lowing/whistling noise from exhaust

[m3f_Deo]

Hey guys, Before you tell me to use the search function i'd like to just get it out of the way now and tell you I have. Nothing that really helps has come up. That said let me try and explain my issue.



Under acceleration I find the exhaust makes a blow/whistling noise. You can hear it a little bit on open roads, but it is very easy to hear when you are driving beside a median. Reminds me of an old beat up corolla exhaust as the car just putts along. As of right now i'm thinking this is an exhaust leak. I asked a friend to stand on the side of the road while I drove by and put my foot down, he said it sounds like it is coming from the middle. When the car is in neutral however, and I let it idle or rev it, you cannot hear it at all. That makes me question my diagnosis somewhat. In any case, does anyone have any advice as to how to test for what this is, and fix it? I thought if it was an exhaust leak I could put it up on stands, put soapy water on the pipes, start it up and run through the gears, but that seems highly unsafe. Anyway, any help would be greatly appreciated!

[m3f_enderw88]

Put it up on stands and visually inspect the exhaust system, especially the joints. The engine doesn't pump much air unless it is under load, so a check neutral may not tell you anything. Do you know if it is OEM exhaust?

[m3f_Deo]

Put it up on stands and visually inspect the exhaust system, especially the joints. The engine doesn't pump much air unless it is under load, so a check neutral may not tell you anything. Do you know if it is OEM exhaust?

The exhaust is OEM. When I put it up, how will I tell if there is a problem with the joints? Would I have the car running at the time and feel it coming out of a spot? I can't imagine its safe to engage a gear and have the tires moving while its in the air. You pretty much only hear it when you give it some gas, like when going through the gear to get up to speed.

[m3f_enderw88]

The exhaust is OEM. When I put it up, how will I tell if there is a problem with the joints? Would I have the car running at the time and feel it coming out of a spot? I can't imagine its safe to engage a gear and have the tires moving while its in the air. You pretty much only hear it when you give it some gas, like when going through the gear to get up to speed.

No, I wouldn't have the car running, and I wouldn't even have it hot. Just LOOK for holes, and check the joints for tightness. If you don't find anything, then its time for more extreme measures.

[m3f_Deo]

No, I wouldn't have the car running, and I wouldn't even have it hot. Just LOOK for holes, and check the joints for tightness. If you don't find anything, then its time for more extreme measures.

Thanks Enderw, assuming I can't find anything. What would be my next step?

[m3f_enderw88]

Thanks Enderw, assuming I can't find anything. What would be my next step?

Try to post a recording of the sound.


It also struck me, that while you are under the car, to look at the insulation blanket and make sure that it isn't hanging down and rubbing on the drive shaft. It should be obvious, there will be a nice silver ring on the driveshaft where the blanket has been rubbing on it.


Craig

[m3f_hencini]

You can have the car running on jack stands, no problem. I did it just the other day to check for leaks after I installed my Stromung. Hell, you can even have it in gear, but I wouldn't get under it with the tires spinning. Either way, just make damn sure your jack stands are secure. Wouldn't want to exit the gene pool because you were trying to do this with a spare tire jack. :Goodluck:

[m3f_enderw88]

You can have the car running on jack stands, no problem. I did it just the other day to check for leaks after I installed my Stromung. Hell, you can even have it in gear, but I wouldn't get under it with the tires spinning. Either way, just make damn sure your jack stands are secure. Wouldn't want to exit the gene pool because you were trying to do this with a spare tire jack. :Goodluck:

If you are going to be under the car while it is running, make sure the area is very well ventilated. If you have an exhaust leak under the car and you are there poking around you could be overwhelmed by CO fumes rather quickly. If I had to do this I would set up a good fan to blow beneath the car, and do it outside.

[m3f_RickO1]

You might be able to replicate the problem by trying to partially blocked the tailpipes. If it is leaking someplace, that would force it to exit in that area. Just be sure to use some very thick padding or gloves. It will get hot very quickly.

[m3f_enderw88]

You might be able to replicate the problem by trying to partially blocked the tailpipes. If it is leaking someplace, that would force it to exit in that area. Just be sure to use some very thick padding or gloves. It will get hot very quickly.

Possibly even easier would be to Seafoam the engine intake then look for smoke exiting where it shouldn't...and you cleaned the engine internals as well...

[m3f_RickO1]

Possibly even easier would be to Seafoam the engine intake then look for smoke exiting where it shouldn't...and you cleaned the engine internals as well...

This was going to be my second suggestion...honest.

[m3f_enderw88]

This was going to be my second suggestion...honest.

[m3f_Deo]

Here's a video of the sound i'm hearing. I couldn't find the source. I went under the car, felt around, started it and look and smelt around. Nothing.



M3 Exhaust leak? - YouTube











M3 Exhaust leak? - YouTube

[m3f_enderw88]

Umm, I don't hear anything unusual there. It doesn't sound like an OEM exhaust, what is it running?

[m3f_M3n00b]

Umm, I don't hear anything unusual there. It doesn't sound like an OEM exhaust, what is it running?

I think that's the point....