Why do car engines make ticking sounds when they stop running?

[NFS4]

I know with some cars, after it's been running and you turn the engine off, it makes tiny popping and clicking sounds from the engine.

What EXACTLY is doing the ticking and the popping? Expanding and contracting of metals?

 

[MichaelD]

Hot engine oil dripping from the heads/block into the pan, as well as the metals cooling.

 

[WinkOsmosis]

My car does that. I always figured it was dripping or something. It sounds like it comes from behind the engine. I also hypothesized that it was metal contracting, since it kind of sounded like it was coming from the length of the car.

 

[Angrymarshmello]

The hamsters running your Camry are just scurrying back up to their cages

 

[notfred]

Exhaust pipes (and some other things that get hot) shrinking.

 

[JEDI]

Originally posted by: RagingBITCH
The hamsters running your Camry are just scurrying back up to their cages

rofl

 

[Eli]

Originally posted by: notfred
Exhaust pipes (and some other things that get hot) shrinking.

Yep.. It's got nothing to do with anything dripping. It's just the metal contracting as it cools.

You'll notice that wood stoves do the same thing.

 

[StageLeft]

Originally posted by: RagingBITCH
The hamsters running your Camry are just scurrying back up to their cages

:Q

 

[BigSmooth]

Originally posted by: RagingBITCH
The hamsters running your Camry are just scurrying back up to their cages

LMAO.

NFS4, you left yourself open for that one.

 

[SSP]

Originally posted by: RagingBITCH
The hamsters running your Camry are just scurrying back up to their cages

I was literally LMAO!

 

[Amused]

It's the metal contracting as it cools. Oil dripping inside an engine wont make this kind of ticking sound.

 

Exhaust pipes (and some other things that get hot) shrinking.

Bingo, give that man a dollar.

Exhaust temps regularly reach 1,300 F, this includes the catalytic converters, as soon as you turn the engine off, the exhaust components start cooling, this causes the metal to shrink in size causing the popping sound.

 

[cavemanmoron]

Originally posted by: Eli

Originally posted by: notfred
Exhaust pipes (and some other things that get hot) shrinking.

Yep.. It's got nothing to do with anything dripping. It's just the metal contracting as it cools.

You'll notice that wood stoves do the same thing.