164LS noise / water heater leak

On my 1994 164LS I've got a noise coming from the front of the engine that sounds kind of like a loose timing belt cover. Starts at idle like a buzz or rattle and then goes away when you get above 3000 rpm. I've got all new tiing components up front and also new water pump so I don't think it is those.

Also, was testing the AC and had a coolant leak develop somewhere behind between the engine and firewall causing steam like vapor to come out the top of the firewall area and also through the AC vents. I suspect a blown water heater hose or blown heater itself.

Any suggestions on eithe rof these items?