How much diesel rattle is too much?

I've had a Ferguson TO-30 for years (gas) and I am used to an engine rattle as being a sign of bad things happening inside. Well now, being fairly new to owning a diesel engine, I'm having trouble getting used to the noise these things make. I bought a new to me John Deere 4200 a few months ago with the 3 cylinder Yanmar. It's now got about 1090 hours on the meter of which I am responsible for nearly 50 of. I always warm it up before using it and it is a bit louder on start-up, but how do you know if a diesel is too loud?

We probably have nearly a dozen diesel trucks (Powerstrokes) in our fleet here at work and I will occasionally ride in one with one of the foremen and the rattle they make is even louder. Is it something I will eventually get used to? I keep imagining that I hear it sounding different and find myself checking the oil a lot just to settle my nerves. I changed it when I first got it and went with Rotella 15-40 Diesel oil, at the recommendation of our shop mechanic. He claims really good success with it here at work so I'm sure that's not a problem. It's in my head, I'm sure of it. You think I'll every get used to the noise?

Can someone explain to me why a diesel rattles so much anyway? I truly am a rookie when it comes to diesels. Thanks for putting up with me "rattling on"............. :empathy: