Q: Noise in the frontal area off the engine near the fan

after almost 100 km of off road travel, getting stuck, helping other by pulling them when they were stuck, in a lose sand area, when i arrived home, suddenly we are surprised by a a relative loud noise like something snapping and starting to knock in the frontal area off the engine, synchronized with the engine rotation noise. the noise i can describe as like if my engine was sounding like a Diesel engine, since my engine is a petrol one, the knock it makes is sound similar ( not in a literal way ) , but aware that it is something knocking. The car is moving, i can drive it, also i felt like it is somehow without his normal power, and seems being burning with some difficulty, some people say that may be a valve, or the timing belt, other may be the traction. Please Help me
My car has an automatic transmission.