[jmatta]

I agree with replacement...mine on has 19k miles, but is original to the car and nine years old. I've read the horror stories about cracked heads and feel proactive measures are in order; just wish I would have done it a year/half ago, when I installed the LN low temp t-stat and renewed the coolant.

OP, I'd be very leery about running the engine, knowing the passages are likely blocked...the experts will hopefully chime in, but I see some engine disassembly in your future.