Resurrecting my own thread...

Time for a second change with 0W-30 and... I can't find any, other than Mobil1! I was hoping to try Castrol but now it seems they're all going to 0W-40...

So, I went ahead and used Mobil1 but now I don't know whether to stay with 0W-30 Mobil1, or try 0W40, or 5W-30...

Sigh...

STOP IT!



You're just confusing the newbies even more - :rolleyes:


humfrz

Are you really struggling to find 0W30? Catrol, Amsoil, Red Line, Motul, Shell, etc.
It's a quick google/amazon search.

So far, the only place I can find 0W-30 is at Walmart and even then it's just the 5qt. bottles. I was trying to avoid purchasing online right now because I'm kind of between houses now so arranging to be at my house to watch for delivery is a PITA. I guess in the future I'll have to go online...

https://www.oreillyauto.com/search?q=0w-30

https://shop.advanceautoparts.com/we...ExactFit=false

https://www.pepboys.com/search/?text=0w30

Any gas station may randomly have 'em.

The 0w-20 is recommended in large part because the AVCS uses the oil to do its thing. There are very fine tolerances involved and the thinner oil is designed with that system in mind. All vehicles are tending towards lighter oils as they become more efficient and have tighter tolerances and some sort of variable valve control.

The OP's anecdote is just that- anecdotal. The engineers who made the FA20 engine know a lot more and made 0w-20 the recommended oil for a reason. The engine in this car bears little resemblance to your dad's car back in the day and a lot of what he used to do will shorten the lifespan of your 86 today.

Subaru has been doing variable timing way before 0W-20 became so popular. For example there were Subarus with AVCS in 2008 and the owners manual lists all the way up to 10W-40 as an option and 5W-30 standard. Obama made 0W-20 popular along with any other BS thing that gives someone 0.0002 more MPG out of desperation. If it messed up the timing then manuals for other markets wouldn't even list 5w-30 as an option.

I just recently decided to change oil weights again (still sticking with Mobil1)..I went to 5W30 at 15K miles for better heat tolerance of occasional track days. However now at ~55K miles, I recently bumped to 0W40, not for better heat tolerance/viscosity, but rather a little bit better cold start pumpability. I live in a place where it's not unheard of to hit -10 deg F in the winter, and still push high 90s+ in the summer.

I'd also read on BITOG that the gold cap/Extended Performance versions of Mobil1 were the ones to get, as that particular additive package contained more cushioning metals than the 'standard' one, and I think the PDS backs that up if I recall correct. So I'd been using 5W30 XP, but I haven't been able to find it yet in the 0W40 version - just standard 'Mercedes spec' oil. I wonder what I'm giving up...

0W-40 is thicker than 5W-30 at all temperatures. How does it pump better in cold temperatures?

Where is this information about AVCS published? There's nothing magical about the system. Ports, valves, check valves, apex seals...

OTOH, the owner's manual specifies 5w30 and the Japanese one goes even thicker.

Can you provide some information how 0W-40 is thicker than 5W-30 at all temperatures. At very cold temperatures 0W-40 is thinner that's why it is listed as 0W.


I have been using 0W-30 for about 40k and according to my oil analysis my engine is in great condition. I recently made a switch to 0W-40 at the start of summer, I will post that oil analysis on this thread for comparison. I also spoke with at Mobil 1 on the phone to get more info before I switched to 0W-30. Also on their website they listed 0W-30 as being an approved oil for the FA20. I've had the FRS for years and logged 78k, using mostly 0W-30. I suggest doing the research yourself and taking everything into account before switching oil, rather than just doing what others say or sticking to the manual's 0W-20. The right oil for you may vary depending on your climate and application.

Plugged the mobil specifications in here, https://widman.biz/English/Calculators/Graph.html at -4f 0w-40 is thinner than 5w-30.Oops:bonk:

SAE Grade 5W-30
Viscosity @ 100ºC, cSt (ASTM D445) 11.0
Viscosity, @ 40ºC, cSt (ASTM D445) 61.7

SAE Grade 0W-40
Viscosity @ 40ºC 70.8
Viscosity @ 100ºC 12.9


Mobil only lists MRV for the 0W-40 and not the 5w-30. I think the real comparison for oil pump ability when cold is MRV and CCS from my understanding.

I must be doing something wrong. I go 10,000 miles between oil changes using 0W-20, and I didn't need to add a drop of oil during that interval...

Interesting, I just assume the 0 weight is less viscous than 5W at cold temps. Not sure how that website caculates these values but it seems like there is a range rather than a set value.

For example in my 0w30 analysis I posted earlier the cST viscosity at 100c is at 8.74, which is within the range. It also lists the expected range and the highest (8.5-12.4). The site you linked states a value of 12.9 at 100c. So I'm still not totally certain 5W-30 is less viscous than 0W-40 in all tempatures but it's worth looking into, I'll do some more research (mostly because I enjoy learning about oil). But you make a good point for me to look into.

In any case I personally feel more comfortable with higher viscous values in thinking with that I get more protection, however most engine wear happens on start up so cold start up viscous values are important. Which is why looking into this more is even more interesting.

In the near future I want to get the dual radiator/cooler from JR which is supposed to warm up oil faster on start up which could also affect what oil I use later after I get that.