I have always had the oil and filter changed on my 2004 Toyota Avalon every 5,000 miles at a Toyota Dealership. Previously I have always changed the oil in my cars myself. Now at 160,000 miles I decided to change the oil in my Avalon using a OEM filter and decided to used Mobil 1 full synthetic oil. But with the shortages of many things, the only Mobil 1 full synthetic i could find was the high mileage oil. The information printed on the container indicated that the oil was designed to be used in motors exceeding 75,000 miles and among the benefits listed said that it helped to restore the seals. Now, this car does not burn, consume or leak oil and the oil is still fairly clean at each 5,000 mile change.
I have since read online that once you switch to a high mileage oil, you must continue to use a high mileage oil for the remaining life of the car because this oil causes the seals to "swell" and reverting back to non high mileage oil will cause the seals to leak because they will no longer stay swollen. Is this true? Have I messed up my 1MZ-FE V6 that had no known problems. Can I switch back to regular full synthetic or should I continue to use the high mileage full synthetic.
Thank you, Tommy
The high mileage oil won't hurt anything, it just contains some seal conditioners. There have been times I've used the high mileage stuff if it's all that was on the shelf and then switched back later with no ill effects.
That is what I was needing to learn...from someone who had actual experience with using high mileage oil and then switching back to 'regular' with no ill effects. I am relieved to know this and will no longer worry about it.
Thank you so much for your response.
Do not waste your money on that oil. Just use what is recommended for your car by Toyota.
Thank you for your advice.
The Toyota dealer sells oil too just by there filter and oil
