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Car has now been with the dealer for 6 days, So the process seems to be.. Misfire, change plugs and coil pack. Then if it doesn’t go away consult mercedes technical and request authority under warranty to do more tests, such as the compression test. Then borescope the offending cylinder to see if the is anything obvious, then if not break down the engine... this is the point I am at now. On the plus side the a250e is not a bad courtesy car and has saved me a fair bit on fuel...
 

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Would be good if a motoring journalist picked up on this like they did with the focus RS head gasket issues... this seems to be a fairly serious issue that is getting more rife by the day...
 

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I've got to the point where im now thinking "when is this going to happen to mine?" Rather than "Is this going to happen to mine?"
Knew I should of gone for the 45 :ROFLMAO:
 

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I've got to the point where im now thinking "when is this going to happen to mine?" Rather than "Is this going to happen to mine?"
Knew I should of gone for the 45 :ROFLMAO:
I wouldn't get too downbeat about it. Most of us, including me, had to have our turbos replaced on the original A45. But after the fix nothing else went wrong.
 

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Just been updated by the dealership. The head has been totally disassembled. Valve guide failure. So new head and valves are on the way from Germany. It arrives like a lego set and needs built so it will take another week. But on the plus side.. good communication from the dealer. They seem genuinely annoyed that it happened.. Car was only worked on by the AMG trained master tech and parts are available and being shipped urgently. All under warranty... and the a250e is an interesting courtesy car. Problem shouldn’t have happened but it’s the dealing with it that counts for me.
 

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Hi all,
I'm new to the Mercedes A Class community but have a little story for you all.
I recently purchased a 6 month old AMG A35 from a main dealer. Had a few months and have loved it up until last weekend when engine light came on. Called Merc who sent out technician. Diagnosed coil pack and fitted new. Next day having driven a few miles without issue engine light came back on and same 3 cylinder rough running engine was back. Car went in to main dealer who advised a valve problem (no further info on this yet) New head now being fitted. Anyone else had this issue?
Yes! Just found out my 2020 a35 needs
new head, 10 months old, 20,000 miles, very disappointed, will be weeks in the shop I’m told.
 

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Good point. Let me add symptoms to the poll.
 

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I drive with the oil temp gauges on screen I noticed the oil running a bit hot. It was getting towards 111oC on a few occasions but no consumption issues. I think fuel economy had taken a bit of a hit too, but I may just have retrospect positive bias.. All was grand until the misfire.
the dealership did admit it was a common fault that MB technical are seeming now, that was something I wanted recognition of at the outset.
 

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Apart from the misfire - were there any other symptoms? Eg Oil usage?
Funny you should mention that...
Since you can’t manually check the oil, you have to go by the sensor in the dash, mine toggled from full to half quart low, different times different days,
I was told by dealer that’s normal 🤔
 

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A question for those of you unfortunate enough to have experienced this fault... Could you describe the misfire symptom in more detail please? Also, is there always a warning light that accompanies the misfire?

Sorry for your woes but would really appreciate more information on this issue. Thank you.
 

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Is an oil temperature above 100c common in the A35. I've never seen it that high in my A45s and only saw it just above 100c very briefly a couple of times in my previous A45. I would have thought 111c, especially more than once, would be a red flag.
 

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Is an oil temperature above 100c common in the A35. I've never seen it that high in my A45s and only saw it just above 100c very briefly a couple of times in my previous A45. I would have thought 111c, especially more than once, would be a red flag.
From memory, I think my car is usually around 102-106c when fully warmed up
 

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A question for those of you unfortunate enough to have experienced this fault... Could you describe the misfire symptom in more detail please? Also, is there always a warning light that accompanies the misfire?

Sorry for your woes but would really appreciate more information on this issue. Thank you.
the first symptom I was aware of was a a check engine light followed by what felt like an engine that was off a cylinder. The the error codes for this one came up as fuel pressure not plausible. These were reset and the car was ~ok for the next day or two.. then the 2nd time it happened, same off a cylinder issue and CEL but when it got to the dealer it had the misfire codes as well.
 

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I seem to get around 100-105 cruising on the motorway 88-99 round town for the oil temp.
 

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I suppose now that I know the valve guides had been compromised I can see why the oil temp went up. There was likely enough blow by through the ruined guide channel to affect oil temp. Oil is likely to be ruined now too but I would expect that if you replace a head you would need fresh oil since all fluids are likely to have been drained during the strip down.
 

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Another one (misfire) being reported on facebook this evening. Just over a month old, run-in as per instructions.
 

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Is it possible to direct them to this forum and perhaps they can fill in the poll which might get MB to take remedial action sooner rather than later.
 
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