Engine getting loud

[Bl4d3]

Hey all

So I have a 2012 Chevrolet Sonic 1.6 hatch (not 1.8).
I've posted here because the engine is basically identical to the 1.8, just being a smaller volume.

The engine has progressively been getting louder over the last 2 years.
No intake leaks, no bad ticking noises, no underperformance, etc.

I've spoken to another Chev Sonic 1.6 owner and he has a similar problem, so I've started to think that its normal for the car until I just did a 800km journey.

Now the car sounds like it is a straight pipe at about 3000 - 4500 rpm. Its unbearable.


I'm installing sound deadening in the bonnet, boot, floor pan and firewall to try help (doors already done).


Any suggestions on what the problem could be? Im taking the car to an exhaust specialist on Monday to also check for any leaks

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[Gobinator98]

Hey all

So I have a 2012 Chevrolet Sonic 1.6 hatch (not 1.8).
I've posted here because the engine is basically identical to the 1.8, just being a smaller volume.

The engine has progressively been getting louder over the last 2 years.
No intake leaks, no bad ticking noises, no underperformance, etc.

I've spoken to another Chev Sonic 1.6 owner and he has a similar problem, so I've started to think that its normal for the car until I just did a 800km journey.

Now the car sounds like it is a straight pipe at about 3000 - 4500 rpm. Its unbearable.


I'm installing sound deadening in the bonnet, boot, floor pan and firewall to try help (doors already done).


Any suggestions on what the problem could be? Im taking the car to an exhaust specialist on Monday to also check for any leaks

Sent from my SM-G965F using Tapatalk

You probably got an exhaust leak near the front of the car. And it’s probably a leak that you can’t see because it’s on the “top” side of the pipe(if you are looking at it from underneath).

Open the hood and take a look around while the engine is running. Do you smell exhaust? Can you get under the car and feel/look around for the leak yourself? It’s not extremely hard to do at all. Just see if you can see any holes and feel around with your bare hand where you can’t see. Obviously make sure to do it when the exhaust is cold as it can easily reach 1000°F or more.


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[TitanBlue]

A full service mechanic shop may have a smoke machine, which will put smoke into the system and illuminate exhaust leaks quite quickly.

 

[Gobinator98]

A full service mechanic shop may have a smoke machine, which will put smoke into the system and illuminate exhaust leaks quite quickly.

You can check it just as effectively without seeing a mechanic with a machine. Just trying to save him some money. [emoji849]


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[Bl4d3]

I actually have a 700w smoke machine, I'll connect it to the exhaust and see if there are any leaks

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[Gobinator98]

I actually have a 700w smoke machine, I'll connect it to the exhaust and see if there are any leaks

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That’ll definitely work. Obviously will find the hole a little bit faster and have no risk of burning yourself if you are feeling the pipe for too long. If I had to take a wild guess....there is probably a leak in the flex pipe after the cat or in one of the mufflers. Usually when an exhaust leak gets bigger, the car sounds louder.


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[Bl4d3]

So tested using the smoke machine, paid attention to the flanges, flex pipe and weld joints at both mufflers.
No leak found.

I checked at the branches as well, couldnt see any leak.

Tomorrow im stripping the interior out to install the deadening pads. Using Dr Artex Iridium Medium pads.

I am hoping this will help.

 

[Bl4d3]

So I did some digging around online and I think I might have found the cause but no way to actually test.
The engine mount under the intake filter box.
This would make sense because at idle the car vibrates terribly (sometimes) and even worse when the A/C is on.

 

[Gobinator98]

So I did some digging around online and I think I might have found the cause but no way to actually test.
The engine mount under the intake filter box.
This would make sense because at idle the car vibrates terribly (sometimes) and even worse when the A/C is on.

Best way to check the mount is to put a jack under the oil pan and jack up. Don’t forget to put a wide piece of wood or something to prevent damaging the pan. If the whole car moves when jacking up, then the mount is good. If the car doesn’t and the motor only moves up, the mount is bad.


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[Bl4d3]

Before checking the mount I decided to check the spark plug gaps.

The idiots who did my previous service gapped them to 0.050inch. I've gapped them with a decent feeler gauge to 0.030inch. I'm hoping this is once of the reasons for the engine running loudly.

 

[Bl4d3]

So I gapped the plugs and finished putting together the entire interior, the horrible vibrations at idle and low revs are gone and the car feels a bit more responsive however the is still a loud drone at 120km/h / 75mph.

Any other ideas?

 

[Gobinator98]

So I gapped the plugs and finished putting together the entire interior, the horrible vibrations at idle and low revs are gone and the car feels a bit more responsive however the is still a loud drone at 120km/h / 75mph.

Any other ideas?

I don’t have any ideas besides that it could be something with your wheels and their alignment/balancing.


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[Bl4d3]

I don’t have any ideas besides that it could be something with your wheels and their alignment/balancing.


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Honestly, that wouldn't surprise me. I bought the car used and still has the same tyres on that I bought it with, all 4 tyres are different brands and I probably need to change it within the next 10000km.
Granted with it being the festive season and after just throwing a boat load of cash at the sound deadener, I will have to retire that for a later stage.

Thanks for the help otherwise, at least we managed to make the car some what better

 

[Bl4d3]

So the vibrations came back shortly after I gapped the spark plugs, murphy's law I think.

Started digging further and realized that my car is 8 years old with 100000km on them, it probably needs replacement engine mounts.

Purchased the one I think is causing the problem and will fit later tonight. The rest of the mounts are ridiculously overpriced at the GM Agent for some odd reason.

The dog bone mount I can get in the US with freight for $47.00 (OEM) while the local GM Agent is charging $130.00

 

[Bl4d3]

So loosened the mount, then realized that I need a deep socket to get the 1 nut off.
Literally the only tools I dont have is deep sockets.

Nevertheless, I decided to loosen as far as I could to see the condition of the mount, its completely shot so I think thats the culprit

 

[Bl4d3]

Replaced the engine mount today after I got a 15mm deep socket.
The car is whisper quiet now