A ticking/clacking noise has been getting louder in my engine in the last 400 miles. I can't tell if I have clacking valves/lifters, or a leaky exhaust manifold. Is there a simple way to tell the difference? I suppose I'll have to see a mechanic either way.

KonaYota, '92 4Runner, 3.0, 291000 miles.

 

Look over your manifold and see if you can see white carbon where it connects. Also, look at the connection of the header pipe to see if it's white. Is it louder when it's cold? Usually the manafold leaks will quiet down once it warms up?