What Causes the Engine to Make Loud Noises When Exceeding 60 mph?

[Douglas]

Here are the specific reasons why the engine makes loud noises when exceeding 60 mph: Engine Mount Deterioration: The abnormal noise caused by rough engine operation due to deteriorated engine mounts. This noise occurs because the fuel injection timing is too early, and the fuel injection advance angle should be readjusted. Engine Misfire: The engine noise follows a certain pattern, accompanied by unstable engine speed and intermittent black smoke emissions. This uneven noise is caused by diesel leakage from the fuel injector, and the injector should be serviced. Engine Knocking: The exhaust pipe produces continuous backfiring sounds during exhaust, along with black smoke and overheating of the exhaust pipe. Starting the engine becomes difficult, and the backfiring sound reduces at low speeds. This abnormal noise is due to excessively delayed fuel injection timing, and the exhaust pipe position should be adjusted promptly.