First, the GTX you have been using is great oil and you will have no trouble with it. Now to answer your question. Synthetic -VS- conventional oil:
The difference lies in the fact that synthetic motor oils are created utilizing a specially "synthesized" base oil where the size of the oil molecules are all of an ideal weight and of a consistent size. A conventional motor oil is made up of different molecule sizes which are mixed together, along with various waxes and impurities. A fully synthetic oil is made to provide a much purer base oil, with less waxes and with a uniform ideal particle size to help increase the oils viscosity level.
The additives which are used in the production of synthetic oils can help to create an extremely stable engine oil which will sustain the correct viscosity levels across a large range of temperatures and which will flow properly at lower temperatures when compared against conventional oils. Additional friction inhibitors which are activated at lower temperatures than those of conventional oils, are generally included in synthetic motor oils, to provide improved protection for the engine from the moment of start-up.
This means that the synthetic oil is designed with enhanced viscosity protection to help prevent engine wear, reduced heat breakdown volatility for decreased oil consumption, can actually improve fuel mileage, is easier on engine cold starting, and helps reduce in engine deposits.
As far as your car, it will take SAE 5W30 up to 86 degrees F. Above that Volvo recommends SAE 10W30. Also, Volvo recommends synthetic oil IF you are driving in sustained high or low temps, towing, or always driving through mountains.
One last thing. Since you do your own work, your other cars would have most likely reqired DOT 3 brake fluid. The Volvo requires DOT 4. Don't mix them. Also, when you change the oil with a new filter, the system should hold 6.1 U.S. Qts. Of oil or 5.8L.
I hope I answered your questions. If you have others, let me know.
Thanks for using 2carpros. Com
Monday, October 12th, 2009 AT 9:33 PM