Use the system cleaner in my Ford S-Max 2.0 TDCI. At about 120.000 the engine was running partly somewhat choppy and nailed strongly during cold starts. Thought the injectors give up the service a Diesel System Cleaner has been added. Already there you could tell the difference. So immediately the LM 5128 ordered. Comes since purely about every 5000km. Result: engine runs silky smooth, very much quieter and smoother, feels like a brand new motor. Fuel savings I can not confirm because very often charged different, hard to say. Nevertheless: Top Product, the likes of Diesel engine :)