[G]

I just changed the oil in my car (94 Z28) and noticed that the oil was really thin. I use Mobil 1 10w-30 on a regular basis. The oil seemed to have a really gassy smell to it. As far as I know the car is running in pretty good condition and the gas economy hasnt changed in the car whatsoever. I have talked to a couple of people about this and they told me that it is pretty normal with Mobil 1 to smell like gas when you drain it. Has anyone else noticed this? I think I am going to change to Valvevoline on my next oil change.

 

[Glock30]

I think it'd be somewhat normal with a "true" synthetic oil since it doesn't absorb the gas blowby like a conventional oil. I could be wrong but I doubt that the oil is the problem if there truly is one, try doing a leakdown test to see if you have a problem with your rings

 

[MDV Synthetics]

You could also send your oil out for analysis. That can help pinpoint exactly what is going on in your engine. Fuel in the oil is bad whether it's synthetic or not. If there actually is fuel present it indicates a problem.