Why is my 86 rx7 blowing out white smoke and it wont stop but runs fine?

When you mean its blowing out white smoke... you mean out from the exhaust pipe right? Not anywhere from under the hood or inside the car? Usually when white smoke comes out the exhaust it means that its not burning the fuel all the way... smell around if it smells like gas. If you smell fuel then check things like the fuel injectors - they can be leaking and need replacing...or maybe just the injector ring need 2 be replaced. Check compression. Check if their are any vacuum leaks and check intake system.

hey bro it sounds like ur coolant seals are bad