How can I tell if my car's synthetic oil needs changing?

The manual for my car says change it every 5,000 miles or every 12 months, whichever comes first. I'm nowhere near 5,000 miles (got about 2,000 left), but it's been almost 8 months. I took it in at 6 months for a change, but the dealership wouldn't change it and said it wasn't necessary. This hasn't been a problem before, because once upon a time I drove 5,000 miles in about 4 months' time. But now, I live in Boston and I do nothing but stop-and-go driving, and I drive less than 5,000 in a year. The oil level is fine, but I'm not sure what to look for with the oil itself to determine wether or not it needs to be changed early.How can I tell if my car's synthetic oil needs changing?
Look at the oil itself. If it is dark and dirty, replace it. If its still clear, you're fine. City driving really puts a strain on the engine more than highway driving.How can I tell if my car's synthetic oil needs changing?
There is no indication by simply looking at your engine oil to determine the condition of the oil.





If in doubt, change it out........
I would not worry about it, My Buick has a change oil light that comes on when the oil needs changed based on driving conditions. The owners manual states to change the oil at least every 12 months. I would change synthetic oil after 7500 miles or 12 months.


Your owners manual is referring to regular oil,you can push synthetic blend a little more and full synthetic even further.


You can't tell by looking whether oil is bad or not you have to send a sample to a lab to have it analysed like they do diesel locomotive and ships diesel and turbine engines.


If your oil is dark it is normal carbon buidup in your engine and not a indicator of the condition of the oil
Take a business card that is pourous, put a dab of oil off your dipstick on it. The oil will be soaked into card leaving dirt and whatever particles that are in the oil. If it is too dirty change it, you will see what I mean if you try this.
you should be fine with full synthetic. You didn't say what brand it is. I use Amsoil in all 3 of our vehicles. It recommends 1 year/ 25,000 mile oil drains. here's an interesting link that discusses how Europeans have gone over 10,000 miles on oil for years: http://www.amsoil.com/redirect.cgi?zo=14鈥?/a>