jvakos

anyone experience a whistle sound like this from the engine left side?


its a whistle type noise coming from the left side which i hear at idle and the noise increases if i tap the accelerator pedal (see video).

BUT when driving it goes away if i am accelerating and am on the accelerator pedal but it then comes back when i am coasting/not touching the accelerator pedal.

i slipped off my belt to check if it was a bad bearing on the water pump or alternator and also checked all the other pullies and they all spin fine zero noise so assuming its not a bad bearing.

could it be a leak of some sort??? i dont have any performance issues or any CEL's just this noise happening for about 2 weeks and has progressively gotten louder so getting me worried..... car is going to the shop next week maybe time for a compression test or something.

thx john

Morphh

It sounds to me like a vaccum leak,check PCV hoses there are 2 one on each side of the valve covers going to bottom of throttle body. To me sounds like vaccum leak

jvakos

Morphh - think youre right on the vacuum leak...the hoses are all connected to the breather box as far as i can see.

i attempted to gently tighten the bolts on the breather box thinking perhaps it was slightly loose and found that the rear smaller torx bolt was not only super loose but is snapped (see pic) and just stuck in the slot held in with with black sealer.

I checked the other smaller front torx bolt on the breather box and unscrewed it to do a sanity check on the length and that one is about 1 inch long so clearly the other one was broken which you can see from the pic attached.

i pressed in a small strip of aluminum HVAC tape on the bolt and slot to hold the broken bolt in while i drive it to the shop and the whistling sound is much less, but still noticeable so am guessing thats the culprit.

thx Morphh once again you have been tremendous help!

jvakos

the shop confirmed my whistle noise is a vacuum leak coming from the where the intake manifold pipe connects with a rubber hose/clamps to the lower Y-Pipe.

they said those rubber hoses that connect that manifold pipe to the y-pipe are pretty degraded (see pics) so not sealing properly... the sound went away for about 2 days after they tightened the clamp on the hose but is back.

can these be re-sealed or do you just buy new rubber hoses???

If new, what is the part number for those hoses??? I cant seem to find so maybe it only comes with a new intake manifold or new lower y-pipe which i cannot deterime from those parts so may call dealer...

http://www.mboemparts.com/oe-mercedes-benz/1120900031

http://www.mboemparts.com/oe-mercedes-benz/1120980207

Morphh

I still think it's where the 2 PCV connect to underneath the throttle body, it could be those rubber clamps as well let me know, check out needswing for parts

jvakos

Morphh - i will take a look at that thanks. what do those 2 PCV hoses (or whatever they are) look like that connect underneath the throttle body? am trying to find them but cant tell from pics of that area (attached from different site) what those look like to check out.

i removed my intake y-pipe and could see a little more back there, but might need to remove the throttle body to get a good look at what you're referring to with those PCV hoses/connect as this noise is driving me nuts

Morphh

U might have to take off one of
the intakes, both PCV pipes come together T and our plug
In under the throttle body. U can't see with that pic u have look up catch can from needswing I think there is diagram there on how it connects

jvakos

Think i found the correct hose part number.... this is for the one that connects the intake manifold to the lower Y pipe in the back of the supercharger is #1120942282. May just buy 2 of these get my cracked/deteriorated ones replaced and see if that stops this whistle noise......

in case anyone else has this issue, here's a good diagram of the parts for that entire area....

http://www.mbpartsworld.com/p/__/HOS...120942282.html

http://www.mbpartsworld.com/showAsse...sembly=1076716

Morphh

Have u checked the PCV pipes where they connect to the throttle body?

Morphh

Have u checked the PCV pipes where they connect to the throttle body? U can check by spraying water with dish soap to see if u see bubbles in any rubber pipes u see, it might help

Morphh

I ask u question abt belt tensioner? U notice a noise cmg from brand new one, I put new one on and it's making a rattling noise when in gear.

jvakos

Morphhh - heres a video of my new belt tensioner which i installed an didnt havey any issues with regarding noise or vibration.


ttps://www.youtube.com/watch?v=dgI7YLR_YGI

With that said, the old tensioner here which is the original 13 year old definitely had some wobble/movement but seems some level of movement is normal compared to the new one so not sure exactly what benefit the new tensioner provided but for 150 bucks and couple hours of my time was worth replacing

Morphh

What serpentine belt brand u running

Kobalthopsing

Cold you tell me, What was the reason off the whistle Noise. I. Have the Same Problem.
Best regards
Andy

Kobalthopsing

Could you say the reason of the whistle sound?

Morphh

most likely a vacum leak from pcv hose
they tend to disintegrate from inside out from the oil being sucked through them

Viper98912

I think you guys are wrong, because it's the woo woo making the whistle sound you hear.

jvakos

was the two hoses that connect the intake manifold to the lower y pipe thats behind the supercharger - see my other post here with the part #1120942282. my hoses were both dry/cracked and after replacing the whistle sound was gone. good luck

its the hose labeled #690 on the diagram here from mbpartsworld

http://www.mbpartsworld.com/p/Merced...120942282.html

http://www.mbpartsworld.com/p/__/HOS...120942282.html

http://www.mbpartsworld.com/showAsse...sembly=1076716