any ideas what the cause might be? I've got a 1mz which has been running fine for about 6 years now I guess. a few months ago a hose popped off round near the alternator. then a different one came loose between filler cap section and some rubber hose, and today a hose going into the engine block (above the gear shifter linkages) came off and caused more havoc on my way home.

the car hasn't been running hotter than normal, and no sign of coolant in oil a few weeks ago when I changed it. I had to remove the large core alloy rad recently as it was leaking both ends near the hoses, but now I'm starting to think maybe the leak was between the rad and hose rather than through the fins. I chucked an OEM rad on and temps have been fine (warns up a lot quicker that's all).