My R53 overheated as I pulled it into my driveway yesterday... It was very low on coolant so I filled it and let it run with the fill cap off to try to top it off.

In the past when letting the car run I could see the coolant return flow a steady stream of coolant in the the overflow tank.. but now its kinda intermittently spitting the coolant.. and its bubbly/foamy. Is there an issue with this? If so how do I diagnose what the issue is? I'm not noticing any noise coming from the supercharger or water pump..

I replaced the water pump about 9 months ago when I did the head gasket. I also serviced the supercharger.. which was bone dry on the water pump side.

I need to figure out if I have a cooling system issue before the dog days of summer come.. Just don't want to damage the motor by overheating it. I also don't want to take the whole thing apart again of I don't need to.

 

Today I added more water and it seems to be flowing like normal.... It took a lot more water.. must of been bone dry.
Now.. the fun of finding the leak. any suggestions on finding mystery coolant leaks?