Yet another oil temp thread (this one's good...)
 

Ever since changing my oil, I've noticed that my oil temps are not as high as they were before.

I mean the temp will sit at around 200F - where before it was around 220F!

Now, I figure this can be accounted for with one of two things:

1) Swapping OEM fill with Mobil1 5W-30 - the standard stuff from a 5qt jug
2) Swapping the OEM oil filter with a Mobil1 M1-110 Filter.

Now, the M1-110 filter is a slightly larger oil filter than the OEM size, where they spec the equivalent of the M1-108 filter.

What I'm wondering is if the increased filter area is allowing for better flow rates, which in turn keeps the oil cooler by moving it around and flowing through the valve-area faster or something along those lines?

Anyhow, it does get up over 200F, on up to 220F if I push the car a little.

More testing is needed, but, if this is a trend, then that could indicate that the factory fill oil doesn't flow well, and the OEM filter also doesn't have decent flow rates...

Thoughts?

The other thing to realize is the oil filter can act as somewhat of an oil cooler and by putting a slightly larger one on it might cool the oil a hair more. However I highly doubt it cools it much if any and if so there probably wouldn't be any measurable difference.

I would doubt it too...And as far as restrictions there should be hardly any. Oil type and break-in miles are the real reasons..(as discussed on other threads and well documented at this point.)

Doubt its an issue of flow, since the factory fill is also a 5w30. The synthetics do flow better in extremely cold but for normal temps, it shouldn't be significant. Someone mentioned its due to break-in, but if it is, it would seem that he would have noticed it more gradually as opposed to right after changing the oil (all else equal). Could you confirm if the temps went down immediately after changing the oil or over time?

Immediately. I drove around last night again and it stayed around 200F. With a bit of "spirited" driving, it went up near 220F, but it does for the most part stay around 200F.

Could be weather related too, temps outside have been a bit lower than before I changed my oil - but, not enough (I would think), to justify the difference.

Also, on break-in, I've got 1356 miles on it as of last night...

Most likely temp related. I wish it were that easy. :(

A 10F ambient temp can make a 20F difference?

The level of heat soak, before starting the test, can also play a role.

I would give it a couple more weeks and monitoring your temps under all different condition, and see how things settle out. But at the end of the day, the 370Z needs a massive oil cooler upgrade.