Hello guys.
We have this Crown forklift model C51000-40, we had it several time sitting down without moving it, as we took the radiator and fixed it.
Now that we started moving it again, the engine is making a rattling sound exactly as this video I found https://youtu.be/gLFv-4AdTgM ours is almost the same it only has short mast.

We noticed we have oil pressure, but we are not very experienced with this engine. Any thoughts on what we should do?

Thank you very much for your help!