Quicksilvers

Ester oil is not 100% synthetic motor oil. Using Ester oil or a full synthetic motor oil in your 370Z will have no negative effects on your engine. As long as you change your oil on or before the recommend time to change your motor oil you will be fine. I have had oil analysis done using both Ester oil and full synthetic motor oil and conditions were no different they put different additives in the Ester motor oil. Detonation or spark knock has nothing to do with you changing your oil on your 370Z. I would pick a different Nissan dealership to give your business to they have no clue about what they are talking about. The only thing that would help you by using Ester motor oil would be to reduce drivetrain noise or valve chatter. This really is only helpful in higher mileage VQ37HR engines. At low mileage if your engine is healthy you will not experience drivetrain noise or valve chatter so there really is no reason to use Ester oil at low mileage other than for the short break in period for a new VQ37HR engine. Your best choice would be to change your own motor oil and oil filter it is a easy diy and you know it will be done right if you do your own oil change. Since after my break in period was over I have been using Valvoline SynPower 5W30 and a K&N oil filter for my oil changes every 3-4K miles or every three or four months whatever comes first after seeing the oil analysis that was done. The time you change your oil depends on how you use your 370Z.