Goose honking noise at start up?
Thread Starter
Junior Member
Joined: Apr 2023
Posts: 50
Likes: 19
From: Cedar Mill, OR
C450 AMG
Goose honking noise at start up?
Got one for the experienced esteemed forum members: After my recent fun with an impromptu replacement of an AOS & crankcase breather pipe assembly, my gal has taken to making 3 quick goose honks on cold start cranks coupled with a surge/stutter of rpms - about about 2 seconds of initial crank. The "honks" are low & bass tones in quick succession; each quieter than the first. It occurs before the pressure build up in the VVTI. The cold start idle up is normal on RPMs, except for the honks (burps? blats?) that happen like mini strokes and then the motor settles slowly into regular idle with no other weirdness. Everything else is normal post start up too. I did find two screws loose on the metal o-ring clamps that affix the plastic intake to throttle body, but the goose honks did not go away after tightening those suckers down.
Warm or hot starts do not create any honks or hiccups. I can start the car after 8 hours of sitting and it doesn't make honks. Walk out to the car the next morning (after sitting 13 hours): it friggin honks on cold start.
Any ideas? I'll be having the resident shade tree mechanic throwing my car up on his lift for an in-depth inspection later this week. Barring that outcome, next stop will be the local MB Indy shop.
I'll try to see about recording it for those who love M276 mystery noises.
5,000 mile oil (& filter) change intervals observed with M1 Euro Syn 5W-40 SQ rated. No (noticeable) oil loss between changes and no drop in fuel economy apparent. No codes stored. Now at 164,440 miles.
Warm or hot starts do not create any honks or hiccups. I can start the car after 8 hours of sitting and it doesn't make honks. Walk out to the car the next morning (after sitting 13 hours): it friggin honks on cold start.
Any ideas? I'll be having the resident shade tree mechanic throwing my car up on his lift for an in-depth inspection later this week. Barring that outcome, next stop will be the local MB Indy shop.
I'll try to see about recording it for those who love M276 mystery noises.
5,000 mile oil (& filter) change intervals observed with M1 Euro Syn 5W-40 SQ rated. No (noticeable) oil loss between changes and no drop in fuel economy apparent. No codes stored. Now at 164,440 miles.
MBWorld God!
Joined: Dec 2019
Posts: 32,406
Likes: 6,337
Got one for the experienced esteemed forum members: After my recent fun with an impromptu replacement of an AOS & crankcase breather pipe assembly, my gal has taken to making 3 quick goose honks on cold start cranks coupled with a surge/stutter of rpms - about about 2 seconds of initial crank. The "honks" are low & bass tones in quick succession; each quieter than the first. It occurs before the pressure build up in the VVTI. The cold start idle up is normal on RPMs, except for the honks (burps? blats?) that happen like mini strokes and then the motor settles slowly into regular idle with no other weirdness. Everything else is normal post start up too. I did find two screws loose on the metal o-ring clamps that affix the plastic intake to throttle body, but the goose honks did not go away after tightening those suckers down.
Warm or hot starts do not create any honks or hiccups. I can start the car after 8 hours of sitting and it doesn't make honks. Walk out to the car the next morning (after sitting 13 hours): it friggin honks on cold start.
Any ideas? I'll be having the resident shade tree mechanic throwing my car up on his lift for an in-depth inspection later this week. Barring that outcome, next stop will be the local MB Indy shop.
I'll try to see about recording it for those who love M276 mystery noises.
5,000 mile oil (& filter) change intervals observed with M1 Euro Syn 5W-40 SQ rated. No (noticeable) oil loss between changes and no drop in fuel economy apparent. No codes stored. Now at 164,440 miles.
Warm or hot starts do not create any honks or hiccups. I can start the car after 8 hours of sitting and it doesn't make honks. Walk out to the car the next morning (after sitting 13 hours): it friggin honks on cold start.
Any ideas? I'll be having the resident shade tree mechanic throwing my car up on his lift for an in-depth inspection later this week. Barring that outcome, next stop will be the local MB Indy shop.
I'll try to see about recording it for those who love M276 mystery noises.
5,000 mile oil (& filter) change intervals observed with M1 Euro Syn 5W-40 SQ rated. No (noticeable) oil loss between changes and no drop in fuel economy apparent. No codes stored. Now at 164,440 miles.
Thread Starter
Junior Member
Joined: Apr 2023
Posts: 50
Likes: 19
From: Cedar Mill, OR
C450 AMG
Thanks W205C43PFL! It is naturally not called a "pressure transducer" via FCP Euro, but instead a "boost control valve". Two different options available listed for a C450 model:
"Pierburg" 0101531328 Mercedes Control Valve @ $83.99
or
Mercedes branded 0001531800 "turbocharger boost sensor" @ $141.99.
They both look identical in picture illustrations & descriptions. The Pierburg version is highlighted as the OE (?). I pulled the trigger on the cheaper Pierburg part. I'll report back on how it goes~
"Pierburg" 0101531328 Mercedes Control Valve @ $83.99
or
Mercedes branded 0001531800 "turbocharger boost sensor" @ $141.99.
They both look identical in picture illustrations & descriptions. The Pierburg version is highlighted as the OE (?). I pulled the trigger on the cheaper Pierburg part. I'll report back on how it goes~
MBWorld God!
Joined: Dec 2019
Posts: 32,406
Likes: 6,337
Thanks W205C43PFL! It is naturally not called a "pressure transducer" via FCP Euro, but instead a "boost control valve". Two different options available listed for a C450 model:
"Pierburg" 0101531328 Mercedes Control Valve @ $83.99
or
Mercedes branded 0001531800 "turbocharger boost sensor" @ $141.99.
They both look identical in picture illustrations & descriptions. The Pierburg version is highlighted as the OE (?). I pulled the trigger on the cheaper Pierburg part. I'll report back on how it goes~
"Pierburg" 0101531328 Mercedes Control Valve @ $83.99
or
Mercedes branded 0001531800 "turbocharger boost sensor" @ $141.99.
They both look identical in picture illustrations & descriptions. The Pierburg version is highlighted as the OE (?). I pulled the trigger on the cheaper Pierburg part. I'll report back on how it goes~
https://cimg2.ibsrv.net/gimg/www.mbw...1d5e506909.jpg
Thread Starter
Junior Member
Joined: Apr 2023
Posts: 50
Likes: 19
From: Cedar Mill, OR
C450 AMG
Okay. Cold start goose honks are back...BUT they seem to be diminished/quiet compared to what they were previously. They are soft enough in nature that my wife doesn't hear/notice them - but I know the quacks are back. Since they are less pronounced, I'm assuming that they must be related in nature or part of the same (eco)system as the "transducer"/boost control valve I just replaced...such is the logic of my non-mechanical minded smooth & soft brain.
Other than short muffled honks on start up, all other functions & operations are normal. Open to receiving more forum direction/advice.
(Sigh)
I am starting to really dislike the plastic fantastic automotive world~
Other than short muffled honks on start up, all other functions & operations are normal. Open to receiving more forum direction/advice.
(Sigh)
I am starting to really dislike the plastic fantastic automotive world~
Last edited by SizzlCheez7; May 8, 2026 at 07:43 PM.
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MBWorld God!
Joined: Dec 2019
Posts: 32,406
Likes: 6,337
Okay. Cold start goose honks are back...BUT they seem to be diminished/quiet compared to what they were previously. They are soft enough in nature that my wife doesn't hear/notice them - but I know the quacks are back. Since they are less pronounced, I'm assuming that they must be related in nature or part of the same (eco)system as the "transducer"/boost control valve I just replaced...such is the logic of my non-mechanical minded smooth & soft brain.
Other than short muffled honks on start up, all other functions & operations are normal. Open to receiving more forum direction/advice.
(Sigh)
I am starting to really dislike the plastic fantastic automotive world~
Other than short muffled honks on start up, all other functions & operations are normal. Open to receiving more forum direction/advice.
(Sigh)
I am starting to really dislike the plastic fantastic automotive world~
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Thread Starter
Junior Member
Joined: Apr 2023
Posts: 50
Likes: 19
From: Cedar Mill, OR
C450 AMG
Inspected, cleaned, and re-installed both coolant reservoir caps (turbo & motor) last night. No goose honks or stutter on start up this morning. Hurrah for zero dollar fixes! Thanks yet again W205C43PFL~
MBWorld God!
Joined: Dec 2019
Posts: 32,406
Likes: 6,337
