A device for the continuous determination of the damage to at least one system for the post-treatment of exhaust gases of an internal combustion engine, caused by the lubricating oil, the fuel and/or at least one lubricating oil additive and/or fuel additive used, this device comprising means for incorporating a determined quantity of at least one radioactive tracer in the lubricating oil or in the fuel, and, downstream of the engine, a system for the post-treatment of the combustion gases originating from the engine, comprising:
- (i) a detector sensitive to the radiation emitted by the radioactive tracer, installed near the post-treatment system and at some distance therefrom, in order to measure a radiation emitted by the tracer particles that have accumulated in this system and wherein the detector is placed adjacent to the system to allow a continuous measurement of the emitted radiation while the engine is in use;
- (ii) functionally linked to the detector, a programmed computer which can convert the measurements taken by the detector into the degree of damage caused to the post-treatment system by the lubricating oil, the fuel and/or the additives.