Odd sound at start up?

[Hochspannung]

Alright so it is very cold here, like -15C cold. When I started up my car today when the motor was cold I heard a "Pop" sound. Its the kinda of pop that is like when you drop the needle on an old record player or a speaker pop. It was loud, and it didn't really have a specific place the sound came from. I thought at first it was so cold that the speakers did indeed make a "pop" sound when I started the car. But another time I made sure the radio was off and I still got the same "Pop".. so now I'm not so sure it was the speakers?

Anybody ever experienced this ?

[telijah]

Does the sound happen when just turning the key to the accessory position, or does the sound only happen when you actually start the vehicle?

[Hochspannung]

Good question. I only turned the key in one continuous motion, I only assume it was when I cranked the motor. Let me go check now before I take off to the gym.

**EDIT**

I just checked. It's only -2C today (thank God) The sound did not happen at the accessory position (#2) nor did it happen when I started the car. It must have been something to do with it being extremely cold. My heater also made some squealing/whirring noise yesterday during start up.

[telijah]

Hmm, maybe the pop is the starter kind of sticking in the cold, and the pop is when the shaft finally un-sticks...?

[Hochspannung]

Who knows.. To me it sounded like all the speakers popped. I would say it was definitely from inside the cabin and not from the engine bay.

[M3TA5IN]

My car has also made a similar sound on start up in the cold. Although it's the coldest it's been now (15F) and hasn't done it. I can't figure out what it is.

I also have a ticking sound at idle, but I believe that is the lifters.

[Hochspannung]

i read that it could be a wire from the radio that the casing is cracked on and without the insulation it will make a pop sound through the speakers. Once you find it and cover it with tape the pop will not happen.

[llll1l1ll]

That sounds plausible.

I can't imagine a sound like that coming from the engine and the engine remains just fine. Usually pop sounds like that denote a nasty engine failure.

[Oli77]

I have heard it occasionally on very cold days and always assumed it was that secondary air pump kicking in. It sounds like a diaphragm pushing air.