Growling 07 Focus engine???

[Lolvoguy]

Got me another problem with my 07 Sedan (in sig).

When I start the car, it's far noisier than it used to be. Kinda like the air intake snorkel is now the muffer...if that makes any sense.

I've replaced the pass side mount with a Ford one, and the car was very quiet (mostly noticed less vibrations).

But now the vibrations are still relatively smooth, but the engine sounds like I have an exhaust leak.

Anyone know what it might be? I recall hearing problems with the Duratek tumble flaps on the intake (not sure if that makes sense). I also replace the one mount about 1 year and 10k miles ago, so I don't think it's failed again considering the original Ford one lasted much longer.

help appreciated

 

[SatinSilver]

It may just do that in the cold weather on a cold start. The 05 Matrix has done this for the last few years. Then goes away when the weather warms up.

 

[mclasser]

Is it noisier when warmed up, too? I'd think an exhaust leak would cause a racket at all times.

 

[Linctex]

Time for a cheesy "ricer" Cold air intake!

Have you examined the interior of the induction system for condition & structural integrity?


Don't rule out an exhaust leak.... they can be very hard to locate.

 

[eljefino]

Stuff a rag in your muffler and try to hold it back when you idle. If your exhaust is tight it will blow out in your hand. If it has a leak, you'll hear it.

 

[KrisZ]

Could be an exhaust shield, the little steel nuts seem to corrode and take aluminum around them as well over time. I used big washers with success to fasten back the rattling heat shields.

 

[Lolvoguy]

Afer thinking about the 97 Escort we had years ago that developed the same noise, I was almost certain it was the flex pipe that developed a leak. So I decided to take a look today.

Jacked up the front of the car and took some pics with my phone to see if there was any blackened areas on the flex portion which would indicate a leak. Nope.

Considering the garage is cold, and exhaust gasses are easily visible from the tail pipe I decided to start it with the car in the air. No visible leaks either. I also didn't feel any air being forced out with my hand around the flex section.

What I did notice was that the noise was most pronounced in the resonator area which is after the cat, but before the rear muffler. The rear of the car is almost dead silent. It's just this one area which I speculate is causing the noise (the resonator).

The order of exhaust is:
Header>>Cat>>flex pipe>>resonator>>>>muffler

Is this a common failure piece on the Focus? I've never had one fail on me before...really sounds like a bad muffler but with the noise near the engine area (no outer rusting/punctures were present).

thanks in advance

 

[Lolvoguy]

Yup, turned out to be the flex pipe as expected