Quazacolt, thanks a lot.

However, I'm still in doubt as to whether the 0W - 50 engine-oil (from Mobil for example); is really a very "thin" or a "very-thick" engine-oil? (Because the way Mobil promotes & advertises it, is as if this oil is a very ultra "thin" super-grade engine-oil that can still 100% protect the engine and can also "withstand super high-temperatures" at the same time; which is very ideal for the high-performance/racing type engines as they say... ) They also mentioned that this 0W - 50 performance oil provides maximum fuel-efficiency... (Which seems to  denote an engine-oil that is "thin"...)

But how is the above so-called "super-oil" different from the (much cheaper) 20W - 50 engine-oil grade (that I've always been using)? (Since in Malaysia's climate, the xW number in the front does not matters...?)

---

Added on February 3, 2012, 6:16 pm

Ford-Laser 1600cc (Carburetor) Manual 5-Speed Transmission. (A very durable engine with strong-torque.)

But I'm getting quite bored with this car now, so I have plans to go for a different car soon.

bro, please just ignore the xw value. the later value is 50, 50 means damn f***ing thick, means your engine will be sluggish in thick oil. as someone as explained, would you swim better in pool of sticky thick glue, or in pure clear water? higher number = thicker, lower number = thinner, in other words, 50 is thicker than 40, or 30

advertisement can claim/say WHATEVER they want, and it may or may not be the truth. if you feel like going with advertisements and go with mobil xw50, by all means, go ahead. your money, your call.

just FYI, racing oils like torco, on their full synthetic line up, their oil are as thin as xw20. you put in xw50 i think people would just laugh at you :/
think about it: if your engine performance is bad, and you require to step on the accelerator more to get the speed/power you need, do you think it will be fuel efficient?

TS,
Personally, I dun see much significant difference of u switching over from 15W-40 to 10W-40 grade lubes mainly as explained in earlier posts tat d 1st rating is for winter n not applicable for our hotter climate. If u were to switch from lubes with different maximum viscosity limits (like my familys >20yr ol car previously on 20-50 mineral -> 15-40 semi-syn), then u'll should b able to notice d engine revving easier.

D main reason mechanics dun recommend thin lubes for older cars is coz d engine has suffered higher wear n hear n would require thicker oil for protection. Another common excuse is to prevent/minimize blow-bys since older blocks might have leaking seals allowing thinner oils tat evaporate easier to exit d blocks at d wrong places.

OK, thanks bro for dispatching the "correct" information.

I also reckon that I have not made a mistake by going for this current xW - 40 (thinner) engine-oil grade (from my previous 20W - 50 grade) in the last oil change.

I also change engine-oil "rather frequently" BTW; at every three months. (Because I can't change oil by referring to my mileage meter because it goes up extremely quickly; in just one month, the meter would already have moved up to around 5000+ kilometers; when I have hardly even drove out the car to begin with...; Nobody uses this car except for me, and I always lock-up the only set of keys. )

---

Added on February 3, 2012, 6:46 pm

Thanks for the information & advice.

Yeah, it's true, all the mechanics always recommend the 20W - 50 engine-oil to be used for this old car's engine, but I don't think that this car's engine even need such a thick engine-oil grade... (It does not have oil leaking & white/blue smoke issue problems...)

you will need to fix your speedometer.

also, it really depends on your engine condition. as previous posts also mentioned:

if you use thinner oil and facing higher engine oil drains (again, by right you shouldnt need to top up your oil, or *AT MOST* one time before OCI just to ensure oil levels are at optimal levels)

by optimal means not too much and not too little.

mechanics may or may not know your engine condition well, and would just recommend something safe, so in the event there are leaks/engine oil drip/colorful smokes as you have claimed (1 of the cause being engine oil slipped through the valves and combusted/burnt off which results in smoke that shouldn't be there) it won't be their fault for recommending unsuitable oil grades.

grades aside, full synthetic > semi synthetic > mineral
for such an old car, its recommended to use at most semi synthetic. it is not to say that you cannot use full synthetic, it's just that doing so would be a waste of money as the benefits/performance gain may be minimal as opposed to the price you have to pay. again, if you're rich, that is no problem and you can use w/e oil you damn well wish so.

OK, thanks man.

The very "only" times that white smoke ever does shoot out from my exhaust pipe is when I have sprayed the Carburetor-Cleaner solution into the carburetor's air-intake to clean it up nicely. (I do it once a week whenever I have drove the car out for at least 5 times, otherwise it will be done just once every two weeks...) The white-smoke will then completely disappear after a while.

However, whenever the weather get very cool at-night after a heavy-rain, some white-smoke usually does come out from the exhaust-pipe; but it usually stopped once the engine has fully warmed-up... (I usually wonder what caused it; although I have read that it is normally caused by water-vapors accumulated inside the exhaust pipe.)

BTW, for engine-revving above 3K to around 4K; which engine oil (type/grade) is generally suitable? (Because I always have the fear of revving my engine above 3K due to the fact that I do not think that my Mineral-based engine oil will be resilient enough to handle it...)

i'm using liqui moly semi synthetic xw40 and i floor my pedal time to time revving 6-7k++ red lining on my 12+ years old proton iswara.

on my nissan sentra i also red line the car around 7k rpm with torco semi synthetic xw30, pickup is a ton faster being a year early 2007 japanese make car and using performance centric engine oil.

Wow, you're just like my bro haha... (He also revs his engine past 5K RPM quite often, and he is using 10W - 40 Semi-Synthetic engine oil...)

However, revving the engine is one thing (because it is easy to do it), but whether the engine-oil can handle it or not is another story... (It may break down faster & stop protecting your engine before the next oil change interval...) Which is what I fear...

I would like to rev my engine at-least to 3K+ RPM and still have the confidence that my engine-oil can take it, and it will not break down before time...

For this case, is Semi-Synthetic recommended over Mineral-based oil? (Would you recommend the xW - 30 grade, or is the xW - 40 grade going to offer more protection?)

Thanks.

the performance of my car pre/post OCI isn't much difference. which means, the oil still maintains all its qualities. and i do OCI around 5-6k+ KM depending on my availability as i am using good quality SS oil.

and of course, semi-synthetic is recommended. good full synthetic is just too expensive and is just not worth it (imho)

viscosity grading depends on your car engine specifications/conditions. for my case, despite a complete overhaul bringing my engine to tip top condition with all its gaskets/seals replaced and all 12 valves replaces as well, i still stick with xw40 because my engine specifications requires xw50 oil. better not go too low/high from original specifications to be safe.

that said, you *CAN* give a shot to lower viscosities and so long you do not face oil drain/burnt off oils/smoke issues, you can stick to it despite of your original engine specifications.

another tip is that, *MOST* famous mainstream commercial engine oil (shell/castrol/mobil for example) simply do not offer the protection as well as performance/racing engine oil that are FAR LESS popular. (eg: liqui moly/torco/amsoil/redline/motul) they are of course a lot more expensive than mainstream commercial oil, and at the end of the day, what you pay, is what you get

Interesting...

But there is a saying/tactic (I heard) that using a "cheaper" engine-oil & changing it more frequently (offers your engine a better protection); compared to using a "more expensive" engine oil & leaving it running inside your engine for an extended period of time... (This is because the addictive(s) inside the engine-oil will all break down at the same time regardless of being a Mineral or Fully-Synthetic oil grade...) Which means that the engine-cleansing addictive(s) inside a "fully-synthetic" Shell engine-oil (for example), will break down "earlier" than the engine-oil itself; so after the addictive(s) had "broken-down", the engine-oil will no longer have it's cleaning-properties anymore... (I wonder how true is this...)

Provided the above is really true, then I reckon it would just be a better idea for me to stick to a Mineral grade engine-oil isn't it? (With the exact same engine-cleaning properties) and just change it more frequently that's all (instead of using a more expensive semi-synthetic or fully-synthetic grade).

This is just my little concern/doubt left about going for a more-expensive engine-oil and letting it run inside the engine for longer... (And can the oil-filter also last as long?)
Anyway, if a semi-synthetic engine-oil can indeed provide me with a better protection during high engine revving (3K+ RPM), and will take longer to "deteriorate" (under constant use); then I will still go for it regardless...

BTW, where are those liqui moly/torco/amsoil/redline/motul engines-oils being sold? (I've never came across any of those oil brands in real-life before...)

Thanks a lot for all your information BTW.

Hi guys,
An engine-oil change will be due for my 20 year old car engine soon;

Currently, this old engine is using the Shell 15W - 40 Mineral engine-oil - (without having any white/blue smoke problems at all).

But for this coming engine-oil change, I am planning to go for the Shell 10W - 40 Semi-Synthetic engine-oil; which has a lower-viscosity - (it will be a thinner engine-oil grade for this old engine).

I would like to put a lower-viscosity (thinner-grade) engine-oil into this old engine to improve it's fuel-efficiency & horsepower. (Correct me if I'm wrong.)

However, I do not want to see any white/blue smoke issues pouring out from this engine after filling it with the lower-viscosity engine-oil...

So the thing is, what (the name of the components/parts) can I tell the mechanic to check/change inside this old engine - (that will minimize or eliminate the possibility of the white/blue smoke issue from happening?)
Your information/advice will be highly appreciated.

I reckon it is also not a good idea to let the mechanic open up this old engine to check here & there... I worried later need to end up doing a full-overhaul. (Because now the engine is still running perfectly fine. )
Oh my, I've never been checking my engine oil level at all... (I'll keep it in mind to occasionally check from now on...)
So far, this old engine does not have any oil leaking problems at all, but I reckon I should start the practice of checking the oil level from time to time...

Will the mechanic have to open up the whole engine to check the "oil seal & gasket"? (Maybe this two components is something I can tell the mechanic to check/replace if necessary...)
But the issue with the 10W - 30 engine-oil grade is that it won't offer so much protection (as the 10W - 40 grade) when the engine (and the weather) gets hotter isn't it? (It will break down faster under higher-temperature & possibly cause sludge build-up isn't it?)
But how come the mechanic (last time) advice me not to go down to 5W - 40 (a thinner oil grade) from my current 15W - 40 (a thicker oil grade), because he told me that the engine oil will start leaking (because it will be too "thin" for my old engine to handle...)

Hence, I don't think the 10W - 40 engine-oil is having the "same" viscosity-level as the 15W - 40 engine-oil (which will naturally still be the thicker oil)...

Correct me if I got it wrong...
Again, I still think that the 10W - 40 engine-oil grade is "thinner" than the 15W - 40 grade. (However, both engine-oil grades will be having the same "resilience-level" at high-temperatures.)

Again, I am worried that the 10W - 30 engine-oil grade will not be as good as the 10W - 40 engine-oil grade in protecting my engine at higher-temperatures (hotter weather & longer idling in traffic-jams etc... as such.) Because it will break down faster than the 10W - 40 grade engine-oil... (I think...)

Now assuming there is a 10W - 60 engine-oil grade, it's viscosity-level will still be exactly the same as the 10W - 40 engine-oil grade, but the 10W - 60 engine-oil grade will be having a significantly higher/better "resilience-level" at higher-temperatures (it will take longer for it to break-down under higher-temperatures - the oil will have a significantly better chance to last longer).

Correct me if I'm wrong. (I hope I am not confused...)

Thanks a lot to you guys BTW.

yes that is true.
however for more expensive/good oils, the concern of having extended OCI periods isnt so much the oil properties or its additives (such as cleansing agents) breaking down, its more towards carbon buildup. no matter how awesome your engine oil is, you will never be able to stop carbon buildup accumulating in your engine, hence some people prefer to just use cheaper oil, or stick to just semi syn instead of going full syn and OCI every 10k km or so.

of course, you can also use good engine oils, semi or full syn, and do 5k km OCI, for that maximum engine protection/performance
there is a reason why in race setups, engines are completely rebuilt every race, using racing grade oil, and what not.

at the end of the day, its up to what you want, and what is your budget.

as for those good oils, you can either look around workshops that carries them (quite rare lol) or even LYN sellers. for instance, gagak84 (not entirely sure on his nick, you can definitely look up automotive garage trade section) carries torco, while thundergod_cid carries liqui moly (and im a frequent customer lol)
the workshop near my house also carries torco, and i buy from them for the nissan sentra OCI

other brands i have not used so won't comment too much on them. nor do i know who sells them/where to buy.

bro, you normally rev not even past 3k rpm, of coz cannot see any white smoke. You should try rev till 5k or 6k and see if really there is no white smoke. Also check your exhaust muffler tip to see is it oily or totally dry with only the black carbon.
10w40 does not have the same viscosity with 15w40, "only when the oil is still not heated up". Once it is heated up to operating temperature, both have the same viscosity. So the foreman that never learn about oil will change viscosity when it is heated up of coz will say the oil is lighter/thicker,they just based it on the oil that came out from the bottle.

Your engine is quite old,some more I believe it's been many years since it is overhauled? There might be places that have gap / hole but it is patched by the sludge from all this time using mineral oil. Changing to semi synthetic and its cleaning agents might cleaned up these sludge and resulted in the oil sipping out from these gap / hole. Unless you prepare to do top overhaul or even full overhaul if this problem do arise, it is not recommended to change to semi or fully synthetic.

On the issue of using lower viscosity oil, ie. xW30. Your engine maybe is designed to run on higher engine temperature, changing to lower viscosity might result in the oil vaporize and also premature shearing, which make the viscosity even lower. And then there the risk of the oil unable to protect the engine efficiently due to lower viscosity. 20 years old engine, I'm sure the recommended viscosity is xW50, you can use xW40 since you also not always high revving the engine, but going for xW30 just seems too low.

blue and white smoke indicate something about ur engine combustion......

i'm not pretty sure bout car engine and i forget what do white smoke indicate but blue smoke cause by an excessive lubricant during engine combustion

whether its cause by thicker or thinner lubricant i'm not sure

u r telling me i'm wrong or giving me the answer?

anyway thanks 4 the link...

im having engine rod knocking noise and foreman say use thicker engine oil will solve that... is that true?