where is the noise coming from? What is the temperature? are you too hot and the water is boiling? Do you have an expansion tank? If so it could be shot.

Is it from the circulator?

Need more info and likely needs to be experienced first hand. Call a service tech to take a look.

I think the niose if coming from where the spiny wheel is (dont know what it is called) But if i put my head of to the furnace i can hear it very clear. It is so loud. I have the temp at 70 degrees. No expansion tank. it is a goodman furnace about 10 years old.

That spiny thing is called a squirrel cage fan.

Make sure the furnace is off and try to wiggle the fan. If it wiggles even a little(side to side or up and down, the bearings are bad and can be or cause the rattle.

If the fan does not wiggle, get a small mirror(unless you can see into the fan housing) on a stick, a flashlight and inspect the fan and housing inside. Look for something sticking down in the fan(happened to our furnace) of maybe see where the fan is hitting.

Remove 4 screws holding motor cover and pull cover off. Using a 3/8ths drive ratchet with 7/16ths socket tighten bolt at 2 o clock on motor frame. clean fan,lub motor and replace cover. While you are in there tie that loose black wire up.

My advice is this:

#1) follow the steps described by others from previous posts.

#2) If the Squirrel fan is dirty, clean it. compressed air is the easiest if you have an air compressor, or have a friend that does. Otherwise, dig out the brushes (large ones, small ones & even the toothbrushes) & start cleaning. Cleaning the squirrel cage may or may not, solve the rattling noise.....regardless though, a clean cage works less harder & produces better air flow.

#3) worst case scenario:
Call a furnace repair shop & have them look into it.
I can promise you that if they hear the rattling, they will either know what it is and/or be able to fix it if at all possible.

Footnote:
Calling a repair shop(especially on a weekend) is very expensive...but it almost always gets the problem solved.

My blower motor died. They replaced the entire cage assy. Left me old one. Says they do it all the time. We had maint plan back when we bought house. Have new furnace now.