I have a coolant leak (passenger side somewhere near the timing belt because it was flinging fluid at me when I opened the hood and of course saoking everything so I couldn't tell where it originated.)

Here is the issue.

In the morning I come out to find the coolant completely empty and all over the driveway. I filled it and went to work. It sat all day at work without a leak so I figure maybe I overheated and it dumped. Get home no leak again. Next morning. Leaked to empty again. Repeat a second day with same result so I figure maybe it is temperature based and as it cools overnight a seal leaks so I watch for it last night and of course nothing leaks.

I am struggling to see how when pressurized it won't leak at all but can fully empty overnight and so intermittantly. Anyone have an idea how to force the issue so I can find the leak?

The only thing I can think of is that I was using the A/C on the way home but not to work. (Hotter in the afternoon drive time than in the AM but didn't yesterday when it was leak free overnight.)

 

Get a large piece of cardboard and lay it under your car after you get home from work. Then check for leaks about every two hours or so to isolate where the leak is coming from. Obvious suspicion is the water pump, either the seal on the unit, or the shaft bearing on the pump itself

 

I agree with OA. It sure sounds like a faulty water pump to me.