There appears to be a leak in my cooling system but I cannot trace it the source. Here is what I know: 1. When the level in the holding tank gets low it seems that air gets into the system and prompts a drip a second from just foreward of the passenger rear wheel. 2. The temperature cycles to about 195 when the thermostat opens, fall back and then the temperature rises and the thermostat opens again, temperature drops and the cycle starts over. 3. This evening when it happend I pulled over and bled the air out of the radiator. There was a lot of air in it. 4. After the air bleed the temperature stabilized below 195 and the TS opening/closing stopped. 5. When I got home there was no leakage although over a week or so I will have to top up the overlow tank. 6. My conclusion is that air gets into the radiator, heats up and put more pressure on the coolant causing the drip referred to in 1 above. If enought air gets into the rediator I will get a flood of water coming out. This prompted me to change the water pump a month or so ago when I now believe that I did not have to. See earlier thread on this. Appreciate any thoughts on this.