Antifreeze Disappearing

[johnl]

I had a mystery leak before and it was not a head gasket.

Yes, but Kev has loss of coolant AND bubbles. Gas in the cooling system has to come from somewhere. Keeping in mind that the severity of a leak caused by a failed gasket can sometimes vary depending on engine temperature, and pretty much always vary depending on engine load (cylinder pressures), a leaking HG will introduce a probably small but more or less continuous stream of small bubbles.

Assuming the system was correctly filled in the first place, the only other source of gas in the coolant is the gas created by boiling the coolant, but that doesn't seem to fit the described symptoms here.

[Binladin]

Just for reference… Coolant loss every 2-3 days witout bubbles, refilling overflow tank as it went down.

I had a mystery leak once for a week or two that turned out to be that damn metal coolant tube running from the water pump to the thermostat housing which had a pinhole from rust. I only caught it leaking a dribble on the ground 10mins after shutting the car off one day while I was out and still couldn't find the leak so I went about my bizz since I had spare sizes of coolant hose in the trunk… 30mins later the hole must have gotten bigger and the temp started to rise so I pull over to find coolant leaking from the back of the block, like wtf… stupid metal tube I can't fix on the spot!:/