Random question, would that obnoxious buzzer go off from a cracked/clogged filler neck? I have not touched my Turbo2 since last spring. Coolant system has been burped, my radiator has been pressure tested and flow tested outside of the car, with no problems. I know oil system can set off the buzzer, however my idiot light cluster does not work. I have ZERO bubbling when I burped the system.

And I should probably know this, but would blown coolant seals also set off the buzzer?

 

AS far as I know, the only thing that sets off the buzzer is low coolant level and low oil level. In my case, there was enough leakage to cause the buzzer to go off, but filling it back up again shut it down until the next time.

Of course, if you have a defective sensor, I would expect that it would default to the buzzer going on rather than it just not working.

If you are losing coolant, check that filler neck. I had no idea it was plastic and could not see the crack until i really looked for it.

 

all of the above can set off the coolant buzzer, so can the common broken wire leading to the sensor itself since by default if the loop is open it will trip the alarm. i don't immediately assume the engine is bad, a pressure test is the best place to start unless your plugs just come out soaking with coolant and there is no external leaks and coolant has been going missing.

 

Sensor was replaced as soon as I got the car along with a thermostat. Both OEM from a Mazda dealership. The wire for the sensor is not broken or cracked anywhere. I also replaced plugs and it was just the typical blackness on the plugs from running too rich.

Would a defective oil level sensor trip the buzzer as well?

And now that I remember, when I burped the system completely, the buzzer went away for a good 3-4 weeks. I put probably 100 miles on it in those 3-4 weeks, but then it resurfaced. I did burp the system at the filler neck on the radiator. The person I took the radiator too recommended that I burp the system at the sensor bung. What he explained to me seemed logical, but I'm still skeptical on doing it that way.

 

the oil system works in reverse from the cooling system, an open wire in the oil switch means the buzzer won't work at all, when the oil level is low then the float falls and the sensor is then grounded. in theory if your oil level sender wire is shorting to the body, then it could happen, i just have never seen that occur, not that it can't.

you should have the whole system pressure checked to see if there is any leaks you didn't notice with it running. problem with finding leaks on a running engine is the coolant can evaporate before you spot it.