I replaced a leaking water pump and thermostat on myc ar a week ago. The low coolant light came on, and upon inspection it was low and took quite a bit of coolant. I filled and bled the system and it runs at a good temp, sitting is a little higher than i would like. After you drive it and take it to temp, it dumps coolant out from somewhere and the low coolant light comes back on, and the process starts over. What is the culprit? I fill the radiator to the top, then bled it a couple time, and the resovoir is full too. Anything sound wrong?

 

Theres a few possibilities, to start how much coolant did you put back in? maybe its not completely full and needs a good bit more bleeding?

After that is there any coolant in the oil? Do you have an oil cooler? and is there any white smoke/steam out the exhaust?

 

I hope that it is just not full yet. When I bleed my coolant, I fill it up, take it up to temp, fill it back up, take it up to temp, fill it back up, take it up to temp and so on. It takes a few cycles (even more with a stock WP, I have elec wp) to get all the air out of the system. If it is leaking though, you should no doubt see a puddle or notice white smoke and just track that down (hopefully no white smoke).

 

I had a problem with my car dumping coolant one time and it was a return line that ran under the battery that was dumping coolant, might want to check there as well.