My car handbook (Verso 1.6D-4D) recommends using diesel with a cetane rating of "48 or higher". Whereas petrol fuels detail their octane rating, I am struggling to find any cetane details for diesel - even fuel manufacturers' websites seem coy on this question. Am I missing something obvious?

All diesel road fuel sold in Europe has to comply with EN 590 standard, which specifies a minimum Cetane Number of 51 and a minimum Cetane Index of 46.

en.wikipedia.org/wiki/EN_590

So your question to Toyota is - does Cetane rating mean Cetane Number or Cetane Index.

Edited by RT on 06/02/2016 at 11:23

As RT says above, all diesel sold from forecourts in the UK should meet EN590 which states a minimum cetane number of 51.

Manufacturers usually mean 'cetane number' rather than 'cetane index' - the manual for my Volvo states 'diesel with a minimum cetane number of 49' for example. In some European countries the cetane number is slightly lower than in the UK.

The oil company's data sheets for their diesel can be found online, which give the full spec of their fuels including cetane, waxing point, pour point and so on.

Shell's data sheets for its standard Fuelsave diesel state that the typical cetane number when tested is 52 to 54. Interestingly, the data sheet for the V-Power diesel give exactly the same data for all parameters, including cetane, ash residue, etc etc.

However, a higher cetane number does not mean a 'better' fuel. The higher the cetane, the easier the fuel ignites and burns faster. This is not always desirable in a modern diesel with multiple injection phases.

Basically, stick to busy forecourts that sell a lot of fuel, and you'll be fine.