Popcorn noise from engine bay.

[my dreamt dsm]

First off I don't even know what title to put for this thread.
Okay! Some random moments when I pop my hood I will hear a popcorn noise coming from god know where. I try to pin point it and sounds like it's coming from the back of the manifold engine block area.
The noise is hard to describe. It just sounds like popcorn popping back there. It's not to loud nor to soft either. I know it's not oil or radiator fluid boiling. I've experience that before.
It happens random, when the car is cold or after the car is warm from driving BUT only when the engine is off. I tried to take a video but my phone is really out of date(2003 samsung)

 

[PotatoFlakeSTi]

First off I don't even know what title to put for this thread.
Okay! Some random moments when I pop my hood I will hear a popcorn noise coming from god know where. I try to pin point it and sounds like it's coming from the back of the manifold engine block area.
The noise is hard to describe. It just sounds like popcorn popping back there. It's not to loud nor to soft either. I know it's not oil or radiator fluid boiling. I've experience that before.
It happens random, when the car is cold or after the car is warm from driving BUT only when the engine is off. I tried to take a video but my phone is really out of date(2003 samsung)

Catalytic converter.

 

[my dreamt dsm]

Catalytic converter.

???
I changed the stock to a high flow cat last week. Regardless of the cat, noise still happen with the stock cat and the hi flow cat.

 

[mattiouti]

Could it possibly be metal components expanding and contracting due to heat? I hear a similar sound when I get done driving my vehicles.

 

[1992 Eagle Talon TSi]

I have a very similar sound coming from my car didn't start until I put a highflow cat on it. Didn't have a cat on it when I bought it and it never made that sound. So I figured it was the cat.

 

[Afizzle]

after driving if you get down and stick your head under the middle of your car youll hear all the metal exhaust piping crackle and popping from it cooling down after expanding from heat.

 

[my dreamt dsm]

I rule heat out of the factor because it happens regardless, even on a cold motor.
I know it's hard to diagnose without a video clip and over the net. But throw out your opinions and I'll try to rule it out by test or theories

edit:
Yeah, I understand the catalytic converter sound you guys probably talking about. The cat noise is more of a crack then a pop.
It's around the manifold area, high. Not as low as the catalytic.

 

[mattiouti]

What kind of exhaust gaskets are you using? How long has it been going on?

 

[my dreamt dsm]

What kind of exhaust gaskets are you using? How long has it been going on?

It's been about 1 year old. I changed all my exhaust/ turbo related gasket when I did my 16g install. My turbo has been on my car, a little over a year.

 

[mattiouti]

Hmm. Only reason I asked is because I used a cheap o2 gasket once and it smelled and cracked from time to time and when I went to replace it, it literally disintegrated upon removal. After that I was good to go.

 

[Archer Fabrications]

Id say exhaust leak, check manifold
For cracks.

Edit: nvm didnt see it was with engine off, id say its just expanding and contracting of metal,
Totally normal.

 

[NoHndlbrsRqrd]

It sounds like regular heat cycle noise to me. Mine has made similar noises due to the heating and cooling of components.

 

[boost97gst]

You say it ONLY happens when the engine is OFF, correct. After driving it? Heres a wild thought: ac system.
it can make some pretty weird noises. My 99 expy has all kinds of bubbling and weird sounds after i shut it off. Its pressure in the ac lines. Works fine for over 240k miles now though .

Other thought is i agree with others who said it could be metal contracting. That can be a strange sound too and its more likely the issue.

 

[my dreamt dsm]

Yeah. But it also happens even when the car is cold. Like in the mornings sometimes?

Marco. Polo.

Okay, I've log evoscan a few times and it keeps popping up vss (vehicle speed sensor) Any ideas? No engine light btw.

 

[clipto]

Does it sound like this? https://www.youtube.com/watch?v=ophPbHD8Fzo

 

[2slow4now]

So it does it hot or cold but the car is running. I bet you have an exhaust leak.

You mentioned something about replacing gaskets before. Did you ever retorque any of those after they went through a heat cycle? How smooth and flat were the gasket surfaces? What gaskets did you replace? Also what style? (composite, copper, multi layer steel) brand? Did you copper spray them?

It's almost always a good bet that if you do something to your car and something starts around the same time that something related to what you did is the culprit. Cracked gasket, not sealing gasket, over torqued, unevenly torqued, or maybe the manifold, O2 housing, or even the turbine housing cracked or had a crack.
Do I get a cookie? No cookie? Ok how about a beer?

 

[my dreamt dsm]

Does it sound like this? https://www.youtube.com/watch?v=ophPbHD8Fzo

No! Not that loud and at a faster interval.

So it does it hot or cold but the car is running. I bet you have an exhaust leak.

You mentioned something about replacing gaskets before. Did you ever retorque any of those after they went through a heat cycle? How smooth and flat were the gasket surfaces? What gaskets did you replace? Also what style? (composite, copper, multi layer steel) brand? Did you copper spray them?

It's almost always a good bet that if you do something to your car and something starts around the same time that something related to what you did is the culprit. Cracked gasket, not sealing gasket, over torqued, unevenly torqued, or maybe the manifold, O2 housing, or even the turbine housing cracked or had a crack.
Do I get a cookie? No cookie? Ok how about a beer?

It only happens when the car is off. It was steel gaskets and also sprayed with copper. It isnt happening towards the front of the car.

I'll look on youtube to see if I can find a clip similar to it.

 

[4g63t]

My car has been doing the same thing for years. It can't be anything bad. Mine sounds like it is coming from inside the valve cover. Almost like it is the lash adjusters retracting or something with the hot oil sitting on them. My evo even does it every once and a while.

To be clear it is a single pop noise, that repeats randomly. Not a constant rapid noise.

 

[my dreamt dsm]

Working on the video.

Not sure if you guys can see the video. I was washing my car and cleaning the engine bay. I happen to catch the noise in time. My phone so shitty I had to use my brothers iphone to record my phone. Cause my phone can't even text, bluetooth the video so it came out upside down. SORRY!
This is DSM revival's facebook page.
https://www.facebook.com/video/embed?video_id=485722938167777

This is about 2 hours of cool down time from driving 15 miles. ENGINE IS OFF! Although it sounds like the car is on. There is no key in the ignition.

 

[Lemony]

Think it's engine pinging/detonation? Never personally had any of my engines do it but it's not uncommon for older cars. I've watched YouTube clips and it does sound kind of like popcorn popping in a metal can. Check your timing, if your timing is good maybe run some fuel system treatment through it to loosen up any carbon that could have built up in the combustion chamber.

 

[Archer Fabrications]

^ he said engine is off, i haven looked at the vid i domt have facebook.

 

[my dreamt dsm]

Sorry guys for those who don't have facebook. I'm trying to load it onto youtube.

CAR IS OFF AND NO KEY IS IN THE IGNITION!

 

[my dreamt dsm]

TO HELP FUTURE DSMERS OUT with this post. not sure you'll consider this popcorn noise.
Recent threads been popping out on ISC so I decided to think that is my problem. Im sorry I couldn't get you guys a sound clip until now. this is not my video but it sounds exactly like this. It doesn't happen at intervals. It makes that sound constantly for like 10-20 seconds. I don't have a volt meter but I'm pretty sure it's my problem.
[ame=http://www.youtube.com/watch?v=q9kgVPT4QLM]Bad dsm isc - YouTube[/ame]

Here is another one of my thread that could back up my claim. BTW no check engine light at all.

 

[crimsondragon]

But your car is off so there shouldn't be any power going to the ISC. Unplug the battery and see if it goes away.

 

[my dreamt dsm]

But your car is off so there shouldn't be any power going to the ISC. Unplug the battery and see if it goes away.

I'll unplug it if it ever happens again. Like I stated, it happens randomly. I haven't heard it for months now. I'm just going to replace it.
My other thread that consequently relates to this.
http://www.dsmtuners.com/forums/drivetrain-tech/470821-could-clutch-problem.html