As the title says - any reason NOT to? I think a fair number have at least switched to 5w30, but the only difference between that and 0w30 is even better cold temp viscosity - the viscosity is the SAME at operating temperatures. Engine protection in general from an oil standpoint seems to be about oil flow and film strength. Don't really see why guys run 40 weight oils in their stock motors.

90% of engine wear is during cold temp - and cold temp doesn't mean freezing - I guess technically it would be any temp colder than operating temps. Even a hot summer day, the oil after the car's cold is too thick to provide appropriate engine wear protection. Your area doesn't need to reach freezing temps to benefit from a 0w oil.

If you're wondering, yes I did recently just re-go through BITOG's motor oil university What do you guys think? I can't really think of a reason not to use 0w30. I don't think the oil is "too thin" - at cold temps it is still too thick to adequately protect a motor, and at operating temps it is the same as any 30. I'm talking strictly about synthetic oils, but not necessarily Amsoil.

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Pros

- Flows much better on start up
- Thus reduces cold-start motor wear, ~90% of where all engine wear comes from
- Provides same viscosity & film strength at operating temps

Cons

- ??

Misconceptions

- 0w30 is "too thin" for our cars - false, is the same viscosity at operating temp. Flows better on startup, which is a good thing

 

I use mobil1 ow40 and i have no problem yet for 10k miles ! Idle pressure = 15-16,

 

I would like to hear what others have to say as well. I hope it stays on topic and gets technical rather than the typical oil threads on here.

Anyway I have always wondered the same thing and was recommended to run 0w30 in my car a while ago. Its been about 4 years now and ~35000 miles for me using 0w30. I used Castrol Syntec 0w30 (European formula) which I heard good things about a couple of times but the rest of my changes have strictly been Amsoil SSO 0w30. Unfortunately I have never had my oil sent in for an analysis, so all I can share is that my cars seems to run fine and hasnt blown up yet

The car is driven year round in New England so temps vary from as low as 0 to upwards of 90 in the summer. I only use one weight oil year round and have been doing so for over 4 years now and dont see any reason to change my routine, unless anyone here can chime in and tell me otherwise.

 

hopefully so - I might compile any data in the first thread, pros, cons (if any), misconceptions etc. as it stands though, i cant think of any con.

have you ever consumed any oil?

 

You know its funny that you mention this, I am actually trying to track down an oil loss issue. I dont think my car is consuming the oil but rather is leaking it however I cannot pinpoint where its coming from. It looks like its coming from the passenger side by the timing cover but I'm not sure. I never see oil on the ground, however my engine is definately showing signs of an oil leak because its really greasy on that side on the front and back of the block not to mention the fact that I need to add about a 1/2 quart between oil changes 3-4000 miles. Im almost positive that its not due to the weight of the oil though because this only started happening about a year ago. Different topic, different thread.

 

I use SSO 0w-30 on a stock motor, and will be switching to a thicker oil like a 0w-40. The reason being I plan to track the car more and get stickier tires, and would like added protection from oil starvation. 0w-30 is more likely to slosh to one side of the oil pan in a sweeper, a known evo issue, while thicker stuff will stay in place longer" giving me that added protection. That is one instance were I feel SSO 0w-30 is "too thin" and warrants a change in my case.

 

So that's one instance where the higher viscosity actually benefits - though, isn't that more of a band-aid? I added the Kiggly HLA and (plan to) run a BR baffled oil pan or something of that nature for that. According to BITOG, I guess in terms of oil protection, it's all the same until you get very hot, but even then the differences are minimal and most of the focus should be on how much oil flow you're getting, and something like 10psi/1000rpms? Idk I'm not an expert.

Also, when the oil gets to operating temp, that's more of a benefit of the 40 grade (the higher viscosity) than the 0 part of it. In other words, it would make no sense if one were switching from 0w30 to 10w30 for track because of the higher viscosity (there is none), which isn't what you're doing

 

Yes, the thicker oil is more of a band-aid than one of the more direct solutions you listed. But it's one I'd continue to run even if/when I do go to a more direct solution, just for that slight peace of mind(of possibly a split second or added .00?G before oil starvation) I perceived it may give me on a tracked car. My wife's X will continue to use Amsoil's SSO 0w-30.

 

I guess then, for your instance - is there any reason you would run a 10 or 5w40 as opposed to the 0w40? I can't think that there would be

 

No reason to me, I too like the extra startup protection.

 

I run the SSO 0W30 in my track evo with the HLA and I also run one quart over spec. I haven't had any starvation issues (that I know of) in 110° F on track temps. I don't have my oil temp gauge installed yet (it gopes in once my build is finished) so I don't know what my on track temps have been.

Once the build is finished, I'm switching over to 10W40 premium protection as per CBRD's recommendation. I assume the zinc is a good idea.

 

Built motor? Why not the 10w30 zrod? After re-visiting all the BITOG stuff I think I won't be running a heavier oil for a while.

In general though, do you see any reason why someone should run a 5w or 10w over a 0, given everything else equal?

 

Build, not built. It's a laundry list of modifications, the block and head are untouched.

I do not, no. Especially not here in CA near sea level.

 

With built motors it's best to go with the builder's recommendation, because of the differing tolerance of each.

 

the more differences between the numbers (0w-40 vs 10w-40), the faster the oil breaks down and needs changed more often. thats one drawback, but i dont know exactly how much more often