Rattling Noise Only at low rpm when transmission is in gear

[RandallNeighbour]

Jack the car up and put it on jack stands in the back. Get on your back and get under the car, and bring a hammer with you.

The metal heat shields on the cats make the exact sound you all are describing.

Hit the living crap out of the loose heat shield to bend it a little and tighten it up. This will feel really good if you are as pissed off as I was with that rattle buzz noises at low speeds in low gears in alley ways or by fencing.

Then get the car back out on the road near a fence and you won't hear it any longer. You will feel the satisfaction of knowing you beat your Porsche with a hammer and that's exactly what it needed and what your mechanic would have done, but charged you for it.

[David Wildrick]

Originally Posted by RandallNeighbour

Jack the car up and put it on jack stands in the back. Get on your back and get under the car, and bring a hammer with you.

The metal heat shields on the cats make the exact sound you all are describing.

Hit the living crap out of the loose heat shield to bend it a little and tighten it up. This will feel really good if you are as pissed off as I was with that rattle buzz noises at low speeds in low gears in alley ways or by fencing.

Then get the car back out on the road near a fence and you won't hear it any longer. You will feel the satisfaction of knowing you beat your Porsche with a hammer and that's exactly what it needed and what your mechanic would have done, but charged you for it.

I checked out what I thought was a crack in the exhaust system last night and took a photo of it. But after probing the "crack" with a screwdriver and high intensity light, I realized it was just a gap between where the bracket for the cat converter is welded to the converter and the endcap of the converter. This gap is much deeper on the right side than what is seen on the left side of the car.
In the attached pic, the bogus "crack" is denoted by arrow #1.



Randall,
Does my arrow #2 point to the metal heat shield you refer to? Or is it even visible in this photo? Thanks.

[yimmy149]

I stand by my engine mount statement, both David and Dennis are at the mileage where you'd want to consider replacing. The engine not being properly centered will exacerbate exhaust rattles.

[dennis]

OK. It seems unanimous- engine mount, leading to exhaust noise. Just a few questions: will this cause damage to drivetrain and how difficult is it to replace the mount? Should I replace all? Assuming I should.

[dennis]

Can anyone recommend the best mount to buy? I have seen Wevo and Pedro's mount, but what is best as far as long lasting durability?

[yimmy149]

It's usually only the front mount that needs to be replaced. It's not super difficult, just time consuming. You have to support the weight of the engine while you are doing it, so you need a jack that doesn't leak down, or an engine support bar. If you go the support bar route, it's helpful to have a second person to help install it, and adjust it while you are under the car. I tried to do it myself and dented my fender.

I have Pedro's Enthusiast mount. I think a lot of it depends on whether you want the car to be a smoother quieter daily driver, or more aggressive. You can feel engine vibration through the seat with Pedro's mount around 3,000 rpm. The stock Porsche mount is quieter, but probably won't last as long.

-james

[dennis]

Thnaks for the help here...I really appreciate it. I'll post back when I have it all fixed.

[Bladecutter]

Originally Posted by dennis

OK. It seems unanimous- engine mount, leading to exhaust noise. Just a few questions: will this cause damage to drivetrain and how difficult is it to replace the mount? Should I replace all? Assuming I should.

I don't think its unanimous.

You should check one more thing, however, before you start spending money.

The muffler has a bracket that mounts to the rear of the transmission.
On my car, the three bolts that support the bracket and muffler are all broken.
When the engine is at the right rpms, these bolts start to rattle, and make one heck of a racket. This rpm point is usually a fast idle speed, so right around 1k rpms.

Take a look.

BC.

[dennis]

do you hear the rattle in gear only? Mine is only in gear, which makes me think its due to the engine torquing

[Matt Fredrikson]

Mines also rattles in gear on the gas only, 2800 rpm in gears 12&3 everytime o the number?? Gonna beat on the heat shield this weekend.