0w 40 oil??

[HiddenHOBO]

was just wondering is 0w 40 best to use as this was mentioned to me by a friend at a garage, or shud i stick to 0w 30/ 5w 30 that has been put in before. cnt remember which to use. cheers guys,

[Livi]

Mobil 1 5w-30 ESP is recommended for MINI

[HiddenHOBO]

cheers thanks for the heads up before my car ends up broke.

[GCA3N]

Won't go far wrong with 0W 40 though, fully synthetic oil, mobil 1 normally.

OK found this.

In short, if you see an expression such as 10W-40, the oil is a multigrade which simply means that the oil falls into 2 viscosity grades, in this case 10W and 40.

This is made possible by the inclusion of a polymer, a component which slows down the rate of thinning as the oil warms up and slows down the rate of thickening as the oil cools down.

Multigrades were first developed some 50 years ago to avoid the routine of using a thinner oil in winter and a thicker oil in summer.

For a 10w-40 to attain the specification target a 10W (W = Winter please note!) the oil must have a certain maximum viscosity at low temperature. The actual viscosity and the temperature vary with the viscosity grade but in all cases the lower the number, the thinner the oil. For example a 5W oil is thinner than a 10W oil at temperatures encountered in UK winter conditions.

This is important because a thinner oil will circulate faster on cold start, affording better engine protection and therefore lower long term wear!

For a 10w-40 to attain the other specification target a “40” oil must fall within certain limits at 100 degC. In this case the temperature target does not vary with the viscosity grade, if there is no "W" the measuring temperature is always 100degC.
Again the lower the number the thinner the oil, a “30” oil is thinner than a “40” oil at 100 degC, which is typical of maximum bulk oil temperatures in an operating engine.

Engine makers are, of course, very well aware of this and specify oils according to engine design features, oil pump capacities, manufacturing tolerances, ambient temperature conditions etc. It is important to follow these guidelines, they are important and are stipulated for good reasons.

Finally, if the engine has been modified or is used in stressed conditions, the operating conditions may well be outside the original design envelope. The stress on the oil caused by increased maximum revs, power output and temperature may require that an oil of a different type and viscosity grade would be required.

These examples show viscosities at different temperatures:

Grade................0degC............10degC...... .........40degC...............100degC

0w-40...............665cst.............354cst........ ..........82cst................14cst
5w-40...............842cst............ 430cst..................91cst................14cst
10w-40.............874cst.............440cst .................91cst................14cst
15w-40...........1260cst.............595cst........... ......107cst................14cst

In a nutshell, that’s what a multigrade is all about!

Guy & the Opieoils.co.uk Team

[Gismo]

Yep, what Greig said :Whistle:

[Crombers]

Yep, what Greig said :Whistle:

I got bored after line 3 :yawn:

As for 'oil' ...................... I bought the Castrol stuff that MINI recommend ............. job done :yes nod:

[GCA3N]

I got bored after line 3 :yawn:

As for 'oil' ...................... I bought the Castrol stuff that MINI recommend ............. job done :yes nod:

it's for grown ups, i'll post up noddy does motor oil just for you.

[Crombers]

it's for grown ups, i'll post up noddy does motor oil just for you.

Right you are :babypram:




:Whistle:

[C.Noble]

The whole oil grade labelling thing is proof that the americans should not be trusted with such things!!!!

How is this for a simpler explanation...

10W40

This oil will have a cold viscosity of "10" but when it gets hot, because of these polymers limiting the "thinning" of the oil, it will be no thinner than a "40" grade oil would be when IT got hot...

A 10W30 will be the same viscosity as the 10W40 when cold, but because it has less polymers added, when it is hot, it thins to the viscosity of a 30 weight oil when it is heated... therefore both the 10W40 and the 10W30 will have the same performance when cold, but the latter will be thinner when hot.

As a rule of thumb the bigger the differance between the two numbers, the more polymers in the oil and this shortens the effective life of the oil.

I used to hate training this subject, the whole system is totally overcomplicated... add to that, alot "0" weight oils are exactly the same viscosity when cold as "5" weight... go figure!

[GCA3N]

The whole oil grade labelling thing is proof that the americans should not be trusted with such things!!!!

How is this for a simpler explanation...

10W40

This oil will have a cold viscosity of "10" but when it gets hot, because of these polymers limiting the "thinning" of the oil, it will be no thinner than a "40" grade oil would be when IT got hot...

A 10W30 will be the same viscosity as the 10W40 when cold, but because it has less polymers added, when it is hot, it thins to the viscosity of a 30 weight oil when it is heated... therefore both the 10W40 and the 10W30 will have the same performance when cold, but the latter will be thinner when hot.

As a rule of thumb the bigger the differance between the two numbers, the more polymers in the oil and this shortens the effective life of the oil.

I used to hate training this subject, the whole system is totally overcomplicated... add to that, alot "0" weight oils are exactly the same viscosity when cold as "5" weight... go figure!


Yeh defo easier to read. Like I said originally I have always used a 0W 40 when doing it myself. However a mechanic once told me the best stuff to use was comma 5w 40.