how can you tell if the oil they put in is synthetic

--you have to watch these guys<ul><li><a href="--">--</a</li></ul>

nt

If it thickens its not synthetic.

Synthetic oil runs much, much cleaner than the average dino oil. If the oil is less no more than a day or two old... it should be pretty clean. Pull the dip stick and clean it on a white napkin/cloth. If it shows up relatively clean and clear (light brownish color)... it's most likely synthetic. If it's dark/black... it's probably dino.

I once helped a friend change his oil from dino to synthetic *one* day after he got it back from service. When I dino drain looked terrible! It was extremely dark in color.

Cris