I have a 2012 highlander limited. I change the oil at 0.5k during the break-in period. I was told that toyota uses special break-in oil on new cars and I was recommended against oil change (I placed a call to toyota website, a lady asked around and told me that no, toyota does not use special break in oil, also, Emund on 2011 states that only Honda uses break-in oil). I did the oil change anyway at the dealer. Unfortunately they put full synthetic oil in my car and now I'm having worse MPG, 15 on mixed driving. I'm under the impression that synthetic is not good for break-in period due to low viscosity. My question is: should I change back to regular oil for the break in period until 5k, then switch back to synthetic? Can I use third party break-in oil like Royal purple or brad penn? Does it matter now for break-in since I've already had close to 1K ?
Hello, and thank you for letting us help you with your automotive question. There is not a break in period that is recommended by the manufacturer on this vehicle. You can use a break in oil for the first couple thousand miles, but it is not recommended. The recommended oil in this vehicle is 0W-20. If you are getting worse mileage then it is possible that the dealer used the wrong bulk oil.
using break in oil is not recommended because it will hurt the engine or what? I think that's the centerpiece of the question. Also is 0w-20 only synthetic or there is conventional version of it? Do you have any break in oil brand to recommend?
Also some source at Toyota saying genuine toyota 0w-20 has "special additives" that's not interchangeable with other oil. Is that true or just rumor?
These engines generally do not require any type of break in due to the way that they are built/designed. This is why there is not recommendations also on the proper way to drive the vehicle to break it in. If you use break in oil in some vehicles it will actually damage the engine and cause it to burn oil over it's lifetime. I do not see that on this engine though. Royal Purple is usually my choice in break in oils though. As for the 0W-20, you can use other brands besides Toyota and mix them, and there are some conventional versions of this also.