So recently in my country so many Toyota and Lexus Users here have been rattling about the knocking sound in their engines after changing their engine oil.
The problem is usually from the users and their mechanics not from the car manufacturers as they switched from recommended 5W20, 5W30 Fully Synthetic Engine Oil or semi synthetic to 20W50 because of Kazeem mechanic and maintenance costs of 5W30 Fully Synthetic due to the rising cost of petrol and petroleum products just to save cost.
As if that's not enough, they removed the thermostat in their car, citing hot weather 🌡️☁️ in Nigeria and Because the 20W50 is a very thick and high viscous oil, it has a very poor flow rate coupled with the fact that the engine is running cold 🥶, it cannot lubricate the engine very effectively as it should there by causing the sound most drivers hear on their engines.
That's why most of these engines 2AZ, 2AR, 2GR, 3MZ, 2ZZ, etc have the knocking and rattling sound on cold start when the car has not been running.
If you must use 20W50, ensure your car cooling system is running effectively according to manufacturers threshold so that the optimum temperature from the engine can help improve the flow rate of the 20W50 in your engine
2GR, 2AR are prone to Camshaft Gears rattling, don't compound it by using unrecommended high Viscosity engine oil for running the car as it's result effect of the life of the engine could be detrimental.
It's shameful using 20W50 on 2013 RX350, 2015 Highlander etc, Most of these Kazeems mechanics aka road side mechanics have no respect for Toyota and Lexus unlike Benz citing the car is strong and it easily adapt to change in manufacturers recommendations.
It is recommended that one Stick to the recommended engine oil for your car and enjoy optimum performance as Bad oil is the reason why engines doesn't last one or makes funny sounds which is uncomfortable to the users.
Do the needful now or cry to the market for a new engine, when u fail to do the right thing.
Have a lovely day and stay blessed