QUOTE(kiaforteclub @ Mar 8 2010, 12:00 AM)
avanza and myvi.. both are diff weight & towing loads ok even same engine cannot get same performance lar! i lazy to mention this lor u win u master of oil ok but i suggest u read the whole FORTE manual especially the back part on service & loads on engine what sort of maintenance is needed.
so 40 is correct for Forte and not 30 as according to specs??? pls use 50 for u're car make sure its 20W-50 for your CVVT ok ...
i do NOT own a forte (yet), and i have not seen the manual.........i do not know what spec naza recommends......
but the sae numbers specify viscosity at a standard temperature, and the lower the sae number, the lower the viscosity........the w in the number stands for winter........so you have qw, 5w, 10w, 15w, 20w, 25w.........above 30 there is no w rating, as these oil are NOT designed for cold climates..........modern oils are multigrade, ie designed to be usable in a wide range of temperature........hence the 2 figures........
the lower the sae number the less viscose, and usable at lower temperatures......therefore if kia specified 5w-30, they are obvious specifying the oil for korean use, where they have winters........it will do NOTHING for the heat of kl.........in fact, if one is concerned about the heat of kl, a higher viscosity (ie higher sae number) oild would be better.........
that however has also NOTHING to do with the type of oil (not grade), which we are talking about, ie whether they are mineral (ie natural extracted from petroleum), or synthetic, or in between.......mineral oils needs additives to allow it to have wide range of operating temperature (ie multigrade), and it is these additives that gets burnt and degrades the oil.......synthetics do not need these additives and hence degrade slower......
how often they need changing......well, read this from wiki......
QUOTE
Some vehicle manufacturers may specify which SAE viscosity grade of oil should be used, but different viscosity motor oil may perform better based on the operating environment. Many manufacturers have varying requirements and have designations for motor oil they require to be used. Some quick oil change shops recommended intervals of 5,000 km (3,000 mi) or every 3 months which is not necessary according to many automobile manufacturers. This has led to a campaign by the California EPA against the 3,000 mile myth, promoting vehicle manufacturer's recommendations for oil change intervals over those of the oil change industry.
It is advised by manufacturers to not exceed their time or distance driven on a motor oil change interval. Many modern cars now list somewhat higher intervals for changing of oil and filter
i am not sure if kia/naza specify full synthetics, i doubt.....so for those who intend to do the 5k/3mth change regularly, use mineral.........those who want to do 10k/6mths, maybe use semi synthetic or full synthetic.......
unless you have lots of dough, in which case, go ahead, use syns and change them every 3 months.......it will not do you car much good, but the spent oil certainly is doing the environment a lot of harm.........