Engine oil

[A250 Bennyboy]

Hi all
Just looked up what oil I need on the sticky at top of page very useful thread
The oil for topping my A Class A250 w176 is 5W30 and 5W40 viscosity, is the 5W30 for colder climate like the uk and the thicker viscosity for warmer climate?
Think I'll have to give MB a ring find out what they have put in my car? As I would imagine two different viscosity together is not a good idea
Mine also comes up on the chart engine number 270
Oil chart with two one at 229.3 and 229.5 ?
Both say the same oil viscosity though.

 

[Fendttrisix]

Hi all Just looked up what oil I need on the sticky at top of page very useful thread The oil for topping my A Class A250 w176 is 5W30 and 5W40 viscosity, is the 5W30 for colder climate like the uk and the thicker viscosity for warmer climate? Think I'll have to give MB a ring find out what they have put in my car? As I would imagine two different viscosity together is not a good idea Mine also comes up on the chart engine number 270 Oil chart with two one at 229.3 and 229.5 ? Both say the same oil viscosity though.

You are correct. Mixing viscosity when only topping oil level up won,t affect oil quality or performance. You should be looking more closely at the quality spec of the oil though. There are E numbers and S and C letters eg. SJ and CG the letter S is for Spark ignition engines(petrol) And the C is for Compression ignition engines (Diesel) . The higher the letter that follows them signify the quality of the oil. The E is another quality mark eg. E7 is better quality than E6 and more suitable to Modern engines with DPFs.

 

[190]

It will be fine to top up with either viscosity grade. It's not really about climate as they are both 5W meaning they will have a similar viscosity when cold. The 5W40 will be a little thicker when hot.

229.5 is the newer and better spec and it would be the one I'd look for. If the oil is approved to 229.5 you need not worry about any other quality designations. In an emergency where Mercedes approved oil is not available then the minimum quality to look for is the European specification Acea A3/B4. Both 229.3 and 229.5 must meet Acea A3/B4 as part of Mercedes detail requirements.

 

[MarkII]

Providing you are using a fully synthetic oil with the correct MB approval such as 229.51 then either 5W30 or 5W40 would be fine.

With a multigrade oil the W relates to the viscosity (thickness) of the oil during cold cranking so both the examples you give have the same viscosity and in relation to their performance in the UK are more than adequate for the range of winter temperatures we experience.

The 30/40 element reflects the viscosity of the oil when the engine is at operating temperature (so nothing to do with climatic conditions) - 40 being a thicker oil that will provide slightly more protection under extreme operating conditions and therefore often used in high performance applications.

Of course there's no harm in using the higher grade or mixing grades during top-up (provided the oil meets the same MB spec) but 5W30 is suitable for your engine.

Add: Apologies - the length of my post looks I've repeated some of what's already been said....

 

[A250 Bennyboy]

Thank you all for your information, wow its a bit mind boggling, thanks for explaining the 30/40
MB said castrol edge 5W30 is what they recommend for topping my car up
Once again thanks for all the replys much appreciated

 

[MarkII]

Thank you all for your information, wow its a bit mind boggling, thanks for explaining the 30/40
MB said castrol edge 5W30 is what they recommend for topping my car up
Once again thanks for all the replys much appreciated

Happy to help