Diesel In Winter Conditions In South Africa

Essentially, CFPP is the lowest temperature at which diesel fuel will still flow through a filter under specified conditions. The CFPP determines the temperature at which the waxes in the diesel fuel begin to crystallize and form solid particles that can clog the fuel filter. If the fuel becomes too thick or gel-like in cold temperatures, it can cause blockages, reducing or stopping fuel flow through the fuel system and potentially starving the engine of fuel. Diesel will also not atomise in the injectors under these conditions.

During the winter months (April to September), refineries often blend additives into diesel to meet the Cold Filter Plugging Point (CFPP) specification of -4°C as per SANS 342. In colder regions, refineries may target even lower CFPPs, such as -7°C, to ensure reliable engine performance

Due to the closure of many of the refineries in South Africa, most diesel fuel is not refined locally but is supplied into the country as a direct import. This imported diesel fuel, most cases, exceeds the minimum standards required by SANS 342, including the ability of the fuel to perform in low temperature conditions.

However, should you operate in an environment with exceptionally low temperatures, there are several commercial additives available in South Africa to enhance diesel fuel’s cold weather performance:

• Rislone Hy-per Diesel Complete Fuel System Treatment: claims to reduce CFPP by up to 5°C and also improves cetane number, injector cleanliness, and fuel stability.
• Liqui Moly Diesel Flow Fit K: claims to control the growth of paraffin wax crystals, and improve CFPP by up to 10°C, depending on the diesel’s paraffin wax content.
• Dixon CFPP Improver: claims that in laboratory tests, this additive reduced CFPP from -8°C to -29°C, demonstrating its effectiveness in enhancing low-temperature operability.
• Stanadyne Performance Formula: claims to improve CFPP by up to 13°C and also enhance the cetane number, reduce emissions, and provide corrosion protection.

In an emergency, it is possible to dilute the diesel fuel with illuminating paraffin (IP) to improve its low temperature performance. However, extended use of this mixed fuel will result in excessive wear and damage to the engine, as well as contravening the tax legislation in South Africa.