Thinner motor oil?

[Baltothewolf]

Originally Posted by 14'ecocruze

Just curious on the whole thinner oil subject. I k ow this seems to be more focused on the green or next oil, but if a vehicle is driven ecomodder style wouldn't it be assumed we could go with a thinner oil. I have the 1.4l turbo Cruze. I want to switch to 0w20 since my car is typical to only do short trips so cold start efficiency is a must. But I drive so lightly that I feel I could go thin regardless. Could it be detrimental to my turbo even though I rarely enter any boost.50 mpg+ typically on 13 miles commute. Just looking for a little input. Thanks

Put the highest quality oil of the manufacturers recommendation in. I would never, ever run thinner than manufacturer recommend oil on a turbo motor. What you could do is drop the w weight, but the warm viscosity I wouldn't mess with.

Example, on my Miata manufacturers recommendation is 5w-30, I went to shell Rotella T-6 which is 0w40. W rating is ok to drop a tier or two, just be conscious at cold startups not to rev to much, but the warm viscosity I would never ever go down, only up 1 tier.

[ecocruze]

So you recommend a 0w30 then vs dropping to 0w20? So even running such light load on engine you still suggest refraining from dropping to lower viscosity at temp oil yet. I assume your basing this primarily on the fact it's a turbo engine? Guessing you would also suggest no EOC as well?

[Daox]

You can try thinner oil, just be aware your engine was not designed for it. I would get a baseline of how your engine normally wears before testing thinner oil. Thinner oil will almost certainly wear your engine faster. How much faster is the question you need to know as the owner. To know this, you must have an oil analysis done when you change the oil.

[Frank Lee]

FoMoCo retroactively approved 5w-20 for many of it's older vehicles that originally specified 5w-30. Just a few days ago I changed the 'Racer over to 5w-20. All indications so far are OK.

[ecocruze]

Originally Posted by Frank Lee

FoMoCo retroactively approved 5w-20 for many of it's older vehicles that originally specified 5w-30. Just a few days ago I changed the 'Racer over to 5w-20. All indications so far are OK.

I think it's just hard for me to grasp that these full size trucks are running 5w20 while a little baby 1.4 needs 5w30? Makes no sense to me. Im all for thicker oil for higher demand/load but my putting around Cruze that does zero towing. Maybe a bag or 2 of Crete in the trunk every once in a blue moon. The little pop can turbo really generates that much heat even when providing virtually zero boost. I typically accelerate between 0 and 12 vaccum... typically closer to the 12. I touch boost of 1-2 going on one uphill stretch momentarily on my daily commute. Race cars heavy pulling trucks are going thinner I don't make sense of it. My old jeep I put a gallon of Lucas in it cuz it burned oil so bad. Didn't need to add oil between 3500 mile oil changes anymore, but that's a vehicle with over 250k hard miles. Sorry for the rant. Fyi wife's expedition has the twin turbo v6 which is what really got me intrigued by oil viscosity for turbo engines. Twin turbo makes a little more sense seeing as they aren't miniature.

[Daox]

It has to do with how the journal bearings inside the engine are designed, their bearing surface area vs the amount of torque being put through the joint. Thinner oil requires more surface area to hold the same pressure.

[Stubby79]

You'd probably* be just fine...right up until you get in a huff, stomp on the gas, and spin a bearing.

I like the idea of thinner @ cold temp oil though. That makes a lot of sense. Trying it myself, with positive results so far.

*Attempt at your own risk

[ecocruze]

Love this page. Thanks for the fast response guys. I think I will run the 0w20 at my own risk for this go around and for future just run with 0w30. I doubt I'll have any issues as I have seen a few oil analysis from others who have run 20 in theirs. Only 2 and I believe both changed at under 6k miles. Analysis we're everything in normal range for wear. Anyways can always lean toward a thin 0w30 if there seems to be any mpg improvement that's significant. Will be hard to tell as I will be switching to 91&93 octane here soon. Found after 2 months of 89 e0 that switching back to 87 e10 is night and day with this car. Boggy express. Along with 2-2.5 mpg decrese. 89 paid for itself. Only need 61 mpg for premium to pay for itself. Wish me luck ��

[Ecky]

At the very least, I think going with a lower winter weight would be safe. Your owner's manual says 0w30 is fine.

[101Volts]

I'm not checking the thread today to see if anyone said this but not all 0w30s and 5w30s are alike, motor oil numbers are general terms meant to describe viscosity ranges and they can vary. For one common example Pennzoil Platinum 5w30's literally thinner when cold and hot than Mobil 1 0w30, the publicly available data sheets tell this. Even oils within a brand's product line can vary, Shell T6 comes in 0w40 and 5w40 and they're both different at the same temperature; 0w40's the thinner one.