About 2 months ago I fluched coolant and after that the add coolant light has come on more often. I add distilled water to her and it goes away for a while not it comes back like ever 3 or 4 days ????

I have replaced the pressure cap with another OEM Mazda one to no avail

 

Did you bleed ALL the air from the system? I had this problem before- you would be surprised how that blasted air bubble makes life difficult. Just make sure as you are topping off that you leave the bleeder screw cracked a bit to let air escape. If there is any air in the system, and that sensor gets dry, then that sensor will drive you batty. Also, you didn't metion the thermostat- have you changed that as well?

 

No i have not changed that yet but if this keeps up I will

 

I dont think it is the tstat b/c the temp will stay down untill the add coolant light comes on. Then after i have put water in the temp drops back to 1/4 of the guage

 

Then all I can say is, check really closely for leaks- specifically on the hose that comes from the firewall on the driver's side, and passes close to the oil filter- that one gets oily and deteriorates- might be cracked slightly and sprays out a fine stream of coolant when hot. Hard to find- but it will do exactly what your symptoms are.

 

Thanks i will check it

 

You must properly bleed the system as described in the Haynes/factory service manual. If you don't air bubbles will cause all kinds of problems.

Also, as mentioned, check the hose between the rad cap and coolant bottle. Better yet, just replace it. Any leaks will be too small to see.