I have an '83 300 SD Turbo Diesel that's blowing lots of white smoke out the exhaust. The smoke has a touch of powder blue to it and it smells like oil to me. If it was a blown head gasket it would be steam, and my coolant level would be way down most likely, right? I removed the air filter thinking it might be clogged since it hasn't been changed in about 2 years, but the problem persisted. What could it be? It just started happening and I have a slight oil leak all the time so I can't tell for sure if It's been burning oil for sure. It sure sounds like it though, doesn't it? Isn't blueish white smoke a dead giveaway? What could it be?

Thanks