FAQ

Correct procedure: Use JLM Diesel Extreme Cleaner alone, then drive 200 km on the highway at elevated RPMs to force a regeneration. Once the DPF light turns off, switch to JLM Diesel ReGen Plus for regular preventative maintenance. If the DPF is physically blocked by non-combustible ash (not soot), chemical cleaners will not work and a physical cleaning or replacement is required.

This is a common misconception. Catalytic converters convert harmful gases but do not physically filter them, meaning they cannot be cleaned in situ with chemicals. While products like JLM Diesel Extreme Clean or Emissions Reduction Treatment will clean the fuel system and lower tailpipe emissions, a truly blocked or degraded catalytic converter requires mechanical removal, cleaning, or replacement.

The correct and safe application point is directly into the inlet manifold. This allows JLM Diesel Extreme Toolkit to safely dissolve carbon in the EGR valve and intake valves without harming the turbo. Always follow the step-by-step professional guide provided with the toolkit.

Before assuming mechanical turbo failure, consider that variable geometry turbos often stick due to heavy soot and carbon buildup on the turbine vanes. JLM Turbo Cleaner is designed to dissolve this soot and free up stuck vanes. For best results and prevention, use it every 3,000 miles. If the issue persists after treatment, a professional mechanical inspection is recommended.

Yes! JLM DPF Refill Fluid (J02260) is fully compatible with OEM fluids like Powerflex Eolys (83192208040) used in BMW-Mini and PSA engines. It acts as a direct, cost-effective replacement. However, JLM cannot confirm compatibility with certain third-party systems like Satacen 315 or Pirelli FBC — do not use in those specific setups.

No. The GPF Cleaner is specifically formulated for exhaust filter soot and contains only a mild, regular injector cleaner. For GDI engines with carbon buildup, you must use the dedicated JLM GDI Injector Cleaner, which contains specialized high-concentration detergents to dissolve hardened carbon on injector nozzles and inside the combustion chamber.

Oxygen sensors can sometimes be cleaned using brake cleaner, EGR cleaner, or Direct Injection Cleaner aerosol to remove surface carbon. However, carbon build-up on O2 sensors can be extremely persistent. Replacement is often the recommended solution if they remain faulty after cleaning.

Using JLM GDI Injector Cleaner to achieve cleaner combustion chambers may help reduce the likelihood of LSPI, but additives alone cannot fully control or prevent it. LSPI is a complex phenomenon with multiple mechanical and chemical causes. Keeping the engine clean is beneficial but not a guaranteed standalone cure.

No. JLM states clearly that while additives like the Emissions Reduction Treatment improve overall fuel and exhaust system performance to lower tailpipe emissions, they do not physically clean the catalytic converter itself. If your cat is physically degraded, it must be replaced.

It depends on your goal. E10 Fuel Treatment protects from ethanol corrosion, stabilizes old fuel, and adds +1 octane point. Octane Booster adds up to +4 octane points for pure performance gains. If you need fuel stability and protection → E10 Treatment. If you need power → Octane Booster.

Yes, highly recommended. JLM E10 Fuel Treatment stabilizes the fuel and reduces corrosive acid formation, preventing the fuel system from degrading while the vehicle sits in storage. It is ideal for classic cars and motorbikes used infrequently.

JLM Engine Oil Flush is specifically formulated to safely dissolve sludge, varnish, and harmful build-up at a microscopic level rather than breaking it off in dangerous chunks. It safely cleans the engine internals before an oil change, ensuring your fresh oil isn't immediately contaminated by old deposits. It is safe for high-mileage engines.

You have two targeted options:

1. JLM Stop Smoke Oil Treatment — Reduces exhaust smoke, engine wear, and oil consumption while restoring performance.

2. JLM Engine Oil Stop Leak — If oil consumption is caused by worn seals leaking oil into the combustion chamber, this reconditions and seals those worn motor oil leaks.

Noisy hydraulic lifters are typically caused by dirty oil, sludge, or contaminated oil preventing the lifters from pumping up properly. Use JLM Engine Oil Flush right before your next oil change to dissolve the harmful deposits causing the lifters to stick, allowing them to drain out with the old oil.

JLM Engine Oil Stop Leak (J06055) contains the latest seal-swell additive technology that restores the pliability of hardened rubber seals, compensating for wear and stopping minor leaks. It works on petrol, diesel, and hybrid engines.

Initial start-up is the most critical moment for a rebuilt engine. JLM Turbo Pre Lube is a synthetic oil designed to support initial turbo start-up and protect critical components. Additionally, use specialized assembly lubes to coat bearings, camshafts, and cylinder walls before the first oil fill, ensuring no dry friction occurs during those first critical seconds.

JLM BluBoost is excellent at cleaning and preventing crystal formation in the AdBlue dosing system. However, if severe crystallization has already triggered an error, a physical repair or replacement of the affected pump or nozzle is necessary. Use BluBoost after the repair to prevent crystals from forming again.

You likely have an internal flow restriction caused by rust, scale, or degraded coolant blocking the radiator or heater core. Use JLM Radiator Clean & Flush to dissolve rust and iron oxide blockages, restoring proper flow. If the system is sealed but you suspect a micro-leak causing pressure loss, a Cooling System Sealer can patch the leak from the inside.

Additives should only be used for minor seepage or as a temporary stop-gap to get the vehicle to a garage safely.

For standard automatic transmissions, it conditions seals, protects gears and bearings from wear, and provides frictional properties to ensure smooth shifts.

No, it is not a leave-in additive. The process is:

1. Add JLM Automatic Transmission Flush (J07020) to the old ATF
2. Run the engine to circulate
3. Flush out the old ATF together with the flushing fluid
4. Refill with fresh ATF

This removes accumulated sludge, grime, varnish, and wear deposits, increasing the service life of the transmission.

No additive can physically replace worn friction materials. JLM's product conditions seals to stop fluid leaks and alters frictional properties to smooth out shift quality. If your clutch packs are physically worn down to the metal, no fluid additive will fix the mechanical failure — the transmission will require a rebuild.

Whining is often caused by air in the system, degraded fluid, or worn internal seals. JLM's Power Steering Fluid with Conditioners helps extend the life of the system and can quiet down noisy pumps by rejuvenating seals and improving fluid lubricity. If you see red/brown/pink oily puddles under the front of the car, the conditioner can help recondition worn hoses and seals.

Yes. Hybrid engines face unique challenges because the ICE frequently starts and stops at sub-optimal temperatures, leading to fuel degradation and condensation. JLM Petrol Hybrid Treatment (J03195) is specifically developed for hybrid, stop-start, and PHEV vehicles. It stabilizes fuel and protects the fuel system during frequent cold-start cycles.

Yes. The JLM Diesel DPF Cleaning Toolkit allows technicians to clean heavily blocked DPFs on-car without removal. Use the DPF Cleaning & Flush Fluid Pack in combination with the tool to dissolve soot and ash directly through the pressure sensor hole. For heavy-duty trucks and buses, use the Heavy Duty DPF Cleaner.

Always follow the 7-step professional guide provided by JLM for safe on-car cleaning via the pressure sensor or temperature sensor port.

Use JLM Injector and Spark Plug Install Paste. It acts as a lifeline for injectors that would otherwise have to be drilled out if they seize or corrode in the cylinder head. This is essential for modern high-pressure injectors, especially in diesel engines.

JLM strongly advises against combining their specialized cleaners with other brands' additives in the same tank. Different chemical packages (especially those containing high levels of alcohol or harsh solvents) can neutralize the specialized detergents and friction modifiers in JLM's formulas, or potentially cause adverse reactions. Always use JLM products as a standalone treatment.

JLM's formulas are precisely calibrated for specific tank volumes. The correct dose provides the optimal chemical concentration for maximum cleaning efficiency without risk. More is not better — accuracy is better.