Redstone engine turns green?

[NosajDraw]

My redstone engine is working just as I wanted it to, taking stuff from my macerator to a chest.

I read as much as I could about restone engines, and apparently they don't explode if connected to a wood pipe, which mine is.

However it has turned green from blue, which I understand is stage one towards yellow, then red then explosion.

Do I have a problem? How would I fix it if I do?

[NosajDraw]

Oh my, it turned yellow, I turned it off

What am I doing wrong?

[saintnicster]

That's fine. It just means the engine is warming up. The "warmer" it is, the faster the strokes/pulses are.

I believe that the engine will blink between orange and red when it is at the optimal/max temperature for the redstone engines.