Hello baludoy, niky, zman and v6dreamer. It was a long weekend for me so I just read your responses. I greatly appreciate them. Long din yung response post ko so please bear with me. sensya na.

Travelled a total of 180+ kms over the weekend and ended up refilling around 800ml of water on the rad when I reached my destination same as when I got back home. Container overflowed again and few very light brown water marks sprinkled on my windshield and bumper. Mukhang galing sa overflow container kasi medyo ganun din kulay ng tubig sa loob ng container. I also have to spill away excess water from the overflow container para nasa full level lang sya. Steady lang naman sa 1/2 yung gauge kasi siguro dahil walang uphil. I just drained and refilled my rad a month ago. Kelangan ko na ata pa overhaul ang rad ...

sarap sana laging mag byahe kasi 21.50 nalang diesel kaso my cooling system is faulty.

I have checked the surrounding objects of the water pump but didn't see any leakages. Water is normally circulating and no foul smell even after a long drive. Fan is also ok.

Checked the small hose connecting the rad to the overflow container for possible micro holes but none.

Wala akong thermostat since then pero dati meron about 3-4 years ago. Not sure pero do you think we would be able to get to the root of this assuming the thermostat will resove the problem?

I am considering using a coolant after I spot the problem. I saw a 50/50 pre dilluted from prestone. Ok ba eto for diesel? and sabi sa intructions is no need to add water ... what if I do? Meron din concentrated from the same brand. which do you suggest?