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Discussion Starter #1
Afternoon,
Hope your all keeping well...
I’ve had my brand new a35 for the past month (cars done 750 miles now) and have noticed when starting to the car from stone cold that there is a slight tapping noise from the engine until the revs drop to normal idle speed and the noise then goes. Can other owners please clarify if this is just normal operation on cold start and the noise i am hearing is normal....hopefully I am worrying about nothing?
Thanks
 

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Afternoon,
Hope your all keeping well...
I’ve had my brand new a35 for the past month (cars done 750 miles now) and have noticed when starting to the car from stone cold that there is a slight tapping noise from the engine until the revs drop to normal idle speed and the noise then goes. Can other owners please clarify if this is just normal operation on cold start and the noise i am hearing is normal....hopefully I am worrying about nothing?
Thanks
I‘ve had this since new. There’s a thread somewhere in the forum with more info. You are most definitely not alone. Most opine it’s an injector noise that disappears after warming up. Other than this sound my car’s been mechanically without fault so I’ve long since given up thinking about it. I figure that if it was an issue it would have gotten worse/changed in some way since day one.
 
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Discussion Starter #4
I‘ve had this since new. There’s a thread somewhere in the forum with more info. You are most definitely not alone. Most opine it’s an injector noise that disappears after warming up. Other than this sound my car’s been mechanically without fault so I’ve long since given up thinking about it. I figure that if it was an issue it would have gotten worse/changed in some way since day one.
Thanks for your reply. Do the majority of owners suffer with it then?
 

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Thanks for your reply. Do the majority of owners suffer with it then?
I don’t think it’s in any way a majority, just not rare, and from the stuff I have read, not worth you losing sleep over. Also I think it may be specific to the A35/A250.
 

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I've found the noise is worse with 95 Ron Fuel, hardly noticeable with 99 ron (shel v power)
 

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I don’t think it’s in any way a majority, just not rare, and from the stuff I have read, not worth you losing sleep over. Also I think it may be specific to the A35/A250.
Not just the A35, my A220 on an 09 plate has the same noise. Same basic 2 litre engine.
 

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W177 A35 Sun Yellow Prem Plus w/ Aero Kit, Driving Assist, HUD, AMG Ride Control. Prev. W177 A200
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I bought my A35 from a supercar specialist dealer and almost walked away from it thinking the engine was dodgy due to this noise. However I found a video on YouTube of an A35 making the same noise.

The dealership reassured me that modern cars are increasingly like this. Due to emissions standards etc. the engine forces itself to warm up as quick as possible, resulting in this tapping noise. The owner showed me a video of an engine from a high performance Jaguar which sounded horrendous and he said he turned down the car from JLR, even though it was 6 months old and confirmed by JLR to be a perfect car mechanically. He also told me if I started any of his new lambos etc. I would find the same thing.
 

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I bought my A35 from a supercar specialist dealer and almost walked away from it thinking the engine was dodgy due to this noise. However I found a video on YouTube of an A35 making the same noise.

The dealership reassured me that modern cars are increasingly like this. Due to emissions standards etc. the engine forces itself to warm up as quick as possible, resulting in this tapping noise. The owner showed me a video of an engine from a high performance Jaguar which sounded horrendous and he said he turned down the car from JLR, even though it was 6 months old and confirmed by JLR to be a perfect car mechanically. He also told me if I started any of his new lambos etc. I would find the same thing.
Yep, Its a combination of a few things, Higher pressure fuel pump, and having OPF/GPF which the engine has to overcome now that its more restricted, so in turn it has to all work abit harder which makes it noisier. I've actually purchased one of these for my A35, they come on the CLA35 as standard, same exact engine and bonnet layout etc. No idea why merc gave them to the CLA35 and not the A35. under hood insulation, quitens it down a fair bit, couple this with 99 RON fuel and this issue is history.


7790
 

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Ahh, so Can / US 91 = RON 95.3

There are a few parts of the country which sell 93 = 97.4 RON but nowhere close to where I live.

Do UK / European manuals / fuel flaps recommend a min. octane? Our say 91.
 

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UK Recommended 98RON but will run (with ignition timing automatically retarded and less power) on 95RON.
 
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