|Subject : 2004 3ltr Terrano|
Whatever coolant additive you have in the system will leave a trace of that colour from any leak..so go over the exterior of the engine with the engine off but hot as in just after a good run.. Pay special attention around the water pump area; it is obviously happening when the system is hot, and the pressure in it is 14lbs sq inch. If the leak is external, fine droplets will come out then and should leave a mark, or a very clean patch somewhere on the engine...
Otherwise you will have to pressurise the system by attaching a special pump to the radiator neck, and look for leaks. It may come to having to take out the injectors after leaving the pressure on for say 48 hours, and seeing if coolant comes out of any cylinder when you spin the engine over with the starter, as the coolant will be thrown out as the pistons go up and down...That would confirm a head gasket breach into the cylinder. The leak could also be into the engine oil galleries so look for more than usual- in- winter moisture induced emulsion. (Creamy foamy oil) Good luck.