This car has been nothing but problems ever since I bought it 5 years ago. Okay, so when the car is idling, the boost gauge now sits slightly above -20, whereas before it would be below 20. It also boosts around 5-7psi unless I bring it to redline which in that case it's lucky to go past 10psi.

I had our family mechanic inspect it, and he even removed and re-sealed the supercharger to intake manifold gasket which did absolutely nothing. There aren't any exhaust leaks, and the down pipe has like 10,000 miles on it (was replaced under recall).

I don't understand. It has to be a vacuum leak, but where? It sounds like its coming from the middle or passenger side of the car, almost like where the blower motor is.

Anybody familiar with this problem? It's driving me insane how I can't even go a month without something failing on this thing. It's ridiculous and I am sick and tired of dealerships giving me the runaround when all I want is to get another year or two out of this thing before I make another new car purchase.

HELP!

 

Hissing - YouTube

Exhaust leak? The down pipe was replaced 10,000 miles ago!

 

u could have broken the flex part of the dp.. idk if this would happen on cobalts but i once had n eclipse that made the hissing sound cuz of a cracked header... i would check the gasket also

 

If thats whats broken i would get a header and downpipe. Sounds like thats your problem.

 

I sprayed soapy water on the flex section when it was cold and didn't see anything. I don't know about the header though...does anybody know where they usually crack?

This is the most annoying car in the world when it comes to exhaust problems.

 

remove the header heatshield and look in between them

 

I don't even have the heat shield on haha. I can't see anything resembling a crack.

 

cracks are really hard to see when its bolted on, i noticed after i took it off lol

 

Where on the manifold did yours crack? Did it sound like mine does in the video?

 

in between 2 of the pipes where they meet, mine sounded like hissing when i stepped on it

 

Yeeuup, I can vouch for ya when it comes to exhaust leaks, OMG it took me seriously like 7-9 months to finally have a Tech figure out where and how to fix my exhaust leak issues Its finally fixed now(touching wood) and its much better and hopefully it stays that way!

 

crack in the flex wouldn't be noticeable at idle unless it was big enough to see on itself lol. mine made a hissing only under boost sounded like a wimpy ass t/c.

 

so u went eith GMP clutch after all huh? lol

 

I just ordered a BadMab header, it was like 200 bucks. If this doesn't fix it then I am going to drive the car off a cliff.

 

It's terrible. I hate driving it because it sounds so stupid

 

Mine does hiss only under boost, at least thats where it becomes most noticeable from the cabin. I'm about to order a new down pipe now too lmao

 

ya that accordian flex pipe is worthless

 

Yeeuup, I Love it, It has that Stock Feel to it and yet it engages much better and can actually handle the load.

Haha, I know LMAO

 

i havent heard any bad things about that clutch, still cant believe its cheap

 

I just ordered the 2.5" ZZP down pipe as well. With my luck that POS accordion will fail next... haha

 

the flex part breaks most of the time thanks to our sucky mounts... do a nice downshift or take off and it will be enough lol

 

lol yeah, junk.

I just ordered a BadMab header, ZZP downpipe, and remflex gaskets for the mani-DP and DP-catback. If this thing hisses I am going to ghost ride it into a concrete wall

 

part out? lol

 

I'll have to make sure nothing is broken first. With my luck it's probably just a gasket thats burned out lol

 

The boost gauge went to 15psi at WOT, so that works lol.

I think the problem is the gasket between the manifold and the down pipe. When I replaced the down pipe, I used two gaskets because the one GM gasket wouldn't seal properly (must be warped a bit). Two helped, but under boost the pressure probably forces some air between the two gasket surfaces. I have a Remflex gasket sitting in my desk drawer that I am going to try.

It's done this ever since I replaced the downpipe several months ago. I'd think if the flex pipe had a hole in it then it would have gotten a lot worse and probably split by now.