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rotella 5w-40 in gas engines

20K views 18 replies 11 participants last post by  Mr_Roboto 
#1 ·
Any reason why not to run the rotella 5w-40 synthetic in a gas engine, even one spec'ed for 5w-20?? 20w oil seems too thin to me in an automotive engine..... I'd like to keep the same oil in all my vehicles.....any thoughts??
 
#2 ·
besides it not being the recomended weight oil I don't see a problem running rotella in a gas engine. My buddy use to work in fleet maint and they ran rotella in everything. As far as the weight you being somewhere so cold I would be worried about it being too thick. If they say to run 5-20 I would run 5-20 especially if it was a new engine. Now if it had 150k I might run a little thicker oil.
 
#3 ·
Actually, I think they specify 5-20 to help fuel economy. What they mean is to not use 10-30 (won't hurt a thing, though) or 15-40.
I used to use Diesel rated oils (Rotella T) in all my vehicles. The additive package is a little different in the Diesel rated oil than what's in the gasser oil. I don't think you'd have a problem because of it, though.
 
#4 ·
Diesel oils have a much higher detergent oil. Meaning that if your motor has any sludge buildup, the diesel oil can cause the sludge to chunk off, clogging the oil pickup screen.

Yes I've seen this happen from that exact scenario.
 
#5 ·
Sludge won't be a problem, only 7k miles on car..... more concerned with proper flow etc. throughout the engine and whether the 40 weight will flow adequately throughout when the engine is hot... when cold theoretically the oil will be the same,(5w)but as the oil temperature rises and the additive package "thickens" the oil, will it flow properly???? any oil experts out there???
 
#6 ·
The viscosity won't be a problem. The oil never gets any "thicker" than it's base weight. It just doen't get a lot "thinner" either. So, it is an oil with a viscosity of 5 at 100F and is equivalent to 40 at 210F. It doesn't thicken up as it gets hotter.
 
#7 ·
There's been a LOT of talk in Hot Rod Magazine, and on "BobistheOILguy" website about using diesel rated oil in gasoline race engines because since almost ALL new car engines use roller cam followers and roller rocker arms they've decreased the amount of Sulfur I think it is in all NEW oils since sliding friction in cams and rockers isn't a problem anymore and race engines with flat tappet cams were wiping lobes off in a very short time. The fix was to use a 15W-40 diesel rated oil suitable for 20 yr old Cummins engines or 30 yr old farm tractor engines like the old FARMALLS.... A good oil like Rotella 5W-40 synthetic would be a great oil for a new Ford car that recommends using a 5W-20 oil in a very hot climate but I wouldn't recommend it for cold temps.
 
#8 ·
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: montanafan</div><div class="ubbcode-body">The viscosity won't be a problem. The oil never gets any "thicker" than it's base weight. It just doen't get a lot "thinner" either. So, it is an oil with a viscosity of 5 at 100F and is equivalent to 40 at 210F. It doesn't thicken up as it gets hotter.
</div></div>

I concur. Oil is thickest when it is cold, an oil with a wider spread just thins out less.

The heavier oil won't hurt anything but fuel mileage. Which is the whole reason for the very light oil. Modern engines are assembled with very tight tolerances, which makes them able to use the lighter oils. Of course as they wear they need a thicker oil but these days a motor will outlast the car for the most part.
 
#9 ·
I don't understand why we should complicate things. Use oil engineered and rated for diesel engines in diesel engines and oil engineered and rated for gasoline engines in gasoline engines....sorry to be trite, but I just don't get it. I have been reading oil posts on this site for years now and have come to believe that you can get so anal about oil that you become obsessed with it. Frankly, I believe if you use good quality name brand oil, with the proper viscosity and certifications, changed at the proper interval, it does not matter in the least which brand you use, how much they advertise, how much it costs, where you can get it. I am beginning to think that folks are buying oil like folks sometimes buy dog food, which has the best looking pup on the package, ingredients be damned..........That said, there has been a long debate about using lower viscosity oils in vehicles as recommended by the manufacturer. There is no question one of the primary reasons for the lower viscosity recommendation by the manufacturer is increased fuel mileage. I used to be in the camp that 20-50 was the only "real" oil. After owning at least six vehicles that require 5-20 or 5-30 and following the recommendations I have weaned myself from that thinking. I have enough trust that the engines are engineered to operate at the recommended viscosity, so far, so good.
 
#10 ·
100% correct.
By the way, I use 20-50 in my lawn tractor. Great stuff.
 
#11 ·
Kingtut, I can tell you from personal experience that different brands of oil can make a huge difference. PSD's are the most sensitive because of their HEUI system that uses the oil as hydraulic fluid, but IDI's can also be affected (primarily useage levels).

I had a wrecker that would literally run out of oil with Brand X, and use a quart a week on Brand Y.

Oil these days IS complex, all the additives are one reason we are no longer scrapping cars at 90K for worn out motors.
 
#12 ·
i know rotella makes my powerstrokes sound alot louder and have alot more clatter than motocraft does. would it be the same in a gasser?
 
#13 ·
Doubtful, but again, why use an oil engineered and developed for diesels in a gasser. One of the previous posts pointed out that there was a difference in brands. I agree. I like to find a high quality oil that can be bought in a discount environment, one that is "here to stay" and stick with it. I use Motorcraft 5-20 syn blend in my 07 Honda Civic, I use Castrol syn blend 5-30 in my 07 GMC Sierra, I use Mobil 1 10-50 in my 93 Mercedes, I use Castrol high mileage 10-30 in my 2003 Pontiac, I use Delvac Super 1300 in my 97 7.3 F-350, and I use Castrol 10-30 in my 94 Accord, I use Kubota brand oil in my tractor and Honda oil in my generators and Honda lawn equipment and 4 wheelers. I use Mobile super clean 7500 synthetic blend 10-30 in my Honda outboards. I use Stihl 2 cycle oil in my lawn and garden products. I use Mercury high performance oil in the foot of my outboards. I use Lawn Boy 2 cycle oil in my oil injected 1991 Lawn boy lawn mower (still runs and cuts like the day I bought it). I think that about covers it, I think. So yes I agree that there are differences between brands and I have carefully chosen them according to my preferences. In over 30 years plus of owning internal combustion engines including diesels, 2 and 4 cycle engines I have yet to experience an oil related failure. But as I have come to realize who knows what the next day will bring. One addition, if I can, depending on the circumstances I always like to use the factory oil filter, just a little thing of mine. If in warranty I ALWAYS use the factory filter, not required, but again just my thing, works for me.
 
#14 ·
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KINGTUT</div><div class="ubbcode-body">Doubtful, but again, why use an oil engineered and developed for diesels in a gasser. </div></div>

But Rotella is designed AND rated for Both gas & diesel engines. A stronger detergent package is going to clean Your engine's insides better whether it's a gasoline/LP fueled engine or a diesel. The only problem I've EVER heard in almost 50 yrs of being around ALL kinds of engines was with International Harvester gasoline engines in the late 50's & early 60's that engine oil additives contributed to valve/combustion chamber deposits which caused valve burning on VERY heavy constant high loads and caused IH to develope "Low Ash" motor oils. Most automotive motor oils now days have this same technology.

Same as You I'm REAL fussy about servicing My vehicles. I use Stihl 2-stroke oil in My Stihl & Echo yard equip., Mobil I of the proper viscosity in the new cars (5W-20 in the Ford, and Volvo in winter & 10W-30 in the Volvo in summer) and either 15W-40 or 10W-30 Rotella in EVERYTHING else which includes the PSD, two Farmall gasoline engines that are both over 50 yrs old, one's never been rebuilt, and about a dozen Kohler one-cylinder air-cooled engines in garden tractors. I just tore one down for a rebuild after over 1400 operating hours according to the S-W hour meter and there's NO ridge at the top of the bore. Yes there's wear on the piston & bore, but even the rod bearing mat'l looked almost good enough to reuse, but I won't.

Neighbor Farmer I worked for during busy seasons back in the late 60's up until about 1980 used the same 30 weight Series III oil in EVERYTHING on His farm from His Wife's car, All His pickups & trucks, all His gas & diesel JD & Case tractors, His Combines, EVERYTHING, and also without any engine failures. Like has been said here so many times....I think it's more important how often You service than necessarily WHAT You service an engine with as LONG as it's properly rated for the engine You put it in. I also always use the oil filter sold by the engine manufacturer. No exceptions.

If I was You I'd find at least one brand and stick with it... Another reason I use Rotella & Mobil I is because I can walk into about half the major merchandizers or gas stations and Buy a gallon or a quart of it! I drove from Ann Arbor, MI. to Chicago one night looking for a quart of 10W-40 Valvoline I could have filled a 18-wheeler with all the Pennzoil I could have bought but No place had Valvoline. I put two quarts in the back seat when I got home at 3 AM and recycled them but didn't remove them finally until We got rid of the car 12 years & 125,000 miles later.
 
#15 ·
The reason is hinted at above. Since the zinc levels have been significantly lowered in gasoline oils, there has been a rash of flat tappet cam failures. Newer vehicles all use roller cams which won't have this problem. Diesel oils have higher levels of zinc, which makes it a safer oil to use with flat tappet cams.
 
#16 ·
I maintain 32 engines on the ranch,everything from lawn mower to quads to pickups gas and diesel to larger tractors.I use delo 15/40 in everything and have no problems.The 2 stroke engines all get husqavarna 2 stroke mix no matter what brand they are.I will use any good quality filter( they all cant make the best for their own brand of vehicle).Dumb luck maybe but I only have 1 brand of oil and im good to go.
 
#17 ·
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: montanafan</div><div class="ubbcode-body"> ... it is an oil with a viscosity of 5 at 100F and is equivalent to 40 at 210F. ... </div></div>

Huh?

http://www.tribology-abc.com/abc/viscosity.htm
 
#18 ·
We had a 1992 Explorer that had started using oil Motorcraft 10-40 by the time it hit the low 100K's and on a whim I used Rotella 15-40 for a change because I had some left over. Was very surprised when at 3K I had not needed to add any oil and it actually completely quit using oil, we traded it at 142K.

Long way of agreeing with the detergent qualities of the current diesel rated oils.
 
#19 ·
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: montanafan</div><div class="ubbcode-body"> So, it is an oil with a viscosity of 5 at 100F and is equivalent to 40 at 210F.
</div></div>

You're getting your celcius and fahrenheit mixed up.

The temps are 0 and 100* C, 32 and 212* F (freezing and boiling points of water).
 
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