So I had the oil changed on two cars after about a year.
One had M1 0w40 before and after, and it was a 6k interval. The oil was quite black, but as we know that oil can last much longer than 6k. It's the MB 5.5 V8 engine. The new oil was GF5/SN, the old oil might not have been.
The second went from Valvoline Synpower to Quaker State Ultimate Durability, both 5w30. It did 3.5k. Oil was not as black. Both oils were GF4/SM.
But both cars were noticeably quieter after the oil change.
What is the reason? Is it due to shearing and the fact that the new oil is now the correct weight?
One had M1 0w40 before and after, and it was a 6k interval. The oil was quite black, but as we know that oil can last much longer than 6k. It's the MB 5.5 V8 engine. The new oil was GF5/SN, the old oil might not have been.
The second went from Valvoline Synpower to Quaker State Ultimate Durability, both 5w30. It did 3.5k. Oil was not as black. Both oils were GF4/SM.
But both cars were noticeably quieter after the oil change.
What is the reason? Is it due to shearing and the fact that the new oil is now the correct weight?
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