Got my Cobalt SS sedan and its making the wierdest noise! After start up when its still cold I get 3 knocks, knock knock knock, from the gas cap? Give it another minute or so
knock knock only 2 this time and finialy in a few more just 1 knock.

The first time we heard it my daughter and I thought someone was knocking on the side of the car so we looked around and no one was there so we dismissed it. Then it did it again.

Does anyone have idea what on Earth this is?

 

yea alot of cobalts do that i dont know if anyone has fig out what it is... but i know i get the same 3 knocks but i cant seem to fig out what it is

 

it's normal... i've heard it a few times too....

 

Its not like I think the car is gonna explode its just I'm curious as to what it is.

I asked the guys here at work (dealership) and all I get is the deer caught in headlights look.

Oh well thanks guys.

 

mine does it too, and no clue why

 

search and you will find the answer

 

there IS a technical answer floating around somewhere... i think it was something like exhaust gasses or something like that... i don't remember what it was though...

 

Guys it's just your gas tank checking it's fuel pressure to make sure there are no leaks. That's all it is. It's 100% normal.

 

it's the exhaust system....it is normal to make noise when it is cooling off. Something having to do with the hot metal cooling off . Nothing to worry about.....they all do it. It's commonly referred to as the cobalt ghost....lol

 

The trunk latch will also do self tests from time to time - you may be hearing that...

 

He's talking about when it's cold. It's the old 3 knock. Like I said it's just your car checking it's fuel pressure that's all it is.

 

ya my 97 grand am does that as well

 

reading comprehension > me......lol

 

Cool thanks man!

On start up..... not cool down.

The trunk lock you say? Thats odd but Ok I guess its possible.

I was just wondering what it could be guys thanks.

 

See I didn't want to put it that way cause I didn't want it to be taken as me flaming you.
But I was thinking it !!

 

Not a problem bro.

It's all good there sweets. I do it all the time. With the thousands of threads we read all day i'm surprised we don't do it more often.

 

hey atleast I admit it....if you would have just called me a dumb a** and moved on, I wold have respected that...lol...probably not. I'd have to flame you for not using the search button....lol

 

I see no "search" button on my keyboard, where do I get one?

JK guys!

 

^^ lol you're not the only one

 

LMAO!!!!