GENERAL
Q Just wondering what your opinion is regarding oils that have been opened and are slightly over/still within their 4/5-year shelf life. Oils are Mobil 1 0W-40 and Castrol Edge 5W-40. The Mobil 1 is the one over its 5-year shelf life with a production date of June 2017 and August 2020 for the Castrol that has a 4-year lifespan. However, I’ve become aware that these timeframes are probably based on the oil being unopened. The Mobil 1 has been stored in the house whilst the Castrol has been in the shed. I rang Mobil technical, and they said it would be OK to use if drained next year. I explained it will have only covered 5k by then, but they couldn’t recommend leaving any longer. However, I forgot to mention it had been opened and now I can’t get back through.
I’ve poured some of each into a clear plastic bottle, mostly because I wanted to see if they were uniform in colour from top to bottom which they are. I did notice that both had bubbles present, the bubbles in the Mobil 1 dispersed fairly quickly but there’s still as I write a group of 7 or so remaining in the Castrol after 30-40 minutes after pouring. Is it natural for bubbles to occur from just pouring? Could this be an indication that the anti-foaming additives are becoming depleted along with a plethora of other additives.
A The deterioration of the oil will begin to take place at a greater rate once the container is opened. Reacting with the air will c
