nysid2007

Hi Guys, anyone who has some proper knowledge, give me some advice.

My engine has been producing this high pitched gas sound and Ive been

working on it to fix the cause.


Please check the above clip !
This video was recorded before below parts were replaced. And the car not does not produce this
noise for about 50 seconds after engine is turned on . After goes back to the vedio . damn it.

So far I've checked the entire vacuum lines and check valves and PCV at the

back of the engine. Front vacuum hose along with change over valve,

pneumatic line hose , Blue check valve has been replaced.

I came to an conclusion that this noise is not created by vacuum leak.

Since the noise starts after the engine is on. About 50 seconds later this

noise starts.

Any idea where to look for ??? I'm thinking some relay or some sort of electric

switch malfunctioning.

Critter

Does the noise change or stop when you apply some throttle, if no change then remove the serpentine belt and restart and check for noise. If no noise after belt removal start checking idler pulleys they have a tendency of seizing with age and will spin for a while when worn out, fresh pulleys only spin by hand for a short time.
Happy Diagnosing

nysid2007

Hey ~ thanks for the advice~!
Is idler pully visually inspectoable?? I mean I did take a peak since people
were telling me pully can creat noise like that , however couldnt find any
visual defects.

Also when I step on the gas noise does get louder but not noticeble. Only a
slight increase.

Critter

nysid2007,
Just for comfort slip the serpentine belt off using a 17mm socket and ratchet on the tensioner, then check all pulleys by spinning and rocking, the ones that spin for a long time will be on the way out. If they are allowed to completely wear out what usually happens is the bearing gets hot seizes and melts the plastic pulley off which in turn you loose AC, alternator, waterpump after shredding the belt and you are sitting on the side of the road. You have two options here, vacuum leak or bearing squeal. Check water pump alt and AC if the noise goes away

nysid2007

Hey Critter ,
Thank you for your help . I will go ahead and check the pulleys out !
Always wanted to install those wiesteck pulley kit . May be its time huh

When you say check the water pump , alternator how can I see them if they are working properly with out using STAR. I mean I can only see pump cover and alternator cover.

Critter

What I was speaking about is when the belt is off spin all pulleys by hand for source of squeal, alt and water pump the same turn by hand to listen for noise. any pulleys that wobble or make click noises, change. The Wiestec pulley kit is by far the best around and if you put that plastic OEM pulley crap back on your car then trouble will never be far behind. Both our cars run Wiestec thanks to Steve.
Trying to steer a 4000 lb beast with no power steering makes the wife angry if you know what I mean. For a few bucks a mechanics stethoscope is money well spent, harbour freight or any parts store should be able to help you out.

WHTEVO

Checking the pulley's would be my first guess as well. Good luck.

Critter

Just had a thought the AC compressor runs constant on a AMG, take a 8mm wrench and try to turn the compressor by hand, could be the clutch making that noise also or the compressor itself.
Again Good Luck

Jon2007E63P30

Pretty sure it is this
https://mbworld.org/forums/w211-amg/...-m156-e63.html

Does the whine continue for 2-3 seconds after the engine is turned off?

nysid2007

Hi Jon ~

I already replaced PCV valve, change over valve , entire front intake manifold
Vacuum hoses.
Only thing left is the intake manifold gasket. I'm pretty sure its the intake
gasket making the noise.
Yeah ~ the high pitched whistle continues for about 2 seconds and goes away.

Gotta find the parts number for the intake manifold gasket bolts. Any Idea?

nysid2007

Just checked entire , pulleys ~ None of them were making noise but , like
you said, one or two pulleys can use a fresh new parts. Going to replace those
along with serpentine belt as a preventive maintenance.
The noise is caused by wore out intake manifold gasket . Finally located the cause.

Jon2007E63P30

One good piece of info deserves another:
A004 990 53 12
$1.13 each below. You need 10. Startek mentions they are single use. Guess you knew that.
http://www.oediscountparts.com/parts...&siteid=215242

Gasket looks to be the same for left and right A156 141 04 80 (which is the replacement for A156 141 03 80)

nysid2007

Of course. Those bolts are aluminum and cannot be reused. Unless you just
lift the intake and slide out the gasket.

Jon thank you for the part number !!

Lets meet up some where in san francisco and grap a coffee !!

Thanks.

nysid2007

Jon !

Just got a question . When I order the intake gasket, do they come as a
pair ? Or do I need to purchase another one ?

Jon2007E63P30

The part number I gave was for a single off of startek. You might email the vendor I linked to. You are right, you would never sell just one.

When are you going to do the work on this? I might give you a hand if I am free. PM me

EDIT: Wonder if they still have them gaskets and bolts
https://mbworld.org/forums/engine-pe...ets-bolts.html

nysid2007

Problem Solved. Noise gone.
Bad intake manifold gasket plus carbon deposits interfering with valve actuation.
Carbon deposits removed, cleaned. Gaskets and intake bolts replaced.
Now I need new mounts soon, engine and tranny at the same time.

nardeezy@yahoo.

I think I have the exact same problem?

Did you have a CEL or decrease in performance?

What would something like this cost to fix?

nysid2007

I basically had a intake manifold valve not closing that is located inside the intake manifold. Due to carbon deposites stopping the valve from shutting
causing that whistle noise. I thought I had a bad purge/vacuum valve and replaced everything but it wasn't.

No I didnt have any CEL lights nor decrease in performance.

If you take it to the stealers, its going to be pricey. Not to mentioned parts intake itself is expensive.

nardeezy@yahoo.

To clarify, the noise was not caused by a bad intake manifold gasket, it was a bad valve in the intake manifold itself? What valve is this (part number/description), is it an emissions thing? Only valves that I though were in the intake manifold would be your actual intake valves?

nysid2007

well , gasket was not damaged but replaced since intake was off.
clogged up valve I believe.