A couple weeks ago I decided to make some adjustments on my Milltek catback so it’s centered in the rear valance opening and in doing so I had to loosen up the flanges and damaged the front flange to where I had a very slight exhaust leak and I mean slight. Well it had to go in to the body shop and just picked it up yesterday and decided last night to replace the gaskets which I did however now it sounds like a diesel from the engine compartment. I thought it blew out the manifold gasket so I completely removed the manifold and didn’t see anything wrong. The manifold bolts came out without any trouble to my surprise and went ahead and ordered a Milltek header today since it’s already out. But my question is I’ve never heard a exhaust leak sounding that way. Is that normal if it was leaking at the manifold flange? I don’t think it’s sc related because it was more in the rear then I thought maybe valvetrain issues so I removed the valve cover and looks good in there so I’m hoping it was a gasket leaking.

 

The cat after the header tubes are a common area, where the pipe breaks off. You can get it re-welded, if that is all you need.

 

There’s a small pre cat before the main cat that’s looks to be repaired once before and looks hideous it’s that bad. I couldn’t tell if it was coming from that or not just behind the engine.

 

This isn’t normal right? To me it looks to b repaired at one time??

 

That is a butcher job at best and I don't doubt that is your leak!

 

Lol you think I could have a restriction there? Always wondered why my other MCS is so much fast with the identical mods. We’ll see what happens Monday when my Miltek header shows up.

 

Well the new pipe showed up today and excited to get it in. Wow what a difference!!

 

Yikes. wow never seen that before.

 

Well, that's one ugly-*** weld! My pre-cat cracked there and I welded the repair like this. Except better :D

 

Well got it installed and started up the car and the so called "exhaust leak" is still there. After further looking into it it turned out to be a bad timing chain tensioner. So my $800 header replacement really all that was needed was only a $40 part. Oh well live and learn but it's a very high quality header and the fitment was excellent. Haven't had a chance to drive it yet because I went ahead and removed the chain tensioner. So we'll see in a few days.

 

The new headers look good. I just picked up a 2005 yesterday that has an exhaust leak. Is it difficult to get the manifold out? I am going to try it this weekend just not sure what I'm in for on it.

Also, you should post a video of the sound of the new headers!

 

No it was very easy. It comes out from the bottom and you will have to remove the driver's side tunnel heat shield them turn the manifold as you're lowering it down and out to clear the gear shifter cables. That's after you unbolt the exhaust pipe. I unplugged the o2 sensors and removed them with the pipe. The down stream one was a pain because it's up above the brake lines and it will come out with the black plastic bracket. The upper heat shield comes out from up above. It's a good idea to disconnect the battery just don't shut the boot or hatch after you do so.

 

While you have it out, you may want to check for leaks around the Oil Filter Housing and the Oil cooler. So much easier to replace with the manifold out of the way...

 

Is that a common oil leak area? How many gaskets / o-rings / etc are involved?

 

There are two oval o rings for the oil cooler and one seal for the filter assembly.

 

This is good info. When. I pull mine I'll check it out.