Z Oil Change: Miles or Time?
 

I will hardly drive my three week old Z 3750 very gentle miles in a whole year, let alone 3-6 months. (I have an Altima coupe for DD) So should I nevertheless change the oil based on time elapsed (3 months from delivery) rather than miles driven (which will be only about 300 per month)?
Also can I go to Mobil 1 for the very first oil change?

I'd just do it Spring and then Fall. Call it good.

You can go any 5W30 you'd like, including Mobile 1. Just know, its not a FULL synthetic. If you want one of those, the recommended brand would be Redline, due to the ester additives that these VQ motors like apparently.

Since the middle 90s I've been changing my 5W30 Mobil 1 every 7,500k or once a year, whichever happens first. When it comes out, it's cleaner than the regular/dino oil I used to change every 3,000k. I do agree with MightyBobo regarding the ester bit on 370s. But 350s take any synth' oil with no problemo. So, to be on the safe side, go the ester route.

M1 Extended Performance 15K is a full syn...it's what I've used...including their filters.

Even then...I don't have any reason to think M1 won't deliver as good or better when compared to what is also commonly available (ie, walmart).

With redline and such, I worry about the ester base absorbing too much moisture and so on, that they were designed for 1-2 races before being changed out. I know races are hard on the engines, but, my point being is that, for the long term (3750 or more miles / 3 or more months), that it won't do as well as something like M1 or similar oils.

Bingo!

Also, Mobil1 oil is fully synthetic...

Mobil 1 5W-30

I had a cobra (garage queen) that was driven maybe 1-2k mile a year. I changed the oil with mobil one every 6 months. If I remember correctly you need to wait to switch to synthetic to let the engine seals break in.

Ester absorbing water is based on its % which is why its blended the way it is in the Nissan Ester oil. That oil in not designed to be changed out after a very short usage period.

A good rule of thumb though regardless of what oil you use is to change twice a year regardless of milage. This is to avoid moisture build up (dino or synthetic). Typically people do this Spring/Fall as most light useage vehicles are driven more frequently or only during the summer months so a change at the begining of the "driving season" and the end is prudent.

Should I then wait for the fall (second) oil change (maybe 3500 miles on the odometer by then) to go to synthetic, right?

I always waited until 5-7k miles to switch to mobil 1. I'm sure it won't hurt to do it earlier. I have 2700 on mine now and it's on its 2nd oil change. I'm going wait until 5k and go mobil 1.

The Redline Racing oil is designed to be swapped out frequently. The regular Redline synthetics (such as 5W-30)are intended for street use and, as such, should be fine for typical synthetic change intervals. I have been using Redline for years (first time was 1988) and have been very satisfied with every 8000 miles/once per year. My Z is a seasonal car. Last week, before the Saturday night storm in the Northeast, I changed it out prior to going into hibernation. Every two weeks or so (when the streets in my neighborhood permit), I will cruise around for ~30 minutes. This routine has worked for me for a long time. Gets rid of flat spots on the tires and runs long enough to burn off moisture, etc. I have never pulled the engine apart for empirical evidence, but my engines have gone 100k plus with no issues.

BTW, FWIW, after I put Redline in, it was definitely quieter than before. Less of the annoying valve train chatter.

Miles. I think the whole thing about every 3 months is a sham..... Does anyone really know how long the oil was sitting in the container prior to you purchasing it, and dumping it into your engine? Oil doesn't just break down because it sits around (if it does, it is going to be so little that you will never see a difference). You already said that you drive it easy, so if it looks in good condition, just go with the miles, and don't worry about the months.

Very interesting analysis. I would self-impose a 12 month timit, though, of maximum between changes though, irrespective of how few miles. I'm sure you would agree.

3K / 3mo is a sham. That said, once you introduce your oil to your engine, and all that it goes through...it's not unreasonable to say that it needs to be changed at least once a year, if not 2-3 times.

I read somewhere that the time to change your oil basically goes around the winter months if you drive it a lot. Late fall, early spring, since that's when the oil will collect and retain moisture due to the colder temps not letting the oil get hot enough to burn it off.