i was fortunate to find a maintenance log in my Z that the previous owner kept. nice to know how things were (or were not) taken care of.

the same oil and filters were used on the first five rounds:

2105 / 5w30 Mobil 1 / FRAM*
5020
8234
12180
15353

the last one at 17600 says 0w40 Mobil 1.

questions would be why the switch to 0w40...winter prep i am guessing...and if i do 3-4k mile change intervals, can i switch back to dino or am i stuck with synthetic?

i did research a bit and Mobil's site shows:

http://www.mobiloil.com/USA-English/...l_1_5W-30.aspx
http://www.mobiloil.com/USA-English/...l_1_0W-40.aspx

obviously the FRAM* filter has to go at the next change...






*

 

Looks like it was well maintained. You could switch back whenever you want. But why would you? Use a good filter like Mobil 1. Avoid the Nissan filter its now made in China!

 

You can switch from synthetic to regular motor oil whenever you want.

 

why would you want to switch back to regular oil? stick with Mobil 1 Synthetic, you get longer intervals with oil changes, and most z owners (not saying all) use synthetic. not sure about the oem filters being made in china but im using oem and haven't had any problems...16k miles on OEM Nissan filters & Mobil 1 Synthetic and still going strong : )

 

[QUOTE=pony_killer]why would you want to switch back to regular oil? stick with Mobil 1 Synthetic, you get longer intervals with oil changes, and most z owners (not saying all) use synthetic. not sure about the oem filters being made in china but im using oem and haven't had any problems...16k miles on OEM Nissan filters & Mobil 1 Synthetic and still going strong : )[/QUOTE

The OEM filter was made in Japan. Last week picked up one and its made in China. So I went with the Mobil 1 which is USA.