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  • Engine oil, educate me!
  • TheFunkyMonkey
    Free Member

    I need to change the oil on our two vehicles.

    Car 1 is an 02 X-Trail, 2.2 DI with the older Nissan engine, 125k miles.
    Last time I did it, about 12 months ago,I used Castrol GTX. I got it free from Tesco with clubcard points! Anyhow, I've not been impressed in the slightest with it. Engine doesn't run any nicer and even seems noisier, bit tappety!

    Manual says 5W-30, is Carlube semi-synthetic any good? I can get that for nowt from a mate.

    The other is my van, PSA 2.2 HDI, citroen relay, 85k miles. Manual says 5W-40 for this.

    Recommendations and experiences welcome,

    Ta

    coffeeking
    Free Member

    Recommendations from me are to get the correct oils for the car (both the multigrade weights and the standards required (small numbers and letters on the back)) rather than anything you can get for cheap/free! It doesn't matter what it costs, providing it covers the basic minimum standards teh manufacturer designed to.

    TheFunkyMonkey
    Free Member

    Have previously and will use the correct weights.

    I was told once that higher mileage engines work better with certain brand oils, sometimes 1 grade thicker also.

    What about these additives, like slick 50 etc?

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    cp
    Full Member

    my view on additives is if the oil was any good in the first place, you wouldn't need additive… possibly of some use in older cars with massive clearances (that need treacle to lubricate them…), though I'm still not sure.

    Anyway, as well as weight, there is often a specification recommended. all the weights are is that – viscosity of the oil at two temperatures when new. Nothing to do with longevity, shear etc…

    the spec, as coffeeking says, is a series of numbers/letters on the back of a can – for instance, ford and vw TDi engines require a very high spec (sometimes referred to as vw spec). i think it's becoming more important in modern (relatively) high performance engines to use the correct spec rather than just the correct viscosity.

    coffeeking
    Free Member

    It's not just the weights you need to look at, there's more to oil than that. You need to look at the API/ACEA grading too, these cover things like the amount of detergents and additives that come in the oil from the factory.

    Ignore aftermarket additives – they're generally just snake-oil.

    Higher mileage engines do sometimes react well to using slightly more viscous oil but primarily because it doesnt burn off quite so easily or seep past the worn seals. From an engineering point of view I'd suggest you use the correct grades because there are other problems you can cause while trying to fix non-existant ones.

    TheFunkyMonkey
    Free Member

    All the premium semi and full synthetic I've seen exceeds the min spec

    coffeeking
    Free Member

    All the premium semi and full synthetic I've seen exceeds the min spec

    That's because it's premium 🙂 Personally I dont bother with semi synth unless I can't find a dino that has the same spec, as a vast percentage of the semi-synths is dino anyway – its very much a marketing gimmick, but sometimes companies only make their dino's to the lower standards so you have to buy semis. Just find the cheapest oil at the right grades and right spec for your engines and throw it in. If you do lots of unpleasant stuff with an engine (lots of cold starts, lots of stop-starting, or a vastly modified engine) you might want to go for an ester-based synth, but they are ~£30 a gallon.

    TheFunkyMonkey
    Free Member

    They're both pretty low mileage vehicles, the X-Trail has only done 12k in the last 2.5 years. Mostly cold starts and 15-30 min journeys.

    Which brands are ester based?

    coffeeking
    Free Member

    15-30 mins is long enough for the engine to warm up, assuming they're not used regularly for towing and dont have any health problems I'd personally stick with whatever you can find that meets the API/ACEA grades required. Ester based oils are very much a sledgehammer-nut situation here. Most of the major manufacturers make ester based fully synths (the ester based types are, apparently, the ones which have polarised molecules which tend to "stick" to engine components better, easing the cold-start lube problems. They also deal with thermal degradation better for cars with serious turbos (think glowing red-hot manifold type applications). On a D you'll clog your oil with soot long before it dies of heat/shearing.

    Just get cheap stuff to the right grades, change it at or before the manufacturers instructions and change the filter every time and you'll be doing all you need to keep it running just fine. Incidentally I found castrol GTX made my celica noisy and burned off rapidly in my first car, I've avoided it since. I now use chevron fully synth (from costco) as it more than matches the grades for my cars and its fairly cheap. Plus you can buy a 20ltr tub of it, which works out well when you have 3 cars all using the same sort of oil.

    kennyNI
    Free Member

    Loads of info from the oilman. Gives discounts to loads of owners club members.

    http://www.opieoils.co.uk/technicalinfo.aspx#oilspec

    uponthedowns
    Free Member

    I do this sort of thing for a living. Coffeeking has it spot on. Find the OEM(vehicle manufacturer), API or ACEA spec recommended for your engine and buy an oil with the correct grade that meets or exceeds the spec required and change it at the manufacturers recommended intervals. If you use biodiesel consider changing your oil more frequently.

    coffeeking
    Free Member

    kenny – what I've regurgitated is the "to the point" version of oilmans comments (he and I have had a fair few discussions on the subject). While his oils are certainly good value for club members (should you be part of an enthusiasts club) they don't really represent oils that you'd buy for a normal car IMO (unless he's changed his ranges since I last looked).

    CHB
    Full Member

    I don't buy into the "old cars need viscous oil" rubbish.
    Its more "worn engines need viscous oil". My car (V40)should use 10w40 and I have been using 0w40 (costco chevron)and more recently 5w30 (Carlube VW fully synth as used in my A2) in it for the last 100,000 miles.
    The car has now done 156,000 miles and uses no more oil than it did when I bought it.
    As said above, regular changes, with filter are the key. I change mine at least once a year. Personally I always use fully synthetic. I accept this might not be stricly needed, but for an extra tenner a year it makes next-to-no difference to my annual running costs.

    coffeeking
    Free Member

    CHB – I'd be mildly concerned about your 5-30 use when you should be on a 40, what you're doing there is running an oil that's less viscous than it should be when up to temp. While it may be within spec (no idea on that car TBH) it might be a bit low a grade. Keep an eye on your hot oil pressure. I stepped to 5-50 when I modified the celica because 10-40 (its normal spec) was getting seriously low oil pressures (despite not flagging a red light) after a bit of hard use.

    CHB
    Full Member

    coffeeking – to be fair I did use 0w40 at the last oil change, but have been topping up with Carlube VW507 spec 5w30 for the last 6 months.
    The V40 has always used a bit of oil, about a litre every 5000miles, but this has remained constant since I bought the car in 2003 with 55,000 miles on it. So by the time of next oil change it will probably be 50:50 mix of oil.
    The other reason for changing oil that is not stated above is that the oil has a cleaning function in that it disolves off deposits and contaminants from the engine. These remain in the oil between changes (hence why it turns black). Obviously if you REALLY abuse your oil it degrades to the point where it begins to polymerise and turn into sticky gunk. Have never even gotten close to this!

    coffeeking
    Free Member

    Eeek, a litre every 5K! Still, remaining constant is sort of comforting 🙂

    kennyNI
    Free Member

    1 litre every 1500 miles here 😀

    coffeeking
    Free Member

    Well my celica gets a full change every 2750 miles (manufactures spec!) but it uses almost none inbetween. My 306 D uses about 1/4 of a litre in 12k miles.

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