Exhaust Squeal
 

As of late, I've been dealing with an exhaust squeal on the Dangermobile that's starting to drive me f'in nuts ! Basically, the squealing occurs during start-up/idle, and remains prominent until the vehicle warms up. During warm-up, the squealing is most noticeable during short blips of the throttle and/or with falling RPM's. The squealing never fully goes away even when things are up to temperature. But, it is somewhat mitigated when the vehicle is fully warmed up. Strangely, I can isolate and stop the squealing by simply putting pressure on the exhaust tips or pushing against the right side cat delete pipe. Leading up to this, I've tightened every nut, bolt and clamp, to include the muffler strapping to no avail. Today, I went so far as to try and cold set the position of the muffler by inserting a sturdy wooden dowel into one of the exhaust tips and moving the muffler slightly up ward. And, for a brief period it seemed as though the problem had been solved. However, after a few miles of driving the dreaded squeal was back. Any thoughts ?

p.s. The possibility of a defective cat, resonator, delete pipe or clamp as being the culprit, has pretty much been ruled out at this point. It's like an f'in ghost in the machine ?

Did you check the seal on the lambdas ?

The pre-cats are fine. I have no secondaries to check.

The thread on the o2 sensors ....

Yes, I know what you're referring to. The 02 sensors on the pre-cats are fine, and I have no secondary cats, and therefore no 02 to sensors to check on them. Thanks for the thought though.

It's probably a werewolf in the muffler then ....

I was thinking maybe a Wolverine ?

JD
Just a swing in the dark. I have read of these symptoms being a loose spark plug squealing on cold startup. Anyone been in that area lately?

Since I can isolate and stop the squeal by putting pressure on the exhaust, I don't think it would have anything to do with the spark plugs.

Johnny, if you can stop it by putting pressure on the tailpipe then simply take the car to a welder, add that same pressure you are talking about, and get him to do small welds around the connecting pipes at the same time you are pressing on it. That should be enough to retain the tension.

A temp fix yes but maybe you'll be lucky and it will last eternally!

For what it is worth - I had a squeal on my fabspeed on my last boxster. I found out after obsessing about it for a month that one of the mufflers had settlesd a bit and it was rubbing the heat shield material in the bumper. It was so hard to find in fact that the only way I could do it was to put my self in danger - no pun - and basically had to have the wife rock the car back and forth clutch in and out while revving) as I laid very close to the back end. finally saw the rubbing happening. Took it back to the shop and they cut some material away and it was gone. The shop even thought I was nuts at first until we saw the scratch marks on the muffler. Passenger side was hanging just slightly lower than driver side muffler.

Thanks for the advice, but I already checked for rubbing against the heat shield - nothing.

I have a cunning plan ....

Get it squealing , then hold a rag over all the joints one at a time listening for a difference .
a welding gauntlet could be used if you have one ..

sounds like a drone...

Drone ? What would make you think that ?

Cold be the Chinese bugging device, are there any new "diaper service" vans in your neighborhood parked for extended periods?

I think what he meant is he can hear it, the drone sound, you know

- cut/weld a small 1" V shaped fin under the tailpipe
- Pressure on that tailpipe, to your sweet spot
- tak the fin to the muffler
- you are done (for two months anyway lol)

If you can't find the bug then its happening inside the can. You'll have to slice it open. You'r screwed in other words. A quick and dirty weld might save your arse if lucky

Does the squeal sound like a kid letting air out of a balloon while pinching the orfice?

Youve got a loose orfice then. No need to fret just excuse yourself, turn up the music and lay off the prunes for a while. :p

I've become a victim of my own sarcasm and loquacity :(

I going to have my associate Whitey Bolger get in touch with you, he knows how to handle squealers. He owes me a favor so don't worry about payment! :cool:

I prefer "Rifleman Flemi" if it's ok.

Oh...sweet irony...

are your holidays nearly finished madmods?;)

JD solution-but plug!:cool:

Ye reap what ye sow big guy!:ah:
AKL

Many have pm'd me suggesting that it may in fact be a loose plug after all. Sound plausible ?

seat.....edge.......resolution I cannot wait!

I checked for a loose spark plug(s), along with a possible loose the 02 sensor, today. Everything was ok - the squeal continues. :(

Get yourself a roll of this and have a party under the Dangermobile.

Aluminum Foil Tape :3M US

JD...
Does the noise disappear when the underside is wet (I know you don't take your car out in the rain...) but if you spray water - or better still kerosene - onto the engine mount / suspension / exhaust and see if the squealing reduces or - even - disappeares.
I suspect a dry engine mount or exhaust joint.......

The squeal persists, even when driving in wet conditions. As far as a dry engine mount is concerned, anything is possible, but it seems very unlikely due to the symptoms.

Did you mention whether it was proportional to engine speed?

Could it be that the header or header gasket is not torqued down properly and leaking a bit.

From too many years of experience, always consider the most unlikely to be perfectly possible, especially when you've run out of logical ideas.


In light of that you might also want to check for a covertly planted critter whistler or a racing pig taking up residence near by.:eek:

The squeal persists at idle (especially warm up), and is more pronounced with "blips" of the throttle and falling RPM's. As I mentioned, the squeal can be isolated by putting pressure on the exhaust in various locations. So far, the hanger, clamps and strapping have all been checked for looseness, and tightened if needed.

google "whistling cat converter"; whistling can be a symptom of a clogged cat.

except I reread your initial post - you ruled out your cats?