Forum:
I think about engine oil a lot, and maybe a bit too much, but it is a harmless past-time so what the hell. And on reflection I guess it is no bad thing to ponder such a subject because all said and done it is important stuff. Get it wrong and your motor won’t like you for it – maybe not immediately but it will eventually rebel against you.
Anyway, my latest thoughts were prompted by doing a servicing on a friend’s Renault Megane 1.4 petrol (non-turbo) and what surprised me was the quantity of oil it took to refill for the oil change, which was 4.9 litres - there ain’t much left from a full container. In comparison my 1.5 Sirion has a capacity of 3.2 litres, and this made me wonder why my bigger engine had a significantly smaller capacity than the Megane 1.4. My general experience is that larger engines have larger sumps. Of course modern cars and modern oils have shifted that rough guideline but that does not explain this big difference – they theoretically should be similar.
So I figured perhaps the difference would be that the Megane had a longer oil service period and subsequently needed more oil to go the distance and absorb more of those nasty engine bi-products. But no, the recommended oil/filter change intervals are the same at 9000 miles.
So I figured the difference was due to the types of oil and it turns out there is a difference, the Megane recommends a 10w-30 and the Sirion is 5w-30, but does it explain the different sump capacities? I don’t know. I checked a couple of “what oil does my car use” websites to see what they offered as an exercise in curiosity. Mobil came back as the same oil for both vehicles, which was Mobil 1 New Life 0w-40. Castrol came back with 5w-40 for the Megane, and for the Sirion it was 5w-30. It appears the manufacturers and oil companies have some differing views on things, and there was no real insight into why the two sumps were different sizes.
So what of engine vs sump size? Perhaps this difference is explained merely by the Megane being a bit of a lump for a 1.4 litre to push around and it is making the engine (and oil) work harder and more oil is needed to compensate over the same service period. Or is the Daihatsu engine just a much better engine and does more with less. Yes, that must be the answer.
As for service periods for oil and filter I will stick with my own philosophy, which is using 5000 miles as an upper limit. Yes I know oils have gotten better, but my mechanical empathy just won’t let me see the oil turn to burnt toffee before changing it. Seeing the oil golden and fresh is a pleasure for me.
My current oil change regime is Mobil New Life 0w-40 at 5000 miles and filter at 10,000 miles. However last week I decided to alter my oil and filter change to every 3000 miles because the engine has some miles on it now and it gets a good workout so I think it needs the extra care and attention. I have no doubt I am over-servicing but I can tell you for sure the engine knows when it has new oil. I swapped the oil and changed the filter last week at a 3000 mile interval, then went on a fast 600 mile motorway trip and the engine felt very free. Placebo maybe. Or maybe not.
If you know nothing about cars then do what is recommended. If you think about what an engine has to put up with and ponder what engine oil actually does, then make your own decision. Regular oil changes are a lot less trouble than cam chain, cam-shaft, or piston ring replacements.
I did not find an answer to the difference in sump capacities, but I did enjoy thinking about engine oil so I am content.
I wonder if the different
I wonder if the different capacity is driven by the oil's heat capacity - ie more oil will keep a more consistent temperature. Do Daihatsus have an oil cooler? The capacity of my 1.0 Sirion is about 2.2 litres I think, which seems very low.
Or perhaps manufacturers are in cahoots with the oil companies, who will see the benefit of larger oil capacities!
1998 Sirion+
1986 Citroen 2CV
Don't think so. There has to
Don't think so. There has to be a steady state equilibrium. i.e. where the heat is being removed as fast as its being input. Otherwise the engine would overheat and fail.
A bigger sump will take longer to warm up, but once its at a steady state, the average temperature of a big and small sump will be the same (a bit under 100C unless you're racing) though a big sump might smooth peaks out a bit.
Big sump won't get dirty as fast, and you get more time to spot a leak before bad things happen.
Lubricheck Oil Condition Monitoring Gizmo
Thought this was quite interesting, but then I too have become a bit geeky about my oil condition.
Assuming it sort-of-works, I'd guess the marketing problem they still have is that an oil change really isn't THAT expensive, so better-safe-than-sorry is likely to prevail, and therefore most people wouldn't save any money by using one.
http://www.autoblog.com/2013/03/17/nearly-two-years-later-we-get-our-hands-on-lubrichecks-blood/[/url]
http://www.youtube.com/watch?feature=player_embedded&v=eMzKoVFEp2U
The gadget is claimed to measure a combination of dielectric constant and resistance.
Industrial monitoring of oil condition measures a number of parameters, such as pH, TAN (Total Acid Number, by titration against KOH) TBN (Total Base Number, by titration against, IIRC HCl) [I can't get my head around how you can measure those two parameters imdependantly, by titration, but that seems to be the way they are discussed], viscosity, oxidation, particle counts and metallic contaminants/wear metals.
Some of these MIGHT be within DIY scope if one was very keenly geeky, but they aren't trivial to measure.
Changes in these parameters tend roughly to correlate with changes in dielectric constant, so (with many but not all oils) you can allegedly use this as a rough proxy index of oil quality. I've seen some independent peer-reviewed-journal research that seems to support this.
Comment from people who've tried it (or its Oilyzer predecessor) is generally guardedly positive, but some units have been unreliable, its vulnerable to cross contamination if the electrode isn't thoroughly cleaned (I'd probably use alcohol but they don't suggest that AFAIK), and it apparently doesn't work with the additive packages of some oils.
Few punters have "control" data from conventional oil analysis, to compare it to, and it doesn't give direct numerical output of the parameter its measuring, but an LED "quality index".
Its about $40, but I dunno about shipping to Taiwan. I'd consider getting one, though I do wonder if one could make any useful measurements using a multimeter and a suitable electrode
Engine Oil
Edlithgow,
You may have out-geeked me on the engine oil thing, but it is nice to know I am not alone with my obsession. Unfortunately my other passion is gadgets so I am almost overcome. I mean, a gadget that measures oil condition is just too much. Awesome is a very over-used word but I am tempted to say it.
I am strong-willed though and I won't be buying one (although very tempted), and I will just stick to my personal philosophy on oil changes. Thanks for the links to the oil gadget though.
There is one benefit with my Sirion too I forgot to mention and that is I can see the oil filter element, because it is not the cartridge type. When replacing I always take a good look at the dirty element for any bits and all I ever see is just black oil, which is what I should be seeing.
Regards
Geekier than thou
A few more buzz-words for your baboozlement.
(b) Magnetic "Filtration" : ditto, or thereabouts.
(c) Oil Accumulator: To reduce the 90% of wear (or whatever, I've never seen the source for this legendary number) that allegedly occurs due to drystarts.
If I lived somewhere I could communicate with anyone who was likely to have a clue what I was talking about, I'd be quite keen to have a go at making
and (c). Here, getting the plumbing right is likely to be VERY difficult, even if I was prepared to order the gizmo's from overseas.
(b) should be do-able though.