An oily matter

[Bennz]

I have read threads about difference between 5w30 and 5w40.

But I'm confused about two things :

1- is 5w30 thinner ( easier to flow) under pressure than 5w40 ?
2- for MK5 GTI would 5w40 provide less fuel burn and engine noise ( when there is no fault with the engine )?

I'm thinking of an oil change and just need to be clear with difference for above questions.
It more about being educated correctly.

Thanks

[rich83]

The number before the 'w' is the cold viscosity rating. So 5w30 and 5w40 have the same cold protection.

The number after the 'w' is the hot viscosity rating. So at running temperatures 5w30 is thiner, whilst 5w40 has the capacity to run hotter without loosing its lubrication/viscosity.

Basically 5w40 should be used if your GTI is mapped. 5w40 wont alter your fuel burn, but It could help if your car is burning a bit of oil

[Bennz]

Thanks for the answer.
Sorry in my post I meant oil burn not fuel.

So 5w40 offers better protection and lubrication overall for these engines ? Oppose to w30? My car done very low mileage ( 16000miles ) but I rather protect it from early stage with right type of oil and proper changing intervals.

Many use 5w30, one dealer says 5w40 and another says 5w30 . All confusing

I live in a place that temperature all around the year is considered moderate ( coldest 4c hottest 28c) so weather wise both should be suitable.

Does 2.0 T FSI favour any specific brand of oil ? I know some engines work differently with same spec oil but different brands .

[th3_f15t]

I would of thought in the early stages of your engine, as it wears in, you want thinner oil (at operating temperature) and then later in life (about 100,000 miles) switch to 5w-40 oil.

Go for a fully synthetic oil. These don't break down after continual high heat cycles (experienced in forced induction engines). Mineral oil breaks down after so many miles and needs more regular service intervals.

[rich83]

I would stick some 5w40 in. The TFSI engines do run quite hot.

[th3_f15t]

I might switch to 5w-40 at my 90K service then... You've converted me Rich!

[Bennz]

So Rich you recommend to use 5w40 for turbo FSI 2.0 ?  Any brand you can recommend ?

I seen Shell ultra extra 504 but don't know if there is. Castrol long life 5w40?

[rich83]

Lot of folk on here are using Millers Nanodrive 5w40. Mine runs great with it and helps to reduce cam follower wear too. 

[th3_f15t]

Millers looks great, but pricey!

[Bennz]

Can't find millers in New Zealand

[dansmith180]

I currently use Castrol Edge FST 5w40, but will be switching to Millers after reading all the rave reviews on here.

[Bennz]

Is 5w40 only protects better in higher temp or in general has better protection over 5w30?

When I look at the 5w30 and 5w40 oil in room temperature, w30 seems thinner and more fluid than 40. So I expected for w30 to be easier to get around the engine and lubricate quicker. Or maybe it's just the same and to the eye it looks different ??

[dansmith180]

Is 5w40 only protects better in higher temp or in general has better protection over 5w30?

When I look at the 5w30 and 5w40 oil in room temperature, w30 seems thinner and more fluid than 40. So I expected for w30 to be easier to get around the engine and lubricate quicker. Or maybe it's just the same and to the eye it looks different ??

5w30 is thinner at room temp so lubricates a bit better when engine is cold but engines like ours get very hot and quite quickly so 5w40 is better (especially if tuned) because although thicker when cold it keeps it's viscosity and protects better when the engine is hot.

[Bennz]

Thanks, I think beside from viscosity, the lubrication agents and additives play a huge role in protection.

So maybe a 5w30 with high quality chemicals could protect much better than. 5w40 with low quality ingredients in the oil.Am I right ?

Unfortunately I don't have my car owners manual, but what grade is it recommended there?

[dansmith180]

I believe OEM recommendation is 5w30 and like you say a good quality 5w30 will be fine, however a lot of tuned cars run 5w40 as it holds up better when giving it some.