What is BG 109 and why do you need to flush the fuel system?

Additive BG 109 is a professional fuel system cleaner designed to remove deposits from injectors, carburetors, fuel lines and combustion chamber. The composition works with both gasoline and diesel engines, but has key differences in application. The main active ingredient is polyetheramine (PEA), which dissolves carbon deposits without harming rubber and plastic parts.

Why is flushing necessary? Over time, the system forms varnish deposits, carbon deposits on valves and clogged injectors. This leads to:

  • 🔥 Increased fuel consumption (up to +15%)
  • 🚗 Jerks and failures during acceleration
  • 🔊 Engine detonation and tripling
  • 💨 Increased exhaust toxicity (diagnostic failures)

BG 109 differs from analogues (such as Liqui Moly or Wynns) in that it not only dissolves deposits, but removes them through the exhaust system. However, if used incorrectly, it can clog the fuel filter or damage the catalyst — more about this in the “Typical errors” section.

📊 How often do you flush the fuel system?
Once every 10,000 km
Once every 20,000 km
Only for symptoms of contamination
Never washed

Composition and technical characteristics of BG 109

Official manufacturer data (BG Products, Inc., USA) indicate the following composition:

Component Purpose Concentration, %
Polyetheramine (PEA) Dissolution of solid deposits 40-50%
Hydrocarbon based solvents Removing varnish films 25-30%
Detergent additives Cleaning the combustion chamber 10-15%
Corrosion inhibitors Protection of metal surfaces 5-10%

Key parameters of the tool:

  • 🔹 Density: 0.85 g/cm³ at +20°C
  • 🔹 Flash point: +65°C (safe for fuel tank)
  • 🔹 pH balance: 7.2–7.8 (neutral, not aggressive to sealants)
  • 🔹 Compatibility: all types of gasoline (including E10), diesel, biofuel

Important: BG 109 not compatible with systems GDI (direct injection) some models Mazda Skyactiv and Toyota D-4S — preliminary consultation with the service center is required. It is also not recommended to use with gas cylinder equipment (GBO) without adaptation.

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Before purchasing, check the markings on the canister: the original BG 109 has a holographic sticker and a serial number, which can be checked on the manufacturer’s website.

Step-by-step instructions for flushing BG 109

The flushing procedure depends on the type of engine and the degree of contamination. Below is a universal diagram for gasoline a car with an injector (for a diesel engine, the nuances are described in the next section).

1. Preparing the car

  • ⛽ Fill the tank at 10–15 liters (minimum level for additive circulation).
  • 🔧 Check the status fuel filter - if it has not been changed for more than 20,000 km, replace it up to washing.
  • 🚗 Warm up the engine to operating temperature (temperature indicator arrow in the middle position).

2. Dosage and filling

Standard proportion: 1 bottle (355 ml) for 60–75 liters of fuel. For heavily contaminated systems (mileage >150,000 km), the dose may be increased to 2 bottles, but no more!

How to fill:

  1. Shake the bottle for 30 seconds.
  2. Pour the contents into full tank (not into the filler neck!).
  3. Add fuel until the tank is full to ensure even mixing.

Check the fuel level (minimum 10 l)|Replace the fuel filter (if mileage >20,000 km)|Warm the engine to operating temperature|Shake the bottle before use|Pour the additive into the tank BEFORE refueling-->

3. Cleaning process

After filling:

  1. Start the car and let it idle 5–7 minutes.
  2. Drive 20–30 km in aggressive mode (revolutions above 3000, sharp accelerations) - this will increase the circulation of the additive.
  3. Avoid long periods of idling (risk of catalyst overheating).

Critical moment: if after washing it appears white smoke from the exhaust pipe - this is normal (deposits burn out). But if there is smoke black or blue - stop immediately and check the oil (risk of additives getting into the crankcase!).

What to do if the Check Engine light comes on after flushing?

If it catches fire Check Engine with code P0300 (misfire), this may be caused by temporary clogging of the injectors with dissolved deposits. Actions:

1. Drive another 50–100 km in gentle mode.

2. If the error does not clear, check the spark plugs (they may have gotten cleaner).

3. In 10% of cases it is required re-flushing after 500 km (but not earlier!).

Features of flushing diesel engines

For diesels BG 109 is used diluted — 1 bottle per 100 liters of fuel. This is due to:

  • 🛢️ Higher viscosity of diesel fuel (the additive should be evenly distributed).
  • 🔥 High pressure in the Common Rail system (risk of damage to seals due to excess concentration).
  • 💨 The presence of a particulate filter (DPF), which can become clogged with intense burnout of deposits.

Important for diesel engines with DPF:

⚠️ Attention: If your car is equipped with a particulate filter (DPF), BG 109 can be washed only when the filter is less than 50% full. With a larger load, the risk of clogging the exhaust system increases 3 times. Check the DPF condition with a diagnostic scanner before the procedure.

Flushing algorithm for diesel:

  1. Pour the additive into half empty tank (20–30 liters of fuel).
  2. Top up diesel until the tank is full.
  3. Drive by 50–70 km along the highway at speed 90–110 km/h (to warm up the system).
  4. Repeat the procedure after 300–500 km in case of heavy contamination.
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For diesel engines with system AdBlue (for example, Volkswagen TDI, BMW BluePerformance) flushing BG 109 requires mandatory urea level check after the procedure - the cleaner may temporarily increase consumption AdBlue by 10–15%.

Common mistakes and how to avoid them

Even experienced car owners make mistakes when flushing BG 109. Here are the most common:

  1. Exceeding the dosage:

    Consequences: corrosion of rubber seals, additives getting into the oil, clogging of the fuel filter.

    Solution: in case of overdose drain some of the fuel and add clean gasoline/diesel.

  2. Flushing without replacing the fuel filter:

    Risk: loose deposits clog the filter, causing engine starvation.

    Solution: Replace the filter up to washing or immediately after it.

  3. Use on a cold engine:

    At low temperatures, PEA components work 2 times less efficiently.

    Solution: Warm up the engine until 80–90°C before pouring.

Myths about BG 109things you shouldn't believe in:

  • ❌ "Can be poured into oil to clean piston rings" - this is blunder, leading to destruction of the oil film.
  • ❌ “One bottle is enough for 2 rinses” - reducing the concentration makes the procedure useless.
  • ❌ "Suitable for turbine cleaning" - BG 109 does not contain components for removing coke from turbocharger blades.
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If after flushing the engine begins to work worse (speeds fluctuate, popping noises appear), this may be a sign injectors clogged with dissolved deposits. In this case it will help ultrasonic cleaning or repeated washing with a reduced dose (1/2 bottle).

Compatible with different car brands

BG 109 has been tested on most modern engines, but there are nuances for specific brands:

Make/Model Features of application Recommendations
Toyota (series ZZ, AR) Sensitive to PEA additives Use half dose (175 ml per 60 l)
Honda (engines Earth Dreams) Risk of catalytic converter damage Flush only with mileage <100,000 km
Volkswagen (systems FSI/TSI) Requires mandatory DPF check Use with BG 244 (DPF cleaner)
Mitsubishi (engines 4G63, 4G94) Tendency to carbon formation Repeat flushing every 15,000 km

For vehicles with hybrid systems (for example, Toyota Prius, Hyundai Ioniq) flushing BG 109 is permitted, but requires mandatory dosage adaptation:

  • 🔋 For hybrids with a gasoline engine: 1 bottle per 80 liters.
  • ⚡ For plug-in hybrids (PHEV): flush only the gasoline part of the system.

Important for owners BMW and Mercedes-Benz:

⚠️ Attention: In engines with injection system Valvetronic (BMW N43, N53) and CGI (Mercedes M270) flushing BG 109 may cause unstable valve operation due to changes in oil viscosity. Before the procedure, check the oil level and its condition (there should be no signs of liquefaction).

Alternatives to BG 109: comparison with analogues

If BG 109 is not available or does not fit your vehicle, consider alternatives:

Additive Benefits Disadvantages Price (355 ml)
Liqui Moly Jectron Soft action, suitable for GDI Less effective at cleaning heavy deposits ~800 rub.
Wynns Injection Cleaner Good for removing carbon deposits on valves Aggressive to rubber seals ~950 rub.
Redex Fuel System Cleaner Low price, suitable for old carburetors Ineffective for Common Rail ~500 rub.
BG 44K Cleans the combustion chamber and pistons Requires special injection equipment ~2500 rub.

When to choose analogues:

  • 🔧 For old carburetor auto (for example, VAZ 2107, GAZ 3110) will do Redex or Hi-Gear.
  • 💡 For direct injection (GDI/TFSI) better use Liqui Moly GDI Treatment.
  • 🚜 For diesels with DPF optimal BG 244 + BG 109 at half dose.

Economic benefit:

The cost of one bottle of BG 109 is approx. 1200–1500 rubles. For comparison, ultrasonic cleaning of injectors in the service will cost 3000–6000 rubles, and replacing injectors - from 20,000 rubles. Thus, flushing BG 109 pays for itself after the first use, if it is possible to avoid major cleaning.

Frequently asked questions (FAQ)

Is it possible to use BG 109 in a car with HBO?

Yes, but only when running on gasoline. Flushing with gas is ineffective because the additive does not enter the fuel system. Recommended:

  1. Fill BG 109 into the gas tank.
  2. Drive 200–300 km exclusively on gasoline.
  3. After flushing, you can return to gas.

⚠️ Do not mix the additive with gas - this may damage the LPG reducer.

How many times can I wash BG 109?

For prevention - Once every 20,000 km. In case of severe contamination (mileage >150,000 km), a course of 2–3 washes at intervals is allowed 500 km, but not more often. Excessive use leads to:

  • Destruction of the protective layer on the walls of the tank.
  • Increased wear of the fuel pump.
Will BG 109 help with P0171 (lean mixture)?

In 60% of cases - yes, if the error is caused by contamination of injectors. Algorithm of actions:

  1. Rinse the BG 109 system (1 bottle per 60 l).
  2. Drive 100 km in dynamic mode.
  3. Reset the error with the scanner (for example, ELM327).
  4. If the error returns, check mass air flow sensor (MAF) or air leak.

⚠️ If the error is related to lambda probe malfunction, washing will not help - the sensor needs to be replaced.

Can BG 109 be mixed with other additives?

Absolutely not. BG 109 contains PEA which may react with:

  • 🧪 Octane correctors (risk of detonation).
  • 🛢️ Oil system cleaners (emulsion formation).
  • ❄️ Antigels (for diesel - loss of fuel fluidity).

Exception: BG 244 (DPF cleaner) can be used in 500 km after BG 109.

How to store an opened bottle of BG 109?

The additive retains its properties for 2 years subject to the following conditions:

  • 🌡️ Temperature: from +5°C to +35°C.
  • 🔒 Hermetically sealed lid (contact with air oxidizes PEA).
  • 💡 Store in dark place (ultraviolet radiation destroys active components).

⚠️ If the additive becomes cloudy or sediment appears - do not use!