Help

[camcap]

been to look at a 1994 gt4 today everything looks mint goes well theres just this 1 problem if it is one at all we was sat in the car and he turned the car on and a loud huming noise started sounded like it was coming from the engine almost like a buzzing sound he said it was the charge cooler the pump is fine pulling the coolant round and there is no faluts showing on the engine management any help ????