Lydia

I have recently purchased a 52 s2000 and when I start the car cold it's fine and as soon as the engine warms a ticking/humming noise starts. I will upload a video of the noise later I was just wondering if anyone had any ideas on what I may be looking for?

Akaryuu

Is it only when it's idling or does it happen the whole time it is running?
Does the sound increase in sound and speed when the engine RPMs increase?
How many miles does the car have?
Is there a loss of power when the motor is cold versus if it is warm?

These things are always hard to diagnose via the internet, but perhaps some of the more experienced S2000 guys here have an idea of what known S2000 common issues it could be.

Vanishing Point

What is your oil level when cold? May be as simple as low oil level.

Lydia

It does it the whole time it's running, but stays at the same level of noise/ speed at any rpm. The car is on 75500 miles, it has a slight difference in power but that would just be down to he running temp, it's nothing out of the ordinary. It has been using more oil than usual but I have kept the oil level up.

rob-2

Video would be required. These motors aren't quiet and my general thought is you're comparing it to another quiet motor.