Petrol and diesel engines build up carbon deposits inside the cylinders over a period of time. This carbon build up happens for various reasons – from improper burning of fuel, to substandard fuel quality and general build up with age. It deposits itself as soot around exhaust valves, in the exhaust, on the cylinder head, on the piston and on the intake and exhaust manifold.

Over a period of time, especially in older cars, this carbon build up can lead to valves not closing properly, spark plugs fouling, exhaust sensors failing and other issues. Some of the first symptoms of carbon build up will include a lack of power and low mileage from the car. Severe cases will also show up as black soot deposits spilling out of the exhaust.

Chemical decarbonisation involves running a chemical compound along with the fuel through the engine to breakdown carbon deposits. This then gets flushed out along with the exhaust gases. There are a couple of ways in which this is done. One way is to add the chemical along with some fuel in a separate unit that is connected to the fuel intake line on the car. The engine is started and the car is allowed to run for 15-20 minutes or until the mixture is fully utilized. This applies to both petrol and diesel engines.

This method of decarbonizing the engine is alright only as a preventive maintenance routine. Doing this every 50,000km or so will prevent carbon build up in the engine and keep it clean, increasing its life

For engines that have severe carbon build up, a chemical decarbonisation won’t be quite effective. In this case, one will need to do a physical decarbonisation procedure. This involves opening up the cylinder head, removing the intake and exhaust valves and physically “scrapping” the carbon deposits off the valves, cylinder head and manifolds. The exhaust pipe will also need to be dismantled and cleaned thoroughly using high-pressure water. If the exhaust muffler is clogged with carbon deposits, sometimes it will need to be heated and tapped out, before flushing with water.

This decarbonisation procedure is expensive as it involves higher labor costs. Such a procedure could cost anywhere between Rs. 5000 depending on the car brand and the workshop

Old carburetor driven cars as well as older diesel engines was to decarbonize the engine using a fine water mist. This involved removing the air filter and spraying a fine mist of water using a household spray bottle over the intake while the engine was running and being revved. The water would form aas it can ruin an engine if done improperly – leading the engine to seize up! We don’t recommend this process ideally.

which are added directly to the tank have some role in cleaning out carbon deposits (they also help in avoiding carbon buildup). These are way cheaper than decarbonising using a machine

The largest part of most combustion gas is nitrogen (N2), water vapor (H2O) (except with pure-carbon fuels), and carbon dioxide (CO2) (except for fuels without carbon); these are not toxic or noxious (although carbon dioxide is a greenhouse gas that contributes to global warming). A relatively small part of combustion gas is undesirable, noxious, or toxic substances, such as carbon monoxide (CO) from incomplete combustion, hydrocarbons (properly indicated as CxHy, but typically shown simply as "HC" on emissions-test slips) from unburnt fuel, nitrogen oxides (NOx) from excessive combustion temperatures, and particulate matter (mostly soot).

Carbon monoxide poisoning typically occurs from breathing in carbon monoxide (CO) at excessive levels. Symptoms are often described as "flu-like" and commonly include headache, dizziness, weakness, vomiting, chest pain, and confusion. Large exposures can result in loss of consciousness, arrhythmias, seizures, or death. The classically described "cherry red skin" rarely occurs. Long term complications may include feeling tired, trouble with memory, and movement problems. In those exposed to smoke, cyanide toxicity should also be considered.

Carbon monoxide poisoning can occur accidentally or as an attempt to end one's life. CO is a colorless and odorless gas which is initially non-irritating. It is produced during incomplete burning of organic matter. This can occur from motor vehicles, heaters, or cooking equipment that run on carbon-based fuels. It can also occur from exposure to methylene chloride. Carbon monoxide primarily causes adverse effects by combining with hemoglobin to form carboxyhemoglobin (HbCO) preventing the blood from carrying oxygen. Additionally, myoglobin and mitochondrial cytochrome oxidase are affected. Diagnosis is based on a HbCO level of more than 3% among nonsmokers and more than 10% among smokers.

Mono-nitrogen oxides NO and NO2 (NOx)(whether produced this way or naturally by lightning) react with ammonia, moisture, and other compounds to form nitric acid vapor and related particles. It is Emitted th

Small particles can penetrate deeply into sensitive lung tissue and damage it, causing premature death in extreme cases. Inhalation of NO species increases the risk of lung cancer[9] and colorectal cancer. and inhalation of such particles may cause or worsen respiratory diseases such as emphysema and bronchitis and heart disease.

Oil sludge or black sludge is a solid or gel in motor oil caused by the oil gelling or solidifying, usually at temperatures higher than 100 degrees Celsius. Oil sludge can be a major contributor to internal combustion engine problems, and can require the engine to be replaced, if the damage is severe.sludge is basically a dirty, sticky, grease-like substance, formed due to oxidation/contamination of oil in the engine. ... He highlights four main causes of engine sludge. Neglect of maintenance. The main one is delayed service, which makes engine oil to run for more miles than intended.

Sludge is usually caused by a poorly designed or defective crankcase ventilation system, low engine operating temperatures, the presence of water in the oil or crankshaft-induced cavitation, and can accumulate with use. Oil sludge that causes an engine to run poorly or even seize is a rare occurrence and typically happens only when oil changes have been neglected or if the car has been driven extensively with an extremely low oil level.