ARTICLE: Synthetic oil vs Mineral oil

[swathyd]

I am using 15w40 for my 1.6 fiat engine is it ok or should i move to 5w50. what will be the benefits by doing so?

[moralfibre]

Swathyd, it is good to move to 5W50 synthetic. If you read through the thread you will be convinced to do so! If your car has done 10k kms then its the right time to upgrate to synthetic and if you have clocked more than that, it doesn't matter you can still opt for synthetic oil in your engine. You will surely notice difference in performance. Two things to ensure while doing this are, ensure that you use an engine flush to drain out mineral oil and change your oil filter.

[swathyd]

Recently while checking shell india site happened to see an oil rated 15w50 what do you think about that ?

[swathyd]

Also read in carbible that palces with hot climate should use w50 rating, and it says oil with 5w rating is needed for countries like canada. So i think 15w50 will do the job here.

[tsk1979]

I was looking up castrol edge synthetic oil.
The oil is rated API-SM/CF, which is a very very high grade for petrol.

But for diesel engines the CF means a very low rating.
Infact using such a low grade oil in modern engines can void your warranty.
So I went in for Castrol GTX diesel which is API-CI a much better rating than the highly expensive synthetic.
From this link:
All About Motor Oil
Look towards the end where it talks about most SM oils being CF standard at most and that CF oil does not meet factory standards of Mercedes or Volkswagon. So For my indica the CF oil will not be a problem, but for others using Castrol edge may be a problem.

Commercial (Diesel) Oil

The additive packages for C (commercial) certification are designed to promote engine life. The additive packages for C rated oils contain extra buffers and detergents to keep the engine clean and free of acids. C rated oils are far better than S oils at holding and dispersing combustion byproducts and other contaminants, and at not becoming acidic. Traditionally these oils are primarily used in diesel motors, which are very expensive and are expected to last a million miles or more. When an engine rebuild costs $10,000 - $15,000 and puts you out of work for a week or three, you don't mind paying a bit more for your oil. The C certification tests have been largely developed by Mack, Caterpillar, Detroit and Cummins to provide the additives necessary to keep these engines running a long time. The latest commercial certification is CI-4 Plus, which includes extra protection for high temperature high revving motors. Since it's designed for diesel motors, they don't care about no stinkin' catalytic thingies, and CAFE is a place where you get a cup of joe and a donut. CI-4 Plus differs from CI-4 with higher detergent requirements and better sheer stability. The shear stability is exactly what motorcycles need due to running the engine oil through the transmission.
Although C standards are changed every few years, the older standards are enhanced, not superceded. So, newer higher rated C oils are simply better than older lower rated oils.
Although few car owners test their oil regularly, most large trucking companies routinely do oil analysis on their diesel trucks. Used oils are checked for viscosity breakdown, for detergent and dispersant function, and for metal contamination that would indicate engine wear. C oils that don't measure up are quickly run off the market place. To prevent engine wear, the best strategy is to keep deposits off the pistons, rings, and bearings. Therefore, diesel oils typically contain half again more detergents, double the dispersants, and a much more expensive and robust VII package than S type oils. If you go to an auto parts store, convenience store, or grocery store, you'll see that there are dozens of brands of automotive oils, all claiming to be the best. If you look at truck stops, you'll see there are only a very few diesel oils sold, typically Rotella, Delo, and Delvac. Trucking companies find what works for them and won't switch. They're not interested in saving a dollar a gallon on some unknown oil.
The C certified oils are all also S certified, just as some S certified oils are also C certified. The best C certified oils are SG, usually SH, sometimes SJ. I don't know of a C certified oil which is SL. The best S certified oils are CF, which is a relatively old and obsolete C standard, and does not include the tests for high speed high temperature engines that CG, CH, and CI have. In fact, CF oil does not meet the current factory standards for Volkswagen or Mercedes diesel passenger cars.
The API charges serious money to test an oil and certify it. If the API really tested the oil in their independent lab, and the oil company pays their royalties on time, the oil company gets to display the API seal on their product. Some smaller companies don't pay the API to test their oils and certify them. In these cases, you won't see the API seal, instead you'll see some words like "Meets or exceeds all manufacturers warranty requirements. API Service SJ, SL, CF." It's up to you to decide if you trust this manufacturer to actually test their oil themselves and tell you the truth about the results.

[kooldude]

Originally Posted by GTO

You got RIPPED! Its anywhere between 500 - 650 a liter in Bombay.



The oil may last 30,000 km but your oil filter wont. I do not recommend using the same oil for more than 10,000 kms in our driving conditions...but if you do (max 15,000 kms) remember to change your oil filter.

hey gto
even i inquired about the rates of mobil 1 at a petrol pump they told me it is 1000 bucks a litre

[tadukuttan]

Originally Posted by tsk1979

I was looking up castrol edge synthetic oil.
The oil is rated API-SM/CF, which is a very very high grade for petrol.

But for diesel engines the CF means a very low rating.
Infact using such a low grade oil in modern engines can void your warranty.
So I went in for Castrol GTX diesel which is API-CI a much better rating than the highly expensive synthetic.

Thanks for this data tsk. Now, did you find, or are you aware of any synthetic oil available in India which meets API-CI specs?

I know Mobil Delvac 1 5W-40 does do API-CI4, but still dont know where to get it.

And I dont get why Diesel Mercs in India use Mobil1 5w-50 which is only API-CF4? And you are saying that CF does not meet Mercedes factory specs (Mercedes Benz 228.5?) for its diesels?

[tsk1979]

Low sulphur diesel engines cannot take API-CF.
The lowest grade the take is API-CG.
Come to Ultra Low sulpher diesels you cannot go below API-CH, one grade above API-CG
If you look at any range from servo/MAK/Castrol etc., you will find that the cheopo commercial oils are API-CD, then you have API-CF/CF-4 which is the GTX magnetic, GTX Diesel etc., etc.,
Shell comes with API-CG.

If you look at any service manual, near the end there is a list of engine oils and minimum specified grade is given.
For modern engines which take LSD, you have to take the newer oils.

The reasons are myrad, including things like phosphorous content in engine oils which can damage EGR and Emission systems.

[nitrous]

Tanveer, The other day i was filling up fuel in a Bharat Petroleum pump and i checked out their oil range. I asked for 15W40 and they had two versions.One for the petrol engines and one for Diesel engines. The Diesel engine oil had a API-CF4 spec and "claimed" oil change interval of 24000 kms.Thats RIDICULOUS!

Btw,What oil do u use and What brand here has CI spec ??

[tsk1979]

On low RPM engines like trucks you can push upto 15000, esp for engines which require API-CD.
I used Castrol GTX diesel which is API-CI, but its rare.
Next best option is Shell, which is API-CG, which I used earlier

I also put in STP diesel engine oil additive which costs 250rs and can be put in upto 5 Ltr oil
I did not use Bhardol because their product says "For engines upto 50,000kms only" and since I am nearing 80K on the indica, I put STP.

After this oil filter and oil change with API-CI oil after using API-CG there is a noticeable improvement in the engine note and performance. The morning clatter has also reduced. Don't know wether its the API-CI oil working its magic or the STP.

Anyways happy hunting for the Castrol GTX diesel. Its not Castrol GTD, thats different.

As for Bharat Petroleum, they have an API-CH and API-CI oil, I saw their web site, but could not find these in their pumps.

The Castrol one costs 640rs for 4 liters, and the GTD costs 600Rs for 4 liters.

[nitrous]

For LPG/CNG users. I found this in BP's website.

"Use of Gas in the Engine will also lead to non lubrication of the inlet valve otherwise lubricated by the liquid fuel particles"
Link:Bharat Petroleum Corporation Limited- Truck Lubricants

[tsk1979]

Nitrous, similar problems for users of LSD and ULSD. Sulphur is a lubricant, so low sulphur diesel has poorer lubricating properties. Newer oils (CH/CI) have better lubrication, and compensate for that.

[nitrous]

So, we can conclude that CH/CI will also help increase engine head life in old gen Diesels.
Hmmm...Im gonna try and source it for my Sumo.

[tadukuttan]

Originally Posted by tsk1979

Nitrous, similar problems for users of LSD and ULSD. Sulphur is a lubricant, so low sulphur diesel has poorer lubricating properties. Newer oils (CH/CI) have better lubrication, and compensate for that.

How do we know what is the kind of Diesel we are getting in India (LSD/ULSD)?

The Elantra's manual specifies only API-CF4, has the Diesel in India changed since then? If it has, has the other manufacturers changed the specs for lubricants required in their cars since then?

[nitrous]

Tadu, I guess the govt. emission regulations would have resulted in LSD or ULSD for all Euro 3 metros.