A family member always get her oil changed every 5K miles at a local Toyota dealership. She has been doing business there many years. All of a sudden they raise there oil change prices. Stating they changed over from Castrol GTX to the more expensive higher quality Castrol Synthetic Blend because of some issues they had with previous oil. My first thought was Toyota sludge motors. Question is do you think Castrol Synthetic Blend will help the situation any over GTX regarding some of Toyotas sludge motors?