Additives and Flushes – does your car really need them?

Additives and Flushes – does your car really need them?

Flushes and Additives both solve specific problems for a car’s engine and are to be used as per the manufacturer’s recommendation. Unless there is an issue identified in the engine / radiator / fuel lines etc., there is no real reason to use additives. Additives are generally recommended for older cars rather than new cars.

What additives do not do:

  • Additives do not increase engine horsepower and performance beyond what the vehicle was originally capable of
  • Additives do not magically increase fuel economy (unless for e.g. they clean a clogged injector and thus improve combustion efficiency)

Most commonly used types of additives and flushes are

  • Fuel additives
  • Engine oil additives
  • Engine flush
  • Coolant/Radiator flush

Petrol additives have the following functions:  

  1. Efficient combustion – Antiknock additives are added to increase the auto-ignition temperature of petrol and thereby prevent premature ignition (knocking).
  2. Reducing emissions – by ensuring complete combustion and thereby reducing Carbon monoxide, NOx and particulate emissions.
  3. Reducing corrosion and remove deposits – a number of products are added to petrol to prevent corrosion and formation of deposits, clean fuel lines and injectors etc.

Diesel Additives have 2 main functions:

  1. Improve cold start performance: by enhancing cetane number for diesel and secondly reduce the temperature at which waxes present in the fuel solidify hence permitting cold starts in winter weather.
  2. Lubricity and cleaning: The natural ability of diesel to act as a lubricant may not always be sufficient to protect high pressure injection pumps and fuel injectors, so, depending upon the fuel composition, lubricity additives may be required. During combustion, soot is produced especially when the engine is cold. This soot collects on fuel injectors causing partial or complete blockage of the injection nozzles. Detergents added to the fuel reduce this possibility and clean the injectors.

Engine Oil Additives are added to the engine oil to improve the viscosity of the oil such that it circulates easier within the engine block which improves its lubricating properties thereby increasing the efficiency of the engine itself.

Once the engine is filled with fresh engine oil, the oil additive is poured into the engine and the engine is cranked to ensure its circulation. After that the additive will last for as long as the life of the oil.

There is no fixed time for using additives. They are to be used primarily based on need. For e.g. If you are experiencing excessive particulate / soot emissions  or if there is loss of power due to clogged injectors, issues in cold start etc.

Engine Oil Flushes are added to the old or used engine oil right before it’s drained out from the engine. The engine is then cranked so that the flush circulates within the system. Afterwards, the oil is drained out along with removing any kind of contaminants and deposits which have accumulated in the engine block.

Sludge build up inside poorly maintained engines could cause poor circulation of oil and reduce its life. Low mileage, black smoke from exhaust, engine overheating, are few of the symptoms that indicate that the engine oil is deteriorating warranting an immediate replacement. Its recommended to add the oil flush just before replacing the engine oil.

Recommended frequency of using engine oil flushes is every 40-50,000 km

Coolant or radiator flushes are used for the same reasons as engine oil flushes – to flush the radiator and remove contamination and build up inside the radiator assembly and the coolant pipelines.

The coolant flush is poured into the radiator via the radiator cap/opening such that it mixes with the existing coolant and is made to flow through the radiator and is drained out by removing a drain nut which is located at the bottom of the radiator. This helps drain out all kinds of deposits that have built up inside the radiator over time.

Coolant flushing would be recommended every 30,000 km in order to maintain the cooling system of the car in good condition.

In conclusion

While we see all of the above products being “pushed” by authorized workshops at each service, our recommendation is to use them only when absolutely necessary. And how would you know if you really need one of these products? If you experience any of the symptoms mentioned in this article we would recommend carrying out an engine health diagnosis for your car to scientifically determine what could be the issue and then use an additive that addresses the specific issue.