As a part of the scheduled maintenance, Engine valve adjustment is required on some engines. Today we have a Mitsubishi Triton with a 4D56 diesel engine. The vehicle had very low power and was rattling. As this was a new client we didn’t have any history on previous maintenance. The valves sound well out of adjustment with an audibly test.
The valve adjustment is an important task. The adjustment is to ensure the correct gap is maintained between the rocker arm and the valve. If not enough gap the valves can be held open, this can also indicate another issue – valve seat recession. If the gap is too big the valve wont be able to open fully as designed. This Triton had approximately 3-4mm gap which opposed to the 0.1mm specified – is extremely loose. This only allowed the valves to partially open causing huge amount of lost power and economy, along with a terrible rattle from the top of the engine.
The engine is required to be cold, so after leaving the vehicle overnight we carried out the valve adjustment. This requires a fair bit of labour on this engine. As the valve cover comes off we replaced the cover gasket at the same time.
After the repair, the performance difference was instantly noticeable and the engine was now running smooth with no rattles.
The video attached shows how loose the rockers were before the adjustment – this is extremely loose!
If you’re on the Gold Coast in Queensland and need a mechanic – contact us today.