Process for making an plastic engine cover, comprising the steps of providing an injection moulding installation comprising an injection moulding apparatus and a mould having a cavity shaped in the form of the engine cover; providing a thermoplastic polymeric injection moulding material comprising: (a) a semi-crystalline thermoplastic polyamide polymer comprising (a.i) units derived from dicarboxylic acid comprising at least 75 mole%, relative to the total molar amount of units (a.i), of units derived from terephthalic acid, (a.ii) units derived from diamines comprising at least 20 mole%, relative to the total molar amount of units (a.ii), of units derived from diamino butane, and optionally (a.iii) other units, wherein the other units (a.iii), if present at all, are present in a molar amount of at most 10 mole%, relative to the total molar amount of (a.i), (a.ii) and (a.iii), and (b) at least 20 wt.%, relative to the total weight of the thermoplastic polymeric material, of a glass fibre reinforcing material; melt processing the thermoplastic injection moulding material in the injection moulding installation, injecting the thermoplastic injection moulding material into the cavity, allow the injected thermoplastic injection moulding material to solidify into a solid moulded part and demoulding the solid moulded part from the mould. providing an injection moulding installation comprising an injection moulding apparatus and a mould having a cavity shaped in the form of the engine cover; providing a thermoplastic polymeric injection moulding material comprising: (a) a semi-crystalline thermoplastic polyamide polymer comprising (a.i) units derived from dicarboxylic acid comprising at least 75 mole%, relative to the total molar amount of units (a.i), of units derived from terephthalic acid, (a.ii) units derived from diamines comprising at least 20 mole%, relative to the total molar amount of units (a.ii), of units derived from diamino butane, and optionally (a.iii) other units, wherein the other units (a.iii), if present at all, are present in a molar amount of at most 10 mole%, relative to the total molar amount of (a.i), (a.ii) and (a.iii), and (b) at least 20 wt.%, relative to the total weight of the thermoplastic polymeric material, of a glass fibre reinforcing material; (a) a semi-crystalline thermoplastic polyamide polymer comprising (a.i) units derived from dicarboxylic acid comprising at least 75 mole%, relative to the total molar amount of units (a.i), of units derived from terephthalic acid, (a.ii) units derived from diamines comprising at least 20 mole%, relative to the total molar amount of units (a.ii), of units derived from diamino butane, and optionally (a.iii) other units, wherein the other units (a.iii), if present at all, are present in a molar amount of at most 10 mole%, relative to the total molar amount of (a.i), (a.ii) and (a.iii), and (a.i) units derived from dicarboxylic acid comprising at least 75 mole%, relative to the total molar amount of units (a.i), of units derived from terephthalic acid, (a.ii) units derived from diamines comprising at least 20 mole%, relative to the total molar amount of units (a.ii), of units derived from diamino butane, and optionally (a.iii) other units, wherein the other units (a.iii), if present at all, are present in a molar amount of at most 10 mole%, relative to the total molar amount of (a.i), (a.ii) and (a.iii), and (b) at least 20 wt.%, relative to the total weight of the thermoplastic polymeric material, of a glass fibre reinforcing material; melt processing the thermoplastic injection moulding material in the injection moulding installation, injecting the thermoplastic injection moulding material into the cavity, allow the injected thermoplastic injection moulding material to solidify into a solid moulded part and demoulding the solid moulded part from the mould.