Diesel Exhaust Fluid (DEF) like Adblue® is a urea/water solution injected upstream of the SCR catalyst. Urea decomposes into ammonia (NH3) which serves as reductant in the de-NOx reaction process. However, incomplete decomposition of urea can lead to undesirable deposits formation, which can result into backpressure increase, loss of NOx reduction efficiency, and durability issues. The phenomenon is exacerbated at low temperatures and can lead to restriction or stop of DEF injection below certain exhaust temperatures. This paper focuses on the influence of the additivation of DEF on deposits formation in a passenger car close-coupled SCR on filter Diesel exhaust line installed in a laboratory flow test bench. The behavior of two different additivated DEF was compared to Adblue® in terms of deposits formation on the mixer and SCRF canning at different temperatures comprised between 240°C and 165°C, and different air flows. The influence of the additivation of DEF on the cooling effect of the fluid and the surface temperature of the exhaust line downstream of the injector was also investigated.