Missing coolant is the LIM or head gaskets. Might as well change the head gaskets, it's got plenty of miles. Preventative maintenance.

 

While doing all this, check the plastic UIM (not gasket, the actual UIM) for damage around the EGR stove pipe (it goes between two coolant tubes that flow coolant through the throttle body). The heat from the EGR tends to make the UIM brittle there, develop a leak and now the car might exhibit symptoms like a bad head gasket when it was something far easier/quicker/cheaper to fix.

 

I figured it out I'm cleaning the engine now

 

Take out your oil pan and clean out the sludge out of it while u at it, this is a sure way you will remove all the antifreeze out and for good.

 

I have a 02 3400 and im having the same problems can you please help me out with whatever advice you have please?