Yesterday I noticed that my 2.8Q sounded louder than usual. Upon initially starting the car, It sounded louder than my E36 BMW. I checked the oil level and it seemed normal. I figured it was probably because it was cold that morning. I did let the car warm up a few minutes to see if the noise would go away. It didn't! So I decided to call my hubby to come out to see what he thought of it. He said that it sounds like an exhaust leak as whenever I revved the engine, the noise would emanated between the Cats and the headers. He looked to see if he could find something but he couldn't.

We drove around the block and he quickly noticed the car "popping" during deceleration. Almost like backfiring but the popping noises sounded like it was coming from under the car near where the engine and transmission meet. My hubby says that he could also feel the popping noises very slightly when he drove the car. So he says it's confirmed, a leak in the exhaust system is the culprit! My question is, where would it usually leak from?

I took it to a muffler shop but I was kinds iffy of what they says the problem was. The shop said that it was the header that was leaking but the noise is more pronounced from underneath the car rather than from the engine bay. Could it be the dreaded flex hose? Advice needed please!

Thanks in advance everyone and have a wonderful day!

 

My wife complained about the same on her 2.8Q and this is what I found out.

Air Intake - it has two modes summer and winter. During summer time the air is drawn from in front of the car so you do not hear anything. When the temperature changes there is a flap that opens in the air intake system and it draws hot air from the engine compartment. The difference is that in the second scenario you will hear this noise as at the begining of cold weather it half opens both air ducts. When the temperature drops to minus 10 only the hot air intake is opened and the noise stops.

 

On mine, it definitely sounds like an exhaust leak. Unless what you described is reminiscent of a what I have described in my previous post. Also, would the intake flap thingy generated popping noise during engine braking/deceleration?

 

One thing with ehaust leak is that you can definitely smell it. If your temperature is around zero than I say your air intake is cofused right now is it winter or summer? I would use air intake cleaner on it or wd40. Just spay inside. It may give you some popping sound during deceleration when engine is cold.

 

Don't spray wd40 into your intake. You will stall your engine. Also, the flap he is referring to does not open in cold weather, it is a failsafe in case the front becomes blocked, so that air can still enter the intake. Your problem is with your exhaust, not intake, and Adam is an Internet troll.
When the flex pipe on my B5 2.8 went, my car sounded like a tractor.
If you have doubts, go to another shop and get a second opinion.

 

In my experience, not all exhaust leaks emit an aroma especially if the leak is located closely towards the end of the exhaust system. Unless you want to ruin your MAF and it's sensors, I would not recommend spraying WD40 or the likes into the intake! The "popping noise" is clearly emanating from underneath the vehicle, just behind the bulkhead.

Hi Jordon, what part of the flex pipe did you actually have to repair/replace? Are there ways to delete the flex pipe and possibly install a solid tubing in its place? I am waiting for our mechanic to come back from his holidays to perform an actual diagnosis of the problem.

 

The metal mesh part became separated at the shop when they were driving it onto the ramps for the hoist (I had to fight with them to get them to fix it on their own dollar). They simply welded in a new section where it separated. I think you should avoid replacing it with solid pipe. I think that the whole point is that it needs to have some flex in that section.
Another thing to maybe check, is the catalytic converter. Perhaps the cat is becoming plugged, or maybe the catalyst is breaking apart.... Did you trigger a CEL? Any codes? If not, cat will be unlikely.

 

Double post
sorry

 

The CEL is not illuminated but I have not checked for codes yet.

 

If you have flaps - than you have hinges.
I keep mine lubricated at all times, furthermore I keep my K&N filter moist with lubricant at all times. I never ruined any sensors and I found out that it makes the car react much sooner.
In my case it was one of the flaps that stalled and needed wd.

WD WORKS FOR ME!

The exhaust leak is very unlikely yet possible.