Postby smj999smj » Wed Jan 23, 2019 12:56 pm
Thermostats don't "break-in." They either open at the specified temperature or they don't, which is 180 degrees per Nissan. Typical pressurized automotive systems don't overheat until around the range of 248-257 degrees F., depending on the pressure rating of the cap. You don't mention under what conditions you are measuring 215-228 degrees F. At idle and at temperatures in the 60-80 degree F. range, I would expect to see coolant temperatures near the rating of the thermostat if everything is working properly...high 170's to low 190's. If you are seeing 215-228 under those conditions, I'd be a little concerned and would make sure my fan clutch and electric fan are both working properly and there is no restriction of airflow through the AC condenser and radiator cores, such as bent fins, debris stuck in the fins or leaves/papers stuck between the two cores. If I was monitoring temperatures while driving under various conditions, I wouldn't be alarmed at seeing temperatures in the 215-220 range, or slightly higher, depending on ambient temp, humidity, vehicle speed and workload. As far as aftermarket thermostats, I'm not a big fan and I usually stick with genuine Nissan. Many aftermarket thermostats tend to run a bit on the cooler side, however, rather than hotter. I'm not sure who is the OE manufacturer for Nissan in the US, but I wouldn't be surprised if it is Gates, who makes the coolant hoses and serpentine tensioners for out vehicles. In Japan, Fuji and, I believe, Sumitomo make the OE stats for Nissan.