So I changed the radiator and thermostat on a 2004 rx8. There are no water leaks, and resivoir is full with water, but the low coolant light comes on when I accelerate. After a little bit of time the low coolant light goes off.

It's dark now and I'm going to check it out tomorrow. Maybe clean out the electrical connection. The BMW's at my work sometimes show low coolant if there was water in there.

Anyone have this happen to them? It's just kind of weird that it comes on and off with acceleration. I'm hoping it's just maybe a little water in the connector

 

Air bubbles. The coolant system hasnt completely burped itself yet. When you accelerate, g forces push the coolant away from the sensor which then sees air and trips the light.

 

Ic, what's the best way to bleed out a rx8? It's already been drivbing for a while and the same problem happens. I was hoping after a few pressure cycles it would bleed out. I already ran the car with the coolant cap off and heater running

 

I would've thought just running it and monitering the overflow so it doesnt get too low wouldve done it. I'm not an Rx8 guy so i wouldn know, but this happened on my previous FC and i got so tired of the buzzer still coming on that i pulled the sensor on the rad and filled some coolant through there...it actually worked for me but i dont know how different in placement the 8 is.
You should also check for leaks if you haven't. And inspect the overflow hose for fitment and any possible damage starting where it's not dipped in. Reason being to make sure it's pulling coolant and not the air above it. I'm sorry I couldn't be of any more help.

 

Thanks for the help. Yeah, it's not leaking. I'll try something out to see if I can get another air bubble out.