The hydraulic oil radiator can be refitted, but generally, we do not recommend that you modify the oil radiator.
The excavator has been designed and installed the cooling system, including oil radiator to meet the requirements of normally used.
If you have to add the radiator, you need to take the effect of the pressure drop on the performance into consideration. Meanwhile, the space of extra radiator occupied needs carefully arranged.
If the high temperature phenomenon in the system, there are two general situations that explain it. One hand is a persistent overflow in the system, on the other hand, the radiator does not give full play to the heat dissipation performance. (message from Leo)