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Engine Oil Change- Selenia or any other synthetic

Discussion in 'Technical' started by ysapre, Jun 30, 2010.

  1. Please explain why will an engine have friction when it starts with 5w oil?

    What is your understanding about the differences between a 5w and a w40 oil?
  2. asimpleson

    asimpleson Esperto

    Linea 1.3
    If you want a detailed explanation please read this bit on wiki. This should help you decode any oil viscosity related satements or arguments. 10W is passable on MJD engines for cold start conditions in Pune and Mumbai and other places of hot, humid or semi-arid climates. For that matter anywhere or most of India where freezing temperatures are not common.

    Oil Labelling Explained - TechWiki

  3. I know it very well. Thanks for the links.. I have read these some years ago. Good revision.
    What I was referring to was an assumption from italia-linea. He thinks that an engine designed for w40 oil will have more friction if it uses 5w oil and less friction when it uses 10w oil. When the engine is situated in coastal region which has hot ambient temperature. A 5w40 will be slightly more fluid and free flowing than a 10w40 at any temperature above 20 degrees and much more fluid at temperatures below zero.
    I wanted to get his understanding of the subject before jumping in to clear his assumption.

    Sent from my GT-I9082 using Tapatalk
  4. asimpleson

    asimpleson Esperto

    Linea 1.3
    Yes, I know what your question meant, but cannot be too sure what he meant, he knows better so he may comment about that.
    I just think that there are too many factors related to your question, that if read carefully and understood properly can help lead to more accurate conclusion. More like a self-help to understand, than to ask. Hope you agree. :)

    BTW, there is no W40. There is 0W, 5W, 10W (W stands for winter if you know) or graded thinness of oil in a way. 40, 50, 60 is the graded thickness for summer conditions or more appropriately hot to extreme hot operating conditions as applicable to engine type.

    Also yes, MJD Engine is designed and is safe and healthy at SAE40 or more precisely multigrade 5W40 spec. (tighter tolerances to be taken care of by oil of particular thickness at cold and hot temperatures). Certain high performance or race tuned engines might want thicker 50 or 60 (60 are bike oils generally). Oil grades are recommended by manufacturer after thousands of hrs of engine operating temperatures, testing and considering multiple internal component tolerances, amongst a host of other tests. Multigrade engine oils need to flow and maintain the requisite oil pressures in cold start or first start conditions especially; so the real question we need to ask is, how does one measure if the oil pressures are right as per manufacturer specs. (if provided to layman) and how much at varying engine speeds and temperatures does the oil perform? What oil pressure sensors are there on MJD to begin with? If and how do they log or report the driver of vehicle?

    For many of us in India, anti-freeze oils should assume less importance than a HTHS (high temp high shear) factor no. oil for all practical reasons, unless ofcourse engine oil pressure is not building up in the first place due to totally wrong oil grade. The lower W for Winter no. is important in this scenario to provide better flow and reach the tighter tolerances of various bearings etc. etc.
    5w does have better flow characteristics, but it is rated for better viscosity index for engines in 'real and prolonged winter' conditions. Besides the oil longevity is a different factor due to more levels of refinements and synthesized blends derived from base oils or other bi-products of petroleum. Also, additives are found in all oils, synth and semi-synth and even mineral oils, so that they dont break down earlier than the recommended oil change interval. So pretty much all oils are safe these days unless out of the box viscosity and/or other ratings are not at all right even for baseline engine lubrication. The practical difference between 5w and 10w is not dangerously wide to conk-off an otherwise healthy engine, the price to performance benefits being very compelling for a 10w40 grade oil use. He is right actually for hot climates a 20w40 could work as well, arguably offering lesser protection at cold (not freezing) start conditions. But what other benefits would it offer being even more thicker than a regular 15w40 under normal operating conditions. Just maybe some better protection on a well aged engine (with widened tolerances post friction), I guess. Then again the question of overall engine health post aging and expected fuel efficiency will need to be considered. Obviously there are certain trade-offs here that one needs to understand and acknowledge atleast for one's own benefit.
  5. There are two parts in your reply. I would quote only one and reply to both.

    First, concern about 'No W40' and one should write just 40. You are both right and wrong here. Actually there is no W40 in the SAE specifications. But there is a catch here, let me explain thoroughly.
    Multigrade oils are denoted by XXW-YY representation like 5W-40. This is the correct way to represent oil. Monogrades are represented by SAE YY like SAE 40. But when you are talking about the the YY value in a Multigrade oil, you have two options. write W-YY or just WYY. I prefer writing W40 rather than W-40.
    W-40 is the wording SAE uses widely in the papers it publishes. For example read this paper http://www.infineum.com/Documents/C...SAE Powertrains Fuels and Lubricants-2010.pdf

    Quoting from the paper - "
    Figure 8. Kinematic viscosity (100°C) of commercial SAE 20 and XW-20 engine oils collected over 30 years"

    For denoting Multigrade they used XW-20. I would have used just W20.

    Coming to the second part of the discussion. Does use of 10w40 in place of 5w40 better in hot areas like most part of India?

    The answere is Yes. The logic which @Italia-Linea gave was incorrect that's why I corrected that logic. But here also there is a catch.. :hit

    The above assumption that 10w40 is better than 5w40 in hot areas only holds good when we are considering both the oils to be of the same type like FS, SS or Pure mineral. But, in reality, you would find 5W-40 oil is FullyS and 10W-40 oil is SemiS.

    5W-40 Total quartz 9000, Mobil Delvac 1 and others are much better than 10W40 Castrol magnatec, Total quartz 7000 and other in any place throughout this world, even in the Sahara desert or Alaska. Not because of grade, but by virtue of the base oil quality.
  6. asimpleson

    asimpleson Esperto

    Linea 1.3
    Yes very true what u said. Just one point is that when speaking to the shopowners for those who choose oil for their cars we have to mention 5w40 or 15w40 in entirety. Besides if one says SAE40 or w40 it could become difficult to know precisely what type and grade of oil one is talking about.

    My point actually was that for an oil semi-syth like helix 10w40, the change interval is also less as is the price. Compare that to a higher quality 5w40 running upto 15k kms and priced roughly 2.5 times the semi-synth oil, that too for non-demanding cold conditions. Amazingly IIRC Selenia WR 5w40 recommended by Fiat is itself not fully synthetic. Yes it may be better formulated for mjds, but really there is no black and white evidence for how better it is than shell's for eg.

    I have tried to confirm after reading data about selenia and then decided to go for helix 10w40 for the Linea. Next on list is a helix diesel which is even better I reckon.

    :p heartsent for our mutual benefit .. !
  7. theblack

    theblack Esperto

    Is there better oil out there than MD1 . I've already used MD1 3 times, although i like it i felt like trying another brand this time.

    Sent from my RM-892_im_india_216 using Tapatalk
  8. amit2301

    amit2301 Novizio

    Grande Punto 1.2
    Now, can I put any oil that is 5W-40 instead of SELENIA?
  9. asimpleson

    asimpleson Esperto

    Linea 1.3
    Which car and what is the odo reading and what oil are you using now?

    Yes you can, but buying oil formulated for diesels is better bet.
    1 person likes this.
  10. GirishRaghu

    GirishRaghu Amatore

    MH-15 / MH-04
    Grande Punto 1.3 90 HP

    I was told that switching to fully synthetic, when the car is still within warranty period, would void the warranty on engine. Is this true?

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