Getting ready for an oil change this weekend. I need 6 qts of oil and have two 5 qt jugs of Mobil 1. One his a high mileage 5W-30, the other a 0W-30 AFE. I reached out to Mobil and asked about mixing 5 qts of the AFE with one quart of the high mileage. Here is their response:
"Thanks for writing to us. All of our oils are formulated to be chemically safe in combination with each other. We do not, however, recommend mixing SAE grades. The SAE viscosity numbers measure physical flow rate characteristics, rather than chemistry."
Besides thickening up (a bit) the 0W-30, what's the downside? Any guesses on what's behind their take on mixing the two viscosities?
"Thanks for writing to us. All of our oils are formulated to be chemically safe in combination with each other. We do not, however, recommend mixing SAE grades. The SAE viscosity numbers measure physical flow rate characteristics, rather than chemistry."
Besides thickening up (a bit) the 0W-30, what's the downside? Any guesses on what's behind their take on mixing the two viscosities?