Hi Guys,

I think we all know the limitations/frustrations of Toyota Van cooling systems with enough hoses, clamps, and metal lines to irrigate a farm. I tried a pressure test and immediately thought I found the problem---cracked upper radiator hose leaking where it attached to the radiator. Replaced, still was losing coolant! Next, i discovered the leaking coolant recovery jug grommet. Fixed-it, yup, still leaking/losing a small amount of coolant. "Hose of Death"? Nope, last owner cut the access panel and replaced---dry. No puddles under car or in drive-way, seems to only leak when running.

The solution? Radiator Dye/Black light/amber googles. Run, turn heat on, get warm, drive around. Then, put the goggles on and turn the black light flashlight on---you can do in during the daytime---you will see it. I had a tiny split in a heater hose, near the battery box and makes a turn and connection to hard line toward the rear heater core. With the dye/glasses/black light the leak was ready apparent, glowing bright florescent green/yellow where the hose had a tiny split and was dripping down hose and onto the cross member. For less than $20, this method works great---I checked everything else (lines, hoses, clamps, coolant tank, head, Hose of death, water pump) no leaks/no glowing tell-tale signs. No leaks, no coolant loss.

Hope this helps someone. A normal "black light" bulb and cord and any amber colored shooting glasses would work as well and save you a few bucks.