So I have a slow coolant leak that I cannot find. I have replaced the heater hose, thermostat, and thermostat housing. I am still losing about 1/5 of a gallon of coolant every week and a half to 2 weeks (I don't drive long distances). Pressure testing (only done cold, is hot worth doing?) reveal a leak and the system maintains pressure. I have tried florescent detection and found a minimal amount of signal under the car, behind the block on the clutch cables (manual 4 cyl engine) but I cannot identify the source. Replaced parts are clear of florescent signal and dry. There is no noticable signal in the oil. Any suggestions? On where/how to look or what to replace? I need to find it soon as winter is coming and I need to replace the water with real coolant. Thank you all in advance for any help.

 

Headgasket leak. RIP