How do I know the mechanic put in synthetic oil and not regular oil, besides charging me a lot more?
Trust. If you feel that way maybe time to move on to another mechanic.
You can have the oil analyzed…but it’s NOT worth it just find that out.
You either have to watch him do it…or do it yourself to GURANTEE they are doing what you asked.
If you are a chemist and have access to a well-equipped laboratory, let me know.
Otherwise, there is no good way to tell what kind of oil you have in your engine.
Actually there is a very good way and its available to anyone who wants to do a web search for oil analysis . Cost for an analysis is about $25 and it tells you quite a bit about the oil you send in . Including whether it is synthetic or not .
I specify what oil I want and watch them put it in. Mostly I change my own oil though. Oil analysis at about $25 per sample is a good idea to determine the change interval as well as pinpoint any problems such as coolant leaks, bad air filter, etc. Any large city will have a Yellow Pages listing under “oil analysis”. In my area there are 5 companies who do this. MOst rucking and construction firms have oil analyzed on a monthly basis. Doing oil analysis to determine if they put the right oil in is a waste of time & money.