Ever since a mitsu dealer replaced the alternator, the heat shield buzzes when the rev is between 2500 and 2700 RPM. Anyone know a quick way to stop it? Is it safe to remove the heat shield. Bear in mind I have an HM header fitted.

Cheers,
Vlad

heat shield on your headers? yeah its fine to remove it. I'd probably say it needs tightening.

;1209677']heat shield on your headers? yeah its fine to remove it. I'd probably say it needs tightening.

The original heatshield was refitted after fitting the header.

With removal, what is the best way to do it?

Or you could take it back to the dealer and get them to fix it for free?

should just be 3 x 10mm bolts holding it on....should not be hard to remove

Or you could take it back to the dealer and get them to fix it for free?
Done that. They said the guys fitting the alternator must have rested it on the heat shield and may have slightly dented/warped it. They fitted extra washers to lift the heat shield a little but it still buzzes. Will try to remove the heat shield tomrrow to see if it helps.

Done that. They said the guys fitting the alternator must have rested it on the heat shield and may have slightly dented/warped it. They fitted extra washers to lift the heat shield a little but it still buzzes. Will try to remove the heat shield tomrrow to see if it helps.

Then tell them to give you a new one?

Dealers need to be accountable for their ****ups.

I've got hm's and there's no heat sheild on mine

Cheers guys. Will definitely remove it this weekend. Its really annoyning. VROOOOM BUZZZZ VROOOOM.

Yeah HM's you can put them back on.

I have got mine back on and all going well.

Can you source where abouts exactly the buzz is comming from? There is nothing to them so i'm not sure how they could buzz unless not done up tight.

Find where the buzz is and if it is rubbing on something then bend it away so it doesnt buzz.

I think its more the right rev gets the shield buzzing at its natural resonance, and causes the noise. one of mine does the same thing and all are tight, bloody annoying. Like you said i did notice that mine started up when one of the shields got slightly dented, although it wasnt touching anything.

Well, removed it this arvo, 3 12mm bolts. Went for a drive and the buzzing was noticably reduced. There is still a muted buzzing at the same rev, possibly the rear heat shield. Is that one easy to remove?

Why are you blaming the heat shields? They are only amplifying the vibration of the thing they are attached to, ie the headers.

Manufacturers like Mitsu put a lot of time and effort into reducing NVH (noise, vibration and and harshness). If you replace a solid lump of exhaust manifold with much lighter tube headers, you will get a harmonic buzz at some frequency, but I doubt if the manufacturer - any brand - of the headers has tested them on a vehicle and tried to tune out harmonics.
Removing the heat shields, which would be acting as sound amplifiers (by moving the air back and forth when the header vibrates) should reduce the noise, and even shift the rev point a bit, but you may have to live with it.

Have a look under the car while someone runs the engine through the resonance point - I bet the headers will be moving about in a blur! lol

Before you remove heat shields be aware that headers get red hot and rubber/plastic bits don't like radiant heat!

Why are you blaming the heat shields? They are only amplifying the vibration of the thing they are attached to, ie the headers.

Manufacturers like Mitsu put a lot of time and effort into reducing NVH (noise, vibration and and harshness). If you replace a solid lump of exhaust manifold with much lighter tube headers, you will get a harmonic buzz at some frequency, but I doubt if the manufacturer - any brand - of the headers has tested them on a vehicle and tried to tune out harmonics.
Removing the heat shields, which would be acting as sound amplifiers (by moving the air back and forth when the header vibrates) should reduce the noise, and even shift the rev point a bit, but you may have to live with it.

Have a look under the car while someone runs the engine through the resonance point - I bet the headers will be moving about in a blur! lol

Before you remove heat shields be aware that headers get red hot and rubber/plastic bits don't like radiant heat!

I've got HM Headers which were designed for Mitsus. I doubt the ralliart magna buzzes. Anyone know if there is a material that can be stuck on to the outside face of the heatshield which will reduce the buzzing. Will the matting that is stuck to the underside of a bonnet work?

Also, is it placebo affect or something else that I noticed the car has more pickup without the heat shield. It is something to do with heat trapped under the heatshield?

*groan* Don't use the underbonnet material on a heatshield as it catches fire easily!

(Seen a Mitsu on fire because the bonnet material drooped onto the exhaust on a 2.6)

I noticed a buzzing that seems to be coming from the cat converter area. Only does it at 2000 rpm. Is there a heat shield in that area that can be either re-enforced or totally removed?

Stock cats are wrapped in a thin metal shield.

ive got the same problem atm which is drivig me crazy, i looked at my heat shields and hoped that is the problem, but isnt that easy, after jacking the car up and having a closer inspection, i found that it must be the (engine pipe/y joiner) im still in the process of getting it fixed but will keep you posted...

read this thread, its exactly what my problem is...maybe its yours also....
http://www.aussiemagna.com/forums/showthread.php?t=73164&highlight=exhaust+rattle

Stock cats are wrapped in a thin metal shield.

Yep, confirmed today it was the heat shield on the cat....it was vibrating on idle in the morning, so I reached under and touched the heat shield and the vibration stops.

Now all I need to do is figure on a permanent solution. Any ideas anyone?

A couple of turns of fencing wire should hold it down.

Why are you blaming the heat shields? They are only amplifying the vibration of the thing they are attached to, ie the headers.

Manufacturers like Mitsu put a lot of time and effort into reducing NVH (noise, vibration and and harshness). If you replace a solid lump of exhaust manifold with much lighter tube headers, you will get a harmonic buzz at some frequency, but I doubt if the manufacturer - any brand - of the headers has tested them on a vehicle and tried to tune out harmonics.
Removing the heat shields, which would be acting as sound amplifiers (by moving the air back and forth when the header vibrates) should reduce the noise, and even shift the rev point a bit, but you may have to live with it.

Have a look under the car while someone runs the engine through the resonance point - I bet the headers will be moving about in a blur! lol

Before you remove heat shields be aware that headers get red hot and rubber/plastic bits don't like radiant heat!

I remember that the HM Headers came with HPC coating. Does anyone know how much heat it traps? How does having HPC without heat shield compare with no HPC but with heat shield?

Vlad.....and others......i'd be interested to know your thought's on the above also.....as with the RPW's....all the shield are off......and i have the Ceramic coated ones too. as mentioned before though.....there's still considerable Radiant heat...and soak.

Cheers,

Wayne.