hi ya boss,
first procedure, check ur engine, especially on head cyl area, is there any water leakage ? if yes, then
the reason water got into the system, some of the frequent causes is :
1. check the bolt on ur cam chain gear, here in Indonesia some early production batch already has that kind of problem, look at the parts list manual book code 5YP–E2157–00 BOLT, it's either not properly seated/tightened, or better to apply a little threebond sealer on it before tightening.
2. check engine gaskets, upper, apply threebond sealer on the head cyl gasket to prevent leaks.
3. check the tightening specification on head cyl bolts.
4. check this part 93103–10801 OIL SEAL on the water pump and the o-ring water pump.
Hope this helps.
Recommend to flush ur engine first with diesel fuel or an aftermarket engine flush. Then apply that X**O revitalizant to protect the engine.