Can you use 10 40 fully synthetic oil in a 1988 ford e350 v8 petrol engine?

No, you should not use 10W-40 fully synthetic oil in a 1988 Ford E350 V8 petrol engine without checking your owner's manual first. While 10W-40 is a common oil weight, older engines, especially those from the late 1980s, often have different recommendations. The owner's manual will specify the correct viscosity and type of oil (conventional, synthetic blend, or fully synthetic) for your specific engine.

Using the wrong oil can lead to several problems including:

* Increased engine wear: The oil may not provide adequate lubrication, leading to premature wear of engine components.

* Seals and gaskets: Synthetic oils can sometimes be too aggressive for older seals and gaskets, causing leaks.

* Reduced fuel economy: Incorrect oil viscosity can slightly impact fuel efficiency.

Consult your owner's manual before changing your oil. The recommended oil grade will be based on the operating conditions and the engine's tolerances. If you can't find the manual, a Ford dealership or a trusted mechanic can provide the correct information.