This is along the lines of the heaps of oil “reviews” on Amazon. “ I change this oil at 5k and it came out the same color as when I put it in!! Awesome oil, 5 stars!!”
How Thin Oil's Kill Your Engine, the Magic Mechanic Show
- Thread starter Joenpb
- Start date
665,000 miles on my original engine in my Accord using 5W-20 almost every single time... maybe it just needs more time before it kills it... 
From what I understand, having the cylinders deactivate causes oil consumption due to the rings having zero pressure/tension on them. Regardless of cause, I do not want a vehicle with cylinder deactivation. I have seen my father as well as some friends have some issues because of it. All of them consumed oil.
Deactivated cyllinders also starve the bearing and cam shaft of oil. Leading to worn lobes and valves that don't fully open or close. I've known a few people who've had this issue, and needed new engines. The fuel management system can be deactivated with software.
Thinner oils (less HTHS viscosity) don't give as much MOFT between moving parts, therefore there can be more wear over time. Running thinner oil isn't about "damaging engines and resulting in dead cars on the highways" ... it's about not providing as much wear protection than thicker oils. More HTHS means more MOFT and therefore more wear protection - the basic backbone of Tribology.
Exactly.
Put some 0W-8 in your engine that's speced for xW-30 or xW-40 and see how mechanically healthy it is at 200K miles.
Ford finally bumped the recommended/speced viscosity for the Coyote from 5W-20 to 5W-30, like it should have been from the beginning. The increase in viscosity wasn't because of CAFE, lol.
I thought we had some clown on this site doing just that or I could just be wrong.
Someone here ran some 0W-5 racing oil in a high HP V8 and the UOAs (and I believe some filter debris inspection) on a short OCI showed it.
Yea I thought we had someone claiming the benefits.
The guy in the video doesn't realize that engines specifying 8 and 16 grade oils have special design features to use that oil. That oil in not meant to use in any other engines besides the ones that have been designed for them. That's why they have their own ILSAC GF designation and logo on the oil bottles. And yes, you can go thicker than that on those engines if you wanted to. It's safe to go up in viscosity, not so safe to do down in viscosity.
What about my post suggested using an engine oil that is thinner than what the manufacturer calls for? The point was that when used in engines that call for it, those oils are very likely not causing issues.
Sure. No argument there. But then my question becomes "Will the average owner of an average car see a real-world difference in how the engine performs over a long period of time."
Yes, a thicker oil provides better protection. This is a demonstrated fact and like you said, the basic backbone of tribology. But over 100-200k miles, with decent ocis, will it matter to the average user? Will the difference in wear rates be enough to be seen?
That's where my post was coming from. It's not people like us. We're the 1% of the driving population that care enough to even do minor research, even if we end up using the same oil anyhow. It's everyone else. I don't think your average driver that drives an average car would notice.
Never a good idea to go thinner than what's recommended - except for the W grade. Sometimes people go thinner on the hot grade, but that could be causing increased wear - see post 50 for an extreme example. Going higher on the hot grade, isn't a problem. Going lower on the hot grade could increase wear, or cause real problems if really too thin under hard use conditions like extreme towing or track use.
Like said earlier, "causing issues" is not the same as increasing wear, unless the increased wear is cumulative enough that the engine isn't as healthy at 150K+ miles (lower compression, excessive clearances, more oil use, etc) than it would have been with less cumulative wear. Lots of people think their engine is in "good shape" as long as it runs on all cylinders and doesn't burn much oil. Doesn't mean it may have some added wear going on. I've seen lots of pretty worn out engines still seem to "run good" while driving them around.
As discussed in every TvsT thread, the use condition of the vehicle is a factor in using the appropriate viscosity for added wear protection. Even Toyota OMs in the USA say to use a higher viscosity if using the vehicle under more demanding conditions. I'd always use a xW-30 in any vehicle calling out xW-20 for the added wear protection headroom, even for normal street driving. If I had a vehicle that speced 0W-8 or 0W-16, I'd also go a grade up on those too. More MOFT between moving parts due to more viscosity equals more wear protection.
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You'd have to do a very controlled test study to know, and you'd have to define what the "average driver that drives an average car" is for the controlled test. If someone isn't doing much except just cruising around at relatively low RPM and load, then the recommended viscosity (basically talking about xW-20 and below) will most likely be fine. Still might increase wear slightly over time, but certainly wouldn't cause the engine to "fail" and "blow-up" as some may falsely "interpret" in these discussions. The slight increased wear as the moles pile up may or may not be noticeable from behind the wheel.
The simple way I ensure to have more wear protection is easy to do, I use xW-30 in engines speced for xW-20. In engines that spec xW-30 I'd only go up a grade if using it really hard or tracking the car. Going up a grade for added protection depending on the use situations is easy to do.
Many wear studies under controlled test conditions conclude that wear on some engine components (piston rings and journal bearings don't like too low HTHS viscosity) start showing increased wear when the HTHS viscosity is right near and below that of a typical 20 hot grade. xW-20 can be right on the boarderline of fully adequate MOFT protection for all conditions. As mentioned earlier, engines that spec the 8 and 16 hot grade have special design aspects (like wider journal bearings and special materials and coatings, etc) to use those very low viscositys.
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He speaks in absolutes with no substance.
The engine won’t make 80K miles. There is no viscosity to 16. The engine is beating itself to death. 30 gives the engine more power. And so on.
Just a bunch of conjecture. And he almost whines as he does it which makes it even more annoying.
The engine won’t make 80K miles. There is no viscosity to 16. The engine is beating itself to death. 30 gives the engine more power. And so on.
Just a bunch of conjecture. And he almost whines as he does it which makes it even more annoying.
4WD
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I have two and they don’t consume oil …
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Seems LSJ is (also) not a fan of Toyota’s ULV motor oils …
Honestly - I’d probably try 0W20 in them …
Honestly - I’d probably try 0W20 in them …
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