I think this is the article from the Ferrari community KingKoopa mentioned:

FerrariChat.com - FAQ: Motor Oil Articles by Dr. Ali E. Haas (AEHaas)

The article makes a lot of sense and helped convince me to switch to 0w-40(Mobil 1) as well and I live in Southern California. It is a long read but has a lot of very helpful information.

 

That's it! Thanks dude, I was having one hell of a time tracking it down. Even though I was certain I had the url saved on my computer.

 

5w40 Mercedes Benz 229.5 spec oil.

Also, I have seen that oil run on AMG's at 220 °on the regular. So for our trucks, I know it can take the heat. 3K changes, Oil and filter.
Jumped off the Rotella Bandwagon months ago, great for the first 2k miles, but starts sounding really buzzy after that. My truck runs fine and I am running the inline mod at 188° on the on some of the hottest days this year so far, if I remember it was 101° outside.

My other car runs Mobil 1 0W40. Will be switching the Rover over to soon.

As far as the oil debate goes(available on every forum that has to deal with anything with an engine), run whatever oil you want. Hell, run unicorn semen if you want to. Its your engine and you are the one that has to either fix it, or pay for to be fixed.
Rover on boys!

 

Hate to do it, but I've gotta agree.

Whether you believe human produced emissions is the cause or not, the cold hard facts are that the global atmospheric temperature is increasing, ocean temps are rising, reefs are dying, polar ice caps are melting, and the ocean level is rising.

Furthermore, and on a smaller level, smog. I don't mean emissions testing; I mean actual smog. Look at Tokyo which has some of the worst smog in the world. Look at the major US cities 20 years ago. Now compare them to major US cities today. Even if you don't believe pollution is an issue on a global level, you can't argue about it being a problem on a local level. It causes cancer, lung disease, heart disease, skin disease, and over time brain damage.

This is coming from a guy that currently has no catalytic converters on his Disco. Soon to change, but I've been on the skeptic side of the fence. The more research I've done the more my mind has been changed.

 

As far as oil is concerned, I buy Rotella 15w40 and 5w40. The 15w40 is too cold for my disco in the winter here; she is not happy on startup. 5w40 is too light year around. I mix them 50/50 for a 10w40 and she's real happy. When I move south to a warmer climate she'll get 15w40 year around.

And as far as brand is concerned (having not read the page you linked), here's my thinking; Go to WalMart and look on the shelves. Look at the number of "Gas Engine" oils that are offered. Now look at the number of "Diesel Engine" oils offered. There are a dozen different "gas" brands each with different lines which advertise different additive packages. On the flip side, there are like three "diesel" oils which only have different weights; not different lines of oil.

That's not because more "gas engine" oil gets sold. There may be more gas powered vehicles on the road, but they drive a lot less miles per vehicle than diesels. The reason is because trucking companies and the like make the investment to do regular oil testing on new and used oil, because that saves them money on parts over time on trucks that drive millions of miles carrying 40 tons behind them. Most regular consumers who own gas powered vehicles don't. That means that trucking companies and diesel owners stick to what works and companies that make poor quality oil simply don't last, where companies that make oil for gas powered vehicles can ride on marketing gimmicks while making terrible oil. I'm looking at you, Quaker State.

ZDDP content be d*mned; diesel oils are tested and proven to be higher quality and they work just fine in gas engines. I also run Rotella 5w40 in my 5.3 LS in my 08 Silverado and she loves it.

Furthermore, it's not just about thickness. It's about flow characteristics and surface tension which are much different in a cup only under atmospheric pressure than they are when they're flowing through a bunch of tiny channels, being crushed by a cylinder firing, and being pumped at 30-70 psi. Heating it up on a stove isn't going to tell you what you need to know for any reason other than temperature based oil break down.

 

"ZDDP content be d*mned; diesel oils are tested and proven to be higher quality and they work just fine in gas engines. I also run Rotella 5w40 in my 5.3 LS in my 08 Silverado and she loves it.

Furthermore, it's not just about thickness. It's about flow characteristics and surface tension which are much different in a cup only under atmospheric pressure than they are when they're flowing through a bunch of tiny channels, being crushed by a cylinder firing, and being pumped at 30-70 psi. Heating it up on a stove isn't going to tell you what you need to know for any reason other than temperature based oil break down."


If you read the article you would know why you are incorrect about diesel oil being superior. Will it hurt your gas engine? Nope. are there better oils for your engine? 100's, literally.

That being said, let's cover the other topic, oil dynamics, which is also covered by the engineer, in much greater detail and with better words lol.

The highest stress points for oil are the crank and rod bearing. Oil needs to be thin enough to flow freely into these tiny spaces, and then stay there in a film and be compressed momentarily. An oils resistance to this compression is its #1 defense against engine wear. The zinc in many of the diesel packages is a last line of defense after the base oil has broken down via heat and oil dilution. Not just average heat in the pan. Oil temp spikes in the high pressure bearing surfaces, so oils that experience thermal breakdown at say 240 degrees don't live very long even though the average sump temp never exceeds that number.

Back to the zinc. All it does is float around and get between what would normally be two dry bearing surfaces because the oil is no longer doing its job. You can see where this would be good for flat tappet engines as there's really not anything to retain an oil film on the cam lobe except for the oil itself. This is where superior oil comes in. It "clings" better, for longer, under higher pressures, and higher heat.

Then you get into detergents and antioxidants, etc, the sub-packages of the overall additive pack. Stuff that a lot of race oil doesn't have because it's changed every weekend.

 

Just curious, I was reading this article (not finished yet) and I was thinking what kind of oil engineer/geek has all these high end cars? I have not yet seen where he tells us what his doctorate was in. Well I looked him up and it makes sense now. He is apparently a very good plastic surgeon...Or maybe I found a different guy with the same exact name?

I wonder how many of us would have jumped off the bandwagon if this was written by Dr. Johnny Fever?

But I digress...

 

I only ran Rottela 15w40 once, maybe twice in my rig. I didn't like the sounds the engine made. I switched to Mobile 1 10w30 and the engine seemed to sound quieter...idk.

 

The first article, the blog, is by a mechanical engineer, I think the second one is just a well informed enthusiast. I think the first guy eluded to his profession but doesn't specify.

Regardless, there are some very stupid engineers and there are very smart job site foreman, and everything in between. I don't need to see someone's doctorate degree before I take their well thought out scientific study seriously.

That's the kind of mentality that has resulted in an entire scientific community that is pigeon-holed into a single ideology, which is completely unwelcoming to any dissenting theories, regardless of how well founded they are.



All that said, if I could find someone that has refuted this guy in a professional and data backed manner, I would gladly read his/her rebuttal and take it seriously.

 

General engine noise is a touchy subject, and If I Remer correctly this guy covers it some. A "buzzy" engine doesnt necessarily mean that it is under protected. However, a 40 weight oil may have very well been too thick for your engine (even engines from the same assembly line can vary in bearing clearances) and resulted in excessive noise, which was an indication of excessive wear. You prob made a good choice.