crackling car sounds

I've been wondering for years what inside car engines makes that weird sound. You know if you were driving for a while, and you park the car to hear a crackling sound coming from under the hood. What is that?

That's a "Really Bad Thing (TM)" :p

Could be anything - Air conditioning system, escaping air, etc.

It's really hard to say it you're not there in person th hear it.

How long has this been happening?

LOL, nice response Adept... :rolleyes:

The "clicking" and "ticking" sounds that are usually heard when a car is first shut down is due to the contraction of the different metals that make up the engine system. Dis-similar metals cool at different rates. The clicking and ticking sounds are the slipping of one metal relative to another, such as with bolted connnections, and car engines have a lot of bolted connections. The exhaust manifold connection to the head is probably the biggest sound producer since it by far gets hotter than any other component on the engine. It also has a lot of surface area to reject heat, so it'll cool faster than the engine block. The result...lots of noise. BTW, the reason you don't hear the clicking and ticking while the engine is heating up is due to the obvious...engine noise.

I guess what I'm trying to say with this long-winded response is that the clicking and ticking sounds are perfectly normal.

This ends my first tutorial in Mechanical Engineering 101... :D

What about those strange noises, that only your wife/husband seems to be able to hear ?

[quote]Originally posted by EvilCabbage:
<strong>What about those strange noises, that only your wife/husband seems to be able to hear ?</strong><hr></blockquote>

Those noises/burning smells are coming from the car/truck in front of you, not your car.

:D :D :D

Thanks Spaceman. So that's one of life's mysteries down, four thousand to go!