Squeak after engine/ignition shut off

[M6-Coupe]

Originally Posted by Fantasm

I bet if you got a Toyota it wouldn't make any more noises.

[M5 RAG]

Originally Posted by ghueser

I might spray a little WD-40 on the hinge points of those valves once the exhaust cools down. Might not last long but will see what it does.

That is one thing I have definately noticed with this car.....OMG that exhaust gets hot! You can feel the waves of heat getting out of the car.

Don't waste your time with WD-40, that will last about 30 seconds, either wire the valves open (highly recommended) or try and get some high temp grease into the bushings

[ghueser]

Originally Posted by M5 RAG

Don't waste your time with WD-40, that will last about 30 seconds, either wire the valves open (highly recommended) or try and get some high temp grease into the bushings

Yeah I agree. WD will just last a few seconds. Have been searching some other high temp alternates today.

[v3n0m]

I have the same thing. Dealer is looking at it tomorrow. Thought is that it might be the secondary parking brake.

Here's a video of the sound I made:

[M5essex]

IT'S THE EXHAUST VALVE...... Stand at the back and get someone else to drive, stop and turn off ignition.

[v3n0m]

Yup, verified it's the exhaust flap.

[ghueser]

I also have the squeak and based on comments from this thread agree it is the exhaust valves. After some searching I finally found a graphite spray lubricant that may have fixed the issue. The lubricant is called "dgf 123" and is basically ultra fine graphite suspended in a liquid so it can be sprayed onto surfaces. The liquid dries in about 3 minutes, leaving behind the graphite, which is good for up to 3000°F. I sprayed the top and bottom hinge points of the valves 3 nights ago (the exhaust was cool) and so far results are good. I cannot hear any noise at all. Limited test so far, but even if it only lasts a couple of months before needing a re-spray, thats ok with me.

[v3n0m]

Did you spray the inner or outer part of the exhaust (or both)?

[ghueser]

Originally Posted by v3n0m

Did you spray the inner or outer part of the exhaust (or both)?

For now, I just sprayed the top and the bottom outer hinge joints. I could have sprayed the inner ones as well but wanted to see how well the outer ones would do. The only issue I ran into was the fact that the can's spray tip is like a regular spray can. Easy enough to use on the bottom hinge, but cannot get close to the top hinge. What I ended up doing was swapping the tip with one I had with a long plastic spray tip. (Carb cleaner can) With the long tip, I was able to get to the upper hinge.

[v3n0m]

I solved the issue. As mentioned by many people this is the exhaust flap of the stock exhaust. All I did was apply high temp ceramic lubricant liberally around the outside hinges of the flap mechanism and using a stick on the inside hinge of the flap (have to reach into the exhaust opening, so do it when it's cold). Less than $2 fix.

http://www.amazon.com/gp/aw/d/B004AB...528360_TE_dp_5