Abstract Water-based ternary hybrid nanofluid with various shape nanoparticles, i.e., spherical (Al2O3), cylindrical (CNT), and platelet (Graphene) as a new radiator coolant has been investigated in the present analysis. Effect of thermo-hydraulic (pressure drop and heat transfer rate) performance along with exergetic analysis (irreversibility, entropy generation, exergy loss) on ternary hybrid nanofluid vol. concentrations, coolant flow rate, and frontal air velocity has been considered. Furthermore, the XRD and SEM morphology analysis have been conducted for 1% vol. fraction of ternary hybrid nanofluid. The comparative theoretical analysis revealed that the change in ternary hybrid concentrations play an important role in thermal performance due to its shape configuration and 18.45%, 6.3% increment in the heat transfer rate, the second law of efficiency respectively, are observed for 1%–3% vol. fractions range. The irreversibility of the system increases with the application of ternary hybrid nanofluid on coolant flow rate and frontal air velocity. However, a 42.45% increase in irreversibility is observed for a change in ternary hybrid concentrations within the range of 1%–3%. Change in entropy for air is higher compared to the coolant entropy change and results in an increment of 27.27% in entropy change for ternary hybrid nanofluid. Similarly, an increase in air velocity also has the least effect on fan power. Thus, the particle shape in ternary hybrid nanofluids has a significant impact, and its application is more effective in enhancing the thermo-hydraulic performance for an automotive cooling system.