Shell Rotella T Synth vs Mobil 1

Howdy Dynamoe^Joe,

There are lubes that are better than others but most lubricants will conform to a specification.

In the case of internal combustion engines reference is made of API rating / classification whereby lubricants are rated against specific performance targets based. API also divide the specification into two sub-categories e. g. S and C (S being for petrol / spark ignition and C for diesel or compression ignition). The rating normally consist of two alphabetical characters, the first one indicating the type, either S / C and the second is adjusted in ascending order with the "highest" being the "highest" spec lube.

The highest API lubricant currently available, to my knowledge, is SJ for petrol engines.

Check the back of your can and confirm. Remember that the higher the spec the better the lube (traditional wisdom) but you can be caught in the mode where you are putting very expensive oil into a VERY old machne not requiring the specication but that is another story.

As far as I know the Rotella range has a low specification for petrol engines since it is mainly intended for diesel engines. Personally I would go for the Helix range - MUCH better.

Have fun!

Hello: Kindest thanks for answer.
You mention Helix oil. I travel to Trinidad every once in a while and browse through the speed shops & notice "helix" brand everywhere in that country.

What strikes me as odd [maybe because im from Canada] is the popular use of 20W-50 and 30W-50; the shelves are full of them. Would this be due to the climate? Trinidad is near the equator and temperature range from 25C to 30C and as high as 35C some days.
I would say that nearly 1/2 the cars are diesel compared to gasoline.

I brought back to Canada a bottle of Shell Helix Super 20W-50 and it say on the label...
Combining high-quality base oils with an advanced additive system, Shell Helix Super combats the harmful effects of cold running, stop-start motoring and the formation of black sludge deposits in your engine.

Heh heh, reading "cold running" makes me think of cold starts here in Canada, however im sure the description academically regards to "ambient temperature" for warmer climate.

I have never seen Helix range in Canada however I will ask the distributor of the Ultra model.

Regards
Joey

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The highest API lubricant currently available, to my knowledge, is SJ for petrol engines.

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API SL should be available on the market, the newest Spec from this year is API SM.

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What strikes me as odd [maybe because im from Canada] is the popular use of 20W-50 and 30W-50; the shelves are full of them. Would this be due to the climate?

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Yes, traditionally hot climate countries tend to use such viscosities. Technically there is no need to do so. You should be OK down to -25°C if you stick with a 5W-30 or 5W-40 oil.
The fighting of black sludge is not oil viscosity related.

Strangely all 15-50 or 20-50 oils have disappeared from the shelf of oil dealers in India, some parts of India do get up to 45c average and some even higher at 55c, wonder how good are the 15-40 oils like Delvac, Delo 400 etc then. Paradoxically we also have some of the coldest temp places around where temps on the average dip to -10c average and going to as extreme as -30c so I can see the need for an universal formula here but I would have welcomed the choice of 15-50 for summers and 10-40 for winters.

@ Gurkha
You have to look at the VI (Viscoity index) of an oil. The XW-40 viscosity is valid at 100°C.
It is possible that a 0W-30 oil has at 140°C a higher kinematic viscosity than a 15W-40 oil.
This is important for the summer.
I personally would always use a 0W-X or 5W-X oil in the winter time, it has a much better fuel economy in the warm up phase of the oil.

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Originally posted by Callisa:

It is possible that a 0W-30 oil has at 140°C a higher kinematic viscosity than a 15W-40 oil.

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And perhaps a straight SAE 30 has an even higher yet 140C viscosity?

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And perhaps a straight SAE 30 has an even higher yet 140C viscosity?

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No.