Diesel Cetane Rating: What It Is and How to Protect Your Engine This Autumn

The cetane rating measures how easily diesel fuel ignites once it's compressed inside the engine: the higher it is, the faster and cleaner combustion starts. As temperatures drop, a low cetane rating becomes especially noticeable in hard starts, jerky acceleration and smoke at idle. In this article we explain exactly what cetane is, why it matters more in autumn and winter, and how an additive like NF Diesel Boost can raise it by up to 10 points and protect the injection system.

What is the cetane rating and why does it matter?

The cetane rating is to diesel what the octane rating (RON) is to petrol, although it works the other way round: it measures how easily the fuel self-ignites under pressure, without needing a spark. A higher cetane rating means faster, more complete and more even combustion, with less ignition delay.

Standard diesel in the EU has a legal minimum of 51 cetane points, but real-world quality can vary depending on the fuel station and time of year.

How does cetane affect cold starts?

In low temperatures, diesel becomes denser and takes longer to ignite, so an insufficient cetane rating translates directly into harder starts, a rough idle and a puff of white smoke in the first few seconds. A higher cetane rating shortens that ignition delay and helps the engine start more immediately and smoothly, even when cold.

Common diesel problems in autumn and winter

As temperatures drop, diesel engines tend to show more hesitation, jerky acceleration when cold, a rougher idle and more smoke and soot until the engine reaches operating temperature. Part of this comes from how diesel behaves in the cold, but a low cetane rating makes it noticeably worse.

• Slower starts and extra strain on the battery.
• Hesitation and jerking during the first few minutes of driving.
• More smoke and ash, especially when cold.
• Faster wear on the pump and injectors from insufficient fuel lubrication.

What does a cetane booster do, and how does NF Diesel Boost work?

NF Diesel Boost is an additive poured directly into the tank that increases the diesel cetane rating by up to 10 points. A single bottle treats up to 100 litres of fuel — a full tank.

Its benefits include restoring power and improving acceleration, optimising cold starts, reducing engine smoke and ash, and eliminating hesitation and jerking, while also acting as an extra cylinder lubricant. It's compatible with all diesel fuel qualities and types, in both cars and trucks.

Does it protect the injection pump and injectors?

Yes: NF Diesel Boost protects and lubricates the injection pump and injectors, helping to prevent wear on the moving parts of the injection system and delivering smoother, quieter engine operation. It's a non-flammable product, designed for regular use in any diesel engine.

How to use NF Diesel Boost correctly

It's added directly to the tank, ideally right before refuelling so it mixes well with the fresh fuel. Use one full bottle per tank (up to 100 litres), especially as you head into the colder months of the year, when the difference in starting performance is most noticeable.

You can check the full product page, with all technical data and the current price, at NF Diesel Boost, within the octane boosters category at NF Booster Europe.

Frequently asked questions

How many cetane points does NF Diesel Boost add?

NF Diesel Boost increases the diesel cetane rating by up to 10 points, improving combustion quality and making cold starts easier.

How many litres does a bottle of NF Diesel Boost treat?

A bottle of NF Diesel Boost treats up to 100 litres of diesel fuel, roughly a full tank.

Does NF Diesel Boost protect the injection pump and injectors?

Yes, it lubricates and protects the injection pump and injectors, helping prevent wear on the moving parts of the injection system.

Is it compatible with truck diesel engines, or only cars?

NF Diesel Boost is compatible with all diesel fuel qualities and types, in both cars and trucks.

When is the best time to use a cetane booster like this?

It's especially useful heading into autumn and winter, when cold weather makes hard starts, hesitation and excess smoke in diesel engines much more noticeable.