I was out of town and needed an oil change. Went to a national garage. they insisted I need synthetic oil. called my dealer They agreed. When home I checked receipts. they used regular oil except twice in the last couple changes. Do I need synthetic oil and will mixing the two oils damage my engine.? Thank you.
The oils will mix just fine and it possible that the receipt is just a generic print out and you actually got what you wanted . I would not worry but next time just explain what you expect to be done.
Two words…Owners Manual. Ok, well, more words. And if you don’t have one get one almost all your answers to questions regarding the vehicle you own are in there. I think I see why it’s called an “Owners Manual”.
The maintenance of one’s vehicle shouldn’t be a mystery, but–fortunately–the mystery can be cleared-up by simply looking at the booklet that should be sitting in the glove box.
That being said, if only “conventional” oil is specified in the manual, using synthetic oil will not hurt anything… except for one’s wallet.
Synthetic blend oil is a mixture of regular oil and synthetic oil.
READ THE MANUAL.
It’ll clearly state in the manual what oil is needed.
My 14 Highlander oil weight is 0w-20. That weight oil only comes in synthetic or blend.
Hm. The dealer agreed you need to use synthetic yet failed to do so until recently? If the owner’s manual doesn’t state that synthetic is required then perhaps there was a TSB or other advisory issued by Toyota suggesting the change. Ask them.
From the 2009 Highlander Hyrid owner’s manual:
SAE 5W-20 or 0W-20 SAE 5W-20 or 0W-20 engine oil may be used. However, SAE 0W20 is the best choice for good fuel economy, and good starting in cold weather.
It doesn’t seem to say anything about synthetic vs regular oil although, as noted, 0W-20 isn’t available as regular oil.