I took my roadster into the dealer to have my first oil change today. I brought my own oil, Mobil 1 15w-50. When I got there, the service manager recommended that I do NOT put the Mobile 1 in the car yet. My Z only has 1600 mi., but, I wanted to get the factory oil out now that it has been 'broke in'. He told me to hold off on the Mobile 1 until after 12,000 mi. because this is when the engine has been completely broke in. According to him, a petroleum based oil has a better lubricity during the break in period. This was not in any way a ploy to squeeze more $$ out of me since the oil change was free either way. Anyone have any thoughts on this??

 

Although there are differing and strongly held opinions, most engine builders will say to use regular oil in the engine until it is fully broken in...metal bearing surfaces will mate correctly... and then switch to synthetic. I have no way of testing this and I have obtained 200K using regular oil on the past few cars without burning oil.

FYI: I heeded the advice and waited until 12,000 before switching to Mobil 1--Now have 35,000 miles on the car.

 

I had the same situation with my dealer, free oil change as well. He said to wait until 10,000 miles. Ok, no big deal.

 

FWIW, my dealer's service manager said to hold off on synthetics until about 12,000 miles to insure a complete wear-in. In fact, he warned that the use of synthetics earlier than that might void the engine warranty.

This service dept. did a great job on my 1990 300ZX for several years, so I'm inclined to believe them. Besides, their incentives would seem to be fairly well aligned with mine on this front.