Rattle on Startup

Promted by exploder, I thought I'd ask about my rattle in my 1HZ on startup.

I noticed it recently in Tassie at cradle mountain, when it was mighty COLD. On startup, there was a rattle that lasted 5 mins or so. I had noticed a rattle previously but it didn't last long as it wasn't -2 degrees overnight.

When down from the mountains, I left it at a "toyota" dealership overnight, and went and started it up the next morning when cold (but not cradle mtn. cold)

The mechanic there gave me a strange look as it turned over first go without much of a rattle. (if at all) but it wasn't that cold.

There was definately a rattle in Tassie, and there is still a slight one here in SA, but it doesn't last for long.

Anyway...he told me that a rattle when cold was pretty normal, and some of the older ones backfire and blow smoke till they warm up.

So I'm wondering if anybody else experiences this, am I just being over paranoid?

My wife could hear it in Tassie, and when she can hear it, I know something is different as she doesn't have a mechanical ear if you know what I mean.

Thanks again girls/guys