Why do you want to use other viscosities than those recommended?
From service manual:
"Engine Oil Viscosity
Engine oil viscosity (thickness) has an effect on fuel economy and cold weather operation. Lower viscosity engine oils can provide better fuel economy and cold weather performance; however, higher temperature weather conditions require higher viscosity engine oils for satisfactory lubrication. Using oils of any viscosity other than those viscosities recommended could result in engine damage."
I would stick to 5W30 as the lowest but in tropical heat, yes, glyuen, its me, 10W30 will be better because they have lower VII so the oil holds its grade longer. No harm using 5W30 but don't go speeding up Malaysia with it.
Synthetics only offer high temperature performance. What matters in engine oil is not the basestock alone but also the additives that make up the rest of it. It is these that actually prevent engine wear.
If you are using your car on the drag strip, then synthetics are better for you because your car will experience higher temperatures than most of our street going ones. This resistance to temperature prevents sludging. You don't want to see "coffee grounds" when you drain the sump. That is the only "performance" synthetic oil will give you.
Hi Genie. Din see your reply. Just changed my oil from Schaeffers 9000 to M1 5w30. The engine feels rough and there is slight drop in fuel economy. Any idea for this occurence?
Erm what speeds or rpm can 5w30 take? Constant 130-140 on Malaysia highways fine?
Mine suffered a slight drop also but will be restored later on after 3-4k. I took the same hit too when I used the Citgo but by the second fill, it was at maximum efficiency. The 5W30 should be able to take it.
glyuen wrote:Hi Genie. Din see your reply. Just changed my oil from Schaeffers 9000 to M1 5w30. The engine feels rough and there is slight drop in fuel economy. Any idea for this occurence?
Erm what speeds or rpm can 5w30 take? Constant 130-140 on Malaysia highways fine?
Glyuen, I'm in Australia, I'm using Castrol Magnatec 10w40, and it's purring like a kitten. Takes on doing 120, 130 on freeways. I'd go for something with a higher top-end number; if you really need the lowdown 5, then get 5w40 if you can; keep in mind, the lower the first number, the more expensive. 10w40 Magnatec is like $30AUD per 5L, but for instance, 5w40 is something like $45, if you can get it.