Exhaust (Corsa) banging on Drive Shaft

**trukk** · 03-30-05 02:02 PM

I need some help on this.

So i'm driving back from Virginia to MD on Monday, during a 'monsoon'. All was well until I hit a fairly large puddle (say 20 feet long, 1.5" deep).

Then BANG BANG BANG BANG. It sounded like a rabid monkey was banging on the under side of my car with a crecent wrench. Scared the crap out of me. It kept going untill I managed to pull over to the side of the road a few hundred feet later (damn VA and their no shoulder rural ass highways).

I pulled over, and the noise stopped. It was really raining hard (I said monsoon), so I didn't get out to look under the car, as I still had 4+ hours of rainy holiday weekend traffic driving to go, and didn't want to be soaked to the bone. I slowed reved the engine in nuetral, and no banging at all, what so ever. This really relieved me. I slowly drove around the parking lot, no noise. I did a tight circle, and slowly picked up speed, and no noise. At this point I was hopping that I just picked up some debris under the car, that fell out when I stopped.

I drove on, and hit another smaller puddle (monsoon remember), and again, BANG BANG BANG. Pulled over, stoped, and started up again, no BANGING. At this point I new I had to take a look at this, figuring it was either driveshaft against the tunnel, or resonator against driveshaft ( sound was comming from directly under the center arm rest).

After a few more miles, and drove through a podunk 'town' that had a drive up carwash stall. I pulled in, and was able to get some protection from the rain (monsoon, I said that already right?), and looked under the car. Sure enough, the passenger side of the Corsa resonator was hanging down about 15 degrees. ARGH, the resonator must be bouncing off the drive shaft. I pulled out, and went hunting for a service station (yeah NAV system).

The closest service station, was Goobers in Mayberry RFD. After a 15 minute wait, I explained my symptoms to Goober, and he indicated that I had an exhaust leak, and would look at it. Another 10 minutes, and he came back and said I had no exhaust leak, and couldn't beleive it was making a 'banging' sound. I then told him that the resonator was hanging funny, and that must have something to do with it. He then told me "Boy, I told you there was nothin' wrong with that exhaust." Ahhuh. So I asked him what I owed him for his trouble. He says "Boy, I didn't do nothin' for you." No $h!t, I thanked him and went on my way, before he started complimenting me on my purty lips (Damn you NAV system).

I drove on a bit more, with another banging session a bit later, when the monsoon resumed. I finally found a place named "Southern Muffler", and pulled in there, as I knew I had a long way to go, and didn't want to trash something on my car. This was the cleanest shop I have ever been in, the HUGE service bay looked like an operating room. They quickly put my car up on a lift, and immediately diagnosed the problem (they allowed me to have a look also). The driver side of the Corsa was actually to high, and the pipe right behind the resonator, was hitting the drive shft (actually it was hitting a balance weight on the shaft, hence the ocilating banging sound, rather than a scraping sound). The driveshaft weight was a bit scraped, as was the pipe, but nothing too bad. They loosened everything up, and repositioned it, to level out the resonator. $24 dolars later, I was on my way, happy and content.

All was well again...untill I made it to Alexandria, where enough rain had fallen, that it almost had as much in common geographically with it's egyptian namesake. I hit another large puddle, and BANG BANG BANG. It just happened that one time.

I made it home, and took a look at it yesterday. There was about 3/8ths of an inch between the drive-side pipe, and the driveshaft at it's closest point. My dealer never gave me the corsa install instructions, so I don't know if this is within tolerance according to them or not.

The puddle thing is what has me perplexed. Is that enough force to 'push' the exhaust into the DS? Or perhaps the cooling affect of the water causes the metal to contract (this sounds highly doubtful). Is this somehow related to the driveshft, and not an exhaust problem at all? Is the dual shaft DS and the 'soft' rubber busings an issue, allowing enough of an ocisllation that it hits the exhaust?

Any help and/or advise is requested.

If anyone ahs the Corsa Install instructions in digital, please PM me, I would like to take a look at these.

Thanks,

Chris

**6104696** · 03-30-05 02:17 PM

Originally Posted by trukk

I need some help on this.

So i'm driving back from Virginia to MD on Monday, during a 'monsoon'. All was well until I hit a fairly large puddle (say 20 feet long, 1.5" deep).

Then BANG BANG BANG BANG. It sounded like a rabid monkey was banging on the under side of my car with a crecent wrench. Scared the crap out of me. It kept going untill I managed to pull over to the side of the road a few hundred feet later (damn VA and their no shoulder rural ass highways).

I pulled over, and the noise stopped. It was really raining hard (I said monsoon), so I didn't get out to look under the car, as I still had 4+ hours of rainy holiday weekend traffic driving to go, and didn't want to be soaked to the bone. I slowed reved the engine in nuetral, and no banging at all, what so ever. This really relieved me. I slowly drove around the parking lot, no noise. I did a tight circle, and slowly picked up speed, and no noise. At this point I was hopping that I just picked up some debris under the car, that fell out when I stopped.

I drove on, and hit another smaller puddle (monsoon remember), and again, BANG BANG BANG. Pulled over, stoped, and started up again, no BANGING. At this point I new I had to take a look at this, figuring it was either driveshaft against the tunnel, or resonator against driveshaft ( sound was comming from directly under the center arm rest).

After a few more miles, and drove through a podunk 'town' that had a drive up carwash stall. I pulled in, and was able to get some protection from the rain (monsoon, I said that already right?), and looked under the car. Sure enough, the passenger side of the Corsa resonator was hanging down about 15 degrees. ARGH, the resonator must be bouncing off the drive shaft. I pulled out, and went hunting for a service station (yeah NAV system).

The closest service station, was Goobers in Mayberry RFD. After a 15 minute wait, I explained my symptoms to Goober, and he indicated that I had an exhaust leak, and would look at it. Another 10 minutes, and he came back and said I had no exhaust leak, and couldn't beleive it was making a 'banging' sound. I then told him that the resonator was hanging funny, and that must have something to do with it. He then told me "Boy, I told you there was nothin' wrong with that exhaust." Ahhuh. So I asked him what I owed him for his trouble. He says "Boy, I didn't do nothin' for you." No $h!t, I thanked him and went on my way, before he started complimenting me on my purty lips (Damn you NAV system).

I drove on a bit more, with another banging session a bit later, when the monsoon resumed. I finally found a place named "Southern Muffler", and pulled in there, as I knew I had a long way to go, and didn't want to trash something on my car. This was the cleanest shop I have ever been in, the HUGE service bay looked like an operating room. They quickly put my car up on a lift, and immediately diagnosed the problem (they allowed me to have a look also). The driver side of the Corsa was actually to high, and the pipe right behind the resonator, was hitting the drive shft (actually it was hitting a balance weight on the shaft, hence the ocilating banging sound, rather than a scraping sound). The driveshaft weight was a bit scraped, as was the pipe, but nothing too bad. They loosened everything up, and repositioned it, to level out the resonator. $24 dolars later, I was on my way, happy and content.

All was well again...untill I made it to Alexandria, where enough rain had fallen, that it almost had as much in common geographically with it's egyptian namesake. I hit another large puddle, and BANG BANG BANG. It just happened that one time.

I made it home, and took a look at it yesterday. There was about 3/8ths of an inch between the drive-side pipe, and the driveshaft at it's closest point. My dealer never gave me the corsa install instructions, so I don't know if this is within tolerance according to them or not.

The puddle thing is what has me perplexed. Is that enough force to 'push' the exhaust into the DS? Or perhaps the cooling affect of the water causes the metal to contract (this sounds highly doubtful). Is this somehow related to the driveshft, and not an exhaust problem at all? Is the dual shaft DS and the 'soft' rubber busings an issue, allowing enough of an ocisllation that it hits the exhaust?

Any help and/or advise is requested.

If anyone ahs the Corsa Install instructions in digital, please PM me, I would like to take a look at these.

Thanks,

Chris

Chris:

well written; thanks for the laugh.

You can get the corsa instructions from their website at Corsperf.com. 3/8 of an inch is normal (at least I have the same amount or maybe less) at that point. Did you have your dealer retorque the Corsa after a week? If not, then something may have moved. Yeah, IMO a huge puddle could have cuased sudden and uneven cooling of a part of the system, resulting in some movement. There is a LOT of heat expansion on this system. My pipes grow at least a half inch in length as they heat up (oh, my, did I just type that?), so a sudden splash of water might cause some twisting. If the connections are not tight then they might twist a bit.

The Corsa insturctions are very clear about the need for a retorque; and hving done it, I put a few cranks with the torque wrench to bring the clamps back up to 40 pounds. Somebody (it may have been Corsa) had indicated to me that 50 pounds is good too. Since I hate breaking bolts, I stuck with 40.

There are a lot of close tolerances in this system. Mine is quiet as a mouse, except for last week I hit two jarring bumps on an interstate at high speed and I thought I heard an isolated clang. I suspected that either the area near the resonator hit the driveshaft or perhaps the muffler inlets hit the anti-sway bar. I have not checked it out yet, as it was such an isolated incident.

If this was dealer installed then bring it back to them......

Doug

**FastVee** · 03-30-05 04:36 PM

Yes, if the dealer did the install..their responsible. I installed mine,I did notice on my first try that the Corsa was very close to the driveshaft... all you do is loosen the 4 clamps up front. It will drop, then retighten them to your liking. BTW, my clearance is about an inch.

**6104696** · 03-30-05 04:49 PM

Originally Posted by FastVee

Yes, if the dealer did the install..their responsible. I installed mine,I did notice on my first try that the Corsa was very close to the driveshaft... all you do is loosen the 4 clamps up front. It will drop, then retighten them to your liking. BTW, my clearance is about an inch.

Do you mean the 4 Torca clamps that are at the front and back of the resonator, or the 4 flange bolts securing the front Corsa pipes to the factory cat outlet flanges? I have considered getting back under it to try to gain more clearance but it's been essentially clang-free and I've been lazy. I figured I would need to loosen everything. Last week's clang made me reconsider.

Doug

**lasstss** · 03-30-05 05:09 PM

Originally Posted by 6104696

Do you mean the 4 Torca clamps that are at the front and back of the resonator, or the 4 flange bolts securing the front Corsa pipes to the factory cat outlet flanges? I have considered getting back under it to try to gain more clearance but it's been essentially clang-free and I've been lazy. I figured I would need to loosen everything. Last week's clang made me reconsider.

Doug

My corsa system was flexing. The joints slip. You need to really crank the clamps down to keep the system from moving. I will be welding the joints soon.
Good thing about the B&B is that it stays put.

**CVP33** · 03-30-05 05:25 PM

LASSTSS,

I agree. I've done a number of fluid changes and everytime I do I've gone to re-tighten all the BB connectors etc. only to find they are as tight as I can physically make them. Nice to have a quality product. Now about that header group purchase................