Car makes noise -- when it's off!



My 1997 Mitsubishi Mirage is parked just outside my window, and for the past 2 hours it’s been making an odd humming noice every 45 minutes or so – even though it’s off. The noise lasts about 20-30 seconds, then stops. I haven’t driven it today, and it didn’t go anywhere yesterday either. What on earth could this be?

I’ve heard this noise periodically while driving, too, for the past 2 months or so. And it’s also been really hot for the past 2 days. Any connections there?



Check the engine fan and see if is coming on…for some reason the sensor thinks the engine needs cooling…


I agree, it’s most likely the fan.
When it’s making the noise pop the hood & see whats going on.


So if it is the fan, what would that mean? A bad sensor? Or would it just be doing its job?


Perhaps the relay is stuck.


i agree wih the ‘bad relay’ thought.


Thanks, everyone! I’ll check the relay out!


Often, one relay can be swapped with another, say, the horn relay, for the fan relay. The relays are often in a box under the hood. The engine coolant temperature sensor is the other part which can cause the engine cooling fan to come on when the engine is cool. Try the relay, first.