never leaked coolant before... My best guess is that I just didn't torque it enough and it slowly loosened, but only when cold (just a guess, but would help explain why no drips when car was running on ramps) and in small enough amounts that I did not notice a puddle on the ground.

My Q5 with 75,000 miles on it developed a leak in the water pump area. Initially Audi denied there was a leak, so I took pictures and showed it to them. Then they diagnosed it with thermostat leak.

Car takes forever to warm up and seems to always be running rich, so I'm guessing either the thermostat or ECT, or both, is/are bad.

The current plastic thermostat looks a little more beefy, but is still shatty plastic. They're commonly failing at 30-55k miles in the stuck closed position, instant overheat.