0w-40 vs 5w-40?

elesen

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Hi guys,

I've always used 0w-40 for my car but am now wondering if switching to 5w-40 is ok? From what I googled, it seems like 5w-40 is better than 0w-40. Can sifus explain/elaborate? Thanks!
 

Izso

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If you're talking about the same brand, same type (fully syn vs fully syn) and same additive package - then in Malaysia there's no difference between the two. I doubt you'd be able to feel the difference between the two oils
 

elesen

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Great, thanks! After more googling around, I found that most discussions were centred on running the engine at cold temperatures etc. Thus it isnt applicable in Malaysia then. Thanks Izso!
 

jimmyae101

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what car u drive bro...until u need use very good/expensive engine oil like 0w-40?mobil 5w-40 is enough good for all new car model...but not to proton/perodua... :driver:
 

elesen

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I'm sis, not bro :D Sorry, was a bit misleading as I was actually asking on behalf of a friend. I have some Lexus 5w-40 oil and was asking him if he wants some. He drives a beemer but I'm not sure what model. So what happens if proton/perodua uses 5w-40?
 

jimmyae101

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sorry for my mistake :banghead:.of coz all japanese or germany car model can using fully syn oil as manual book/or service centre also recommed to use it so you can use it if u r ppl who not mind to pay extra for prefect performance.
but no to proton/perodua car model as i know it only can using semi syn oil..maybe it engine not enough good to use that thick oil like 5w-40...as it may cause loss engine oil after few week...yes,my friend have face it b4,perodua kelisa trying to using fully syn mobil 1,of coz his car can move but after few week check back engine level,it loss half tank...check undercarrage,nothing leak.but am guess oil must mix with petrol fuel burn out to exhaust..
leason,engine block,engine piston ring measure gap...
:confused: maybe u get confuse right now? follow manual book ok miss elesen..
 

elesen

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Hehe, gender was not specified, so no problem! I roger you.

Just digressing a bit as I have been wondering, how about rotary engines? I was told that they need to use fully synthetic but what I've always seen is they use GReddy or some oil imported from Japan. Rotary can use 5w-40?
 

6UE5t

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5/40 is thin enough in tropical climates like here. I my self prefer 10/50, or 10/40 or 15/50 but again depends on what car/engine.
0/40 seems a bit too thin especially if you like to rev higher. It's more suitable for cooler climates.
If I remember correctly, it's also better to use oils with less viscosity spread maybe because it should be more stable (cannot remember exactly why/what is the explanation though). Probably later the sifus here can provide better explanation than newbies like me. :)
 

swift2510

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viscosity is viscosity. at the end of the day, it's up to the film strength that counts. going from 0W40 to 5W40 is fine because in our tropical weather we don't have to bother too much about the 0 and 5 visco no.
 

Izso

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Hehe, gender was not specified, so no problem! I roger you.

Just digressing a bit as I have been wondering, how about rotary engines? I was told that they need to use fully synthetic but what I've always seen is they use GReddy or some oil imported from Japan. Rotary can use 5w-40?
OMG.. I think I'm in love :love: A girl who knows her oils and knows what a rotary is!

If you're driving a perodua, using the 5W40 isn't going to destroy anything. The only thing is it'll feel really heavy when you're driving around since the recommended weight is 5W30. Personally, if you have a friend who has a Toyota Vios, Proton Wira, Gen2 or Persona, you can give/sell that 5W40 oil to them. I wouldn't use it on my Perodua. BMWs are very sensitive machines, I wouldn't use anything other than the recommended oil weight the service manual dictates.

As for rotarys, there's a lot of debate going on regarding it. Because the engine is so sensitive to heat, the oil that helps dissapate heat the fastest and prevents build up is the best imho. Most of the rotary kakis I know use mineral 10W30 or 10W40 at most. 5W40 and 5W30 on a rotary shouldn't be a problem but since most of them change oils at 3000km, semi-synthetic or fully synthetic oils are quite pointless.
 

elesen

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Thanks guys.. so although both oils should be ok, it's better to stick to whatever the manual recommends. I don't know which one though but I told my BMW friend that 5W-40 should be ok, based on earlier feedback :biggrin:

Spoke to an ex-rotary kaki today too. He said most are particular about their oils, going for GReddy, Total or Idemitsu. So I think they won't dig Lexus la hahaha
 

Veloc

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Sis? :adore:
 

Izso

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Why did you buy it in the first place? Suggest you open up a buy/sell thread to sell off your oil. Throw in a couple of photos, it'll help.

COD-ing with a girl should help too.. LOL