do you have an pressure tester for the rad.....get on youll find your smell fast however   does your window fog up sometimes ?????? if it does its your heater core.    however you should pressure test you cooling system anyways trust me it's the only way to find your antifreeze smeel. instead of guessing what it could be. your loacol napa should have one or auto zone will rent you one .  good luck

I can vouch for the intake manifold problem. My 84 had about 61k on it when the water pump expired. Since I have way too little tiem to do much on the Vette, I had my mechanic inspect for more then the obvious. Sure enough, there was a drop or 2 of coolant around the intake. Since he was replacing the water pump, I saved some labor costs by having the intact done too.