^ I would suggest bring it to another mechanic, saan ba yung location mo?

baka nga kailngan na nyan ng top overhaul... yung tubig ba sa radiator mo may halong oil? brown ba yung kulay?

malamang you have a leak somewhere, hindi naman mag evaporate ang half liter in two hours, check mo hoses, radiator, water pump

im driving civic 96 AT as well, pag nag top up ako ng tubig sa reserve mga 100 ml siguro in 1 month