THE DRIVE TOWARD THINNING ENGINE OILS

[PandaBear]

The biggest problem with reliability is design and the manufacturers' attitude on what to build. I wouldn't trust a company from Britain building exotic sport car to make reliable engine that last 300k miles running 10w30. I am ok with a boring appliance car company in Japan doing so using 0w8 engine oil if they historically can do that using 0w16 or 0w20.

Engine wear due to thin oil? If they design it right with the right flow they should be ok. If they use plastic on steel chain and didn't heat treat the parts correctly to save $5 here and $2 there then you are doomed regardless of 0w20 or 0w8.

If you mod your car with aftermarket turbo you shouldn't use what the OEM said anyways, you should follow instruction from the guy selling you the turbo and installing it for you.

 

[wpod]

One persons anecdotal evidence does not prove much of anything.

Thin oils are CAFE driven, not longevity driven, no matter how hard some want to belive otherwise.

It doesn't matter if other people let their preconceived get in the way of facts. The switch to lighter oil oils driven by CAFE and in Europe by the Carbon Dioxide limits. How do I know ? Because when I was gainfully employed I seemingly forever took continuing education auto classes at the local Jr. College [ which were actually great ] . GM would send their people over to teach their electronics and give the students inside information on the reasons why things are being done. I will add how many people wear out a well maintained vehicle? I usually say an auto trans breaks from low quality, marginally designed parts not because of the oil

 

[ssspencerjr]

Here's a little bit of info specific to my car. I have a 2017 Malibu, it has a 1.5 turbo DI engine. Oil cap, manual all say 5w-30. Now starting with year 2019, same car, same engine, they specify 0W-20. I have no idea why and I'd be curious if anyone here might be able to speculate.

 

[kschachn]

Here's a little bit of info specific to my car. I have a 2017 Malibu, it has a 1.5 turbo DI engine. Oil cap, manual all say 5w-30. Now starting with year 2019, same car, same engine, they specify 0W-20. I have no idea why and I'd be curious if anyone here might be able to speculate.

There’s probably oh, maybe a thousand posts where members have speculated about that. Perhaps you search around a bit.

 

[ssspencerjr]

There’s probably oh, maybe a thousand posts where members have speculated about that. Perhaps you search around a bit.

I didn't realize that. My apologies.

 

[kschachn]

I didn't realize that. My apologies.

But you did know what sends Bitog “into meltdown mode”.

 

[PimTac]

Here's a little bit of info specific to my car. I have a 2017 Malibu, it has a 1.5 turbo DI engine. Oil cap, manual all say 5w-30. Now starting with year 2019, same car, same engine, they specify 0W-20. I have no idea why and I'd be curious if anyone here might be able to speculate.

Sometimes changes are made to engines but only those who work on them or are involved in the manufacturing know about it.

The 2.5 Skyactiv in my 2017 Mazda is quite different from the 2016 engine but it is called the same.

 

[Blinker]

Regarding the 1.5T used in the Malibu. Starting with the 2018MY GM started calling for 0W-20. I believe 2018 was also the year GM made some changes to the piston design iirc. So yes, there can be design changes to an engine to coincide with a change in oil specification.

 

[ZeeOSix]

Here's a little bit of info specific to my car. I have a 2017 Malibu, it has a 1.5 turbo DI engine. Oil cap, manual all say 5w-30. Now starting with year 2019, same car, same engine, they specify 0W-20. I have no idea why and I'd be curious if anyone here might be able to speculate.

Use of thinner oils has been driven by CAFE for decades. Ford back specified xW-20 a long time ago on most of their vehicles, without any changes make to the engine design.

Regarding the 1.5T used in the Malibu. Starting with the 2018MY GM started calling for 0W-20. I believe 2018 was also the year GM made some changes to the piston design iirc. So yes, there can be design changes to an engine to coincide with a change in oil specification.

Even if an engine design is changed to better use a thinner oil (because the previous design suffered too much from thinner oil), it's all still ultimately driven by CAFE.

 

[Blinker]

Even if an engine design is changed to better use a thinner oil (because the previous design suffered too much from thinner oil), it's all still ultimately driven by CAFE.

Cool.

 

[alcyon]

My take on that interesting blog is thinner oils offer better fuel economy at the cost of shorter engine life. With advanced designs in the motors spinning and moving parts, I question if those engine designs can keep up with the oils as they get thinner.

I was always nervous using super thin oils in my powersport vehicles. The clatter of the motor when using 10W40 vs 20W50, 20W60, 30W or 50W is big.

I've recently switched from 10W-40 to the recommended 5W-30 in my truck and while my engines efficiency went up a bit so did the lifter noise. This is a big change for me. My last truck mostly lived on 20W-40 or 20W-50 and lasted over 300,000 miles.

Thick oil getting harder to find. Fortunately local motorcycle shops and online retailers have it available.

Thick oil still easy to find outside of US and Europe. Definitely regulations causing this.

 

[Job]

I had a couple air bearing dicing saws. The spindles never touch metal to metal. So what is it in a car that’s an issue with thin oil, the piston rings, tappets, camshaft lobes? As a cam lobe presses onto the lifter under spring pressure, what is the thickness difference between 0w and say 30? I would guess no difference.

 

[Jetronic]

Between an a5/b5 and a3/b4 oil the thickness difference can be 20% or more. HTHS viscosity relates directly to oil film thickness between 2 sliding parts at a given temperature. As oil temps rise the film thickness drops and when the surface roughness equals the film thickness, you will get contact, and wear.

between a 0w16 and a 0w40 there's a 40% difference in film strenght (2.3 cP vs 3.5 cP). And that's assuming you stay in grade...

 

[blingo]

Of course it doesn't just work that way for cam wear, it doesn't work that way for chain wear, doesn't just work that way for elevated shear rates beyond the million per second seen when idling.
So, while the 0W-16 and newer are of another realm (at least regarding main bearings), HTHS was not the answer. An acronym in fact more like a hint to start exploring what went wrong with that kind of reasoning and past developments.

 

[Job]

Between an a5/b5 and a3/b4 oil the thickness difference can be 20% or more. HTHS viscosity relates directly to oil film thickness between 2 sliding parts at a given temperature. As oil temps rise the film thickness drops and when the surface roughness equals the film thickness, you will get contact, and wear.

between a 0w16 and a 0w40 there's a 40% difference in film strenght (2.3 cP vs 3.5 cP). And that's assuming you stay in grade...

Sliding parts under strong spring pressure like the top of a a cam lobe? Last time I looked at cam lobes and lifters they looked "polished."

 

[Jetronic]

Cam lobes are notorious for operating in boundary lubrication regime. They will break through the oil film with hot oil, also because of the slow sliding speed. Maybe not when the oil is cold though. Higher viscosity oils will limit this metal to metal contact more than lower viscosity oils

 

[Job]

Cam lobes are notorious for operating in boundary lubrication regime. They will break through the oil film with hot oil, also because of the slow sliding speed. Maybe not when the oil is cold though. Higher viscosity oils will limit this metal to metal contact more than lower viscosity oils

So a 0w 16 or 20 when cold has the same size molecules as an 0w 30 or 40, but when the cam lobe gets hot the molecules are different sizes? Wouldn’t large molecules wipe off more compared to smaller? I just don’t get it. I suppose there is a whole bitog page reference going into it but how much time does one have when the owners manual tells what to use, anyway? I think the polished cam lobe was polished initially and after that it really didn’t change. On a Toyota engine with 200 k there was no visible wear to lobes, valve stems, valve ends, nothing but the machining marks partially removed, then steady state. I think it had bulk quicky lube and the cheapest oil filters nearly it‘s whole “life.” But frequent changes probably 3 k. Thanks for the answers.

 

[Jetronic]

Don't think of it as single molecule sizes The molecules are clinging together. More so when cold.

Think of it like freshly cooked spaghetti pasta. That would resemble hot oil. The pasta slides off each other and off your fork. When the pasta cools it sticks together and you can empty the pot by sticking a fork in it. Length of the pasta has a limited influence on this

 

[PandaBear]

Sometimes changes are made to engines but only those who work on them or are involved in the manufacturing know about it.

The 2.5 Skyactiv in my 2017 Mazda is quite different from the 2016 engine but it is called the same.

Very true.

Sometimes the engine software was changed, to avoid certain corner cases that will stress the engine for no reason (i.e. a 0.01 sec quarter mile reduction for a family car to rental car companies and 72 month 0% apr term) is all that is needed to reduce a lot of stress and improve fuel economy with 0w20 oil.

Or they figure out that finally all the oil on the market is Dexos1 approved, and they don't need extra thickness to protect against ping.

 

[1978elcamino]

Im thinking about blending my own -15w0. Anyone want to pre-order?