dholmes920

my wife has a 2009 civic ex and one day she her ac stopped working and her car overheated. all antifreeze was gone with no signs of leaking, no white smoke from tailpipe, no smell inside and no milky or discolored oil. filled with water for the time being and then it was fine. still no ac. tried to recharge at low pressure ac line and pressure was high. we ignored it for a year and then her ac pulley bearing started to go so i bypassed it with smaller belt. she is currently losing all antifreeze from reserve bottle in a three week period with no signs of any leaks smells or discolored oil. engine is rough when cold then goes away after warm up. no overheating. dont know if this is connected but when engine is cold and put into reverse it makes a horrible sound that i cant even describe then goes away after warm up. im perplexed. i did replace water with honda antifreeze before winter hit 2 months after ac went.

Jimi Hondrix

A/C issue and coolant loss unrelated.
Coolant loss is either external leak (hoses, radiator, reservoir, etc..) or internal leak..breached head-gasket: coolant leaking into cylinders and being expelled through exhaust.However, white smoke not always present.
Do a cold and hot (operating temp) pressure test (rent free tester at auto parts store). Do not exceed spec psi of coolant system.
Do a Block Test (free rental) to rule out head gasket breach.

Could be as simple as a the thermostat is stuck closed or reservoir has developed a leak. Other suspects include failing or failed water pump (can leak when completely failed). Check to see if coolant fan engages.