Engine Noise (Page 2/3) A_Lonely_Potato MAY 02, 03:37 PM quote Originally posted by Patrick: Difficult to tell from a video, but it sounds to me like an exhaust leak. Check to make sure that all exhaust manifold bolts are actually in place. I wouldn't be surprised if you discover that the forward exhaust manifold is cracked. Funny thing, about a week ago my engine started making the same noise, although less severe. Just last night as I was pulling out of McDanks I heard a pop and everything got VERY loud. Turns out my Y pipe developed a hole, looks like right at the seam. I pulled over immediately and checked the manifolds and other areas that could be a problem, everything looked fine though. Started the car again and was trying to listen around when I noticed a bif of fiverglass wrap on the Y pipe was flapping in tune with the noise. Car is insanely loud now, feel the noise in the seat, gas pedal, steering wheel, etc. Gonna weld it up today, maybe after a quick spin for my own ear pleasure.... Patrick MAY 02, 05:27 PM quote Originally posted by A_Lonely_Potato: I noticed a bif of fiverglass wrap on the Y pipe was flapping in tune with the noise. Yeah, heat shields and/or fiberglass wrap can do a "good" job of hiding cracks in the Y-pipe and/or in the flexible EGR tube. nero MAY 02, 09:09 PM quote Originally posted by Patrick: Yeah, heat shields and/or fiberglass wrap can do a "good" job of hiding cracks in the Y-pipe and/or in the flexible EGR tube. Funny you say that, I spent most of my night to get 1 rounded off rusty nut loosened up on the heat shield on the front facing manifold. The other nut tomorrow night, but that one looks in much better shape.From what I see the manifold looks in good shape but I think I see some black soot near a few of the manifold runs on the gasket. Hard to tell for sure if its just the gasket falling apart or soot on the gasket from the manifold leaking but trying to get a better look by removing the heat shield. Its still hard to get a really good look back there so after I get the heat shield off I still can't get a good look, I am going to take the y pipe after and then put my cheap inspection camera into the manifold which has a light so I should be able to see any light shining through the mating surface or where there are any cracks. Patrick MAY 02, 09:44 PM quote Originally posted by nero: ...the heat shield on the front facing manifold. I had forgotten about that particular shield. When I ported my exhaust manifolds, I didn't bother reinstalling it. I believe it was placed there during one of the recalls. There seemed to be a general consensus here that it was next to useless, and only increased the probability of an exhaust leak on that forward bank. nero MAY 03, 08:16 PM Thanks for the heads up on the heat shield Patrick quote Originally posted by Patrick: I had forgotten about that particular shield. When I ported my exhaust manifolds, I didn't bother reinstalling it. I believe it was placed there during one of the recalls. There seemed to be a general consensus here that it was next to useless, and only increased the probability of an exhaust leak on that forward bank. nero MAY 03, 08:29 PM So I discovered I have exhaust leaks at the Y pipe and at the front facing manifold. The Y pipe comes apart nice and easy but some of the nuts look pretty rusty on the exhaust manifold, so does not look fun. I will probably give it a try and if a stud snaps off, not sure what I will do at that point. In any case, below is a video I found on Youtube on how to easily find exhaust leaks (non Fiero related). Do not need the car running, you just need a shop vac and some tape and a a cloth or two and some soapy water. It works really good but unfortunately gave me definitive proof of what I did not want to know that the front facing exhaust manifold was leaking. https://www.youtube.com/watch?v=l09cp5DBTjk Patrick MAY 03, 11:05 PM quote Originally posted by nero: ...if a stud snaps off, not sure what I will do at that point. Look for a bridge, a high one. nero MAY 04, 04:55 PM Lol, too funny. Before I do that it will be a loud series of curse words, followed by several tools being flung across my garage floor. Off I go to start the 'fun'. quote Originally posted by Patrick: Look for a bridge, a high one. nero MAY 04, 07:25 PM Well the car gods were good to me tonight. It was not the first time the exhaust manifold had been off. 3 of the nuts were just short of hand tight, the other ones were not too bad to get moving although the whole stud came out on one of them instead of just the nut.. There was already 1 stud that was replaced and it was replaced with an oversized stud. Picture below shows the enlarged hole on the manifold. It looks like only 1 of the 3 exhaust ports were anywhere near sealed. I also discovered that the end of the manifold where it connects to the y pipe is shaped like an egg. I assume this is not the shape it should be based on how the y pipe is shaped. So that explains the leak at the Y pipe connection. So I am on the hunt for a front facing manifold if anyone has one. I will also try out the mall. Patrick MAY 04, 08:32 PM quote Originally posted by nero: So I am on the hunt for a front facing manifold if anyone has one. I will also try out the mall. With that being the one that usually cracks, finding a replacement will be a bit more of a challenge. If you think your luck removing manifold bolts might continue, you should also remove the rear exhaust manifold so that you can port both manifolds. The exhaust will sound and flow better. It's good for a few extra ponies.