I have had a lot of issues with my A35 (that I love) as it was one of the first batch of vehicles delivered to customers (Registered 1st March 2019) from brake issues, parts of exterior & interior trim missing, suspension warning messages, centre console buttons stuck/fitted wrong, constant passenger airbag failure warnings, dashboard rattles/Pillar rattles and software failures that have caused my dash to go black while driving at motorway speeds and forced me to emergency stop and shutdown the vehicle and wait 10 mins before unlocking again at which stage it is fixed.

However I have not had any engine warning issues and I haven't heard of anyone else getting them, I would personally suggest if you can at all that you should exchange it for a different used A35 or return it for a full refund as it does not sound like its going to be reliable vehicle at all! How many miles did it have on it when you purchased it and which dealer did you get it from as a vehicle only 6 months old with engine warning lights and requiring a new headers sounds like it was an MB World track car which has been driven like it was stolen from day one and never run or looked after.

If you cannot return it or exchange I would suggest you speak to your dealer and request they give you a signed letter fully confirming the warranty length on the vehicle and also confirming what it was used for prior to sale as if it was an ex demo MB World track vehicle and they didn't inform you of this prior to purchase you would have very strong grounds to take the dealer to court for a refund.

 

I've only heard of 2 UK cases of A35 engines needing to be replaced under warranty, they are both documented in the A35 facebook group.

Your case sounds like the variable valve mechanism has stopped working in the cylinder head.

 

Hi,just had the same issue with my A35...had the car for a year and i started the car on Monday and it was idling oddly,I went to the petrol garage and when I went to restart it was idling poorly again and lost power....Mercedes Breakdown diagnosed a mis fire on cylinder 3...its been at the mercedes garage since and I rang them today to get an update and they have said that there is a cylinder failure and that they have never seen this on this car type before and are in contact with mercedes technical with how to resolve and have mentioned a head replacement....think I'm going to ring them tomorrow as there's more in this then there letting me know.

 

Hi All,just an update...my car had to have the cylinder head replaced under warranty...poor communication from the dealer throughout tho,I got the car back after 2 weeks and then the coolant light kept coming on and then the engine light warning came up on the dash....it went back in and they diagnosed a problem with the inter-cooler so replaced that under warranty too,had the car back this week so see what happens next,hopefully that's the end of my problems.

 

Very few seem to have reported these engine issues on this forum or FB so I hope it is now resolved for you but also that other A-Class models in general aren't likely to suffer.

 

Thanks for the update.

 

There’s a whole load more reports on the A35 Facebook group in the last few months I’m afraid.

 

The reports are only for the A35 or for the A250 also?

 

Like London buses.

 

Its a fb A35 forum, so mainly A35’s on that forum being reported!

I think it’s a problem with the variable cam timing , it first manifests itself as a misfire ....

 

I was told told by the dealership that its more apparent in the A250 which we know is the same engine as the A35 but probably not well known about if people aren't on forums etc...I expect it just goes in and gets fixed under warranty either way,not sure if the inter cooler problem so close after the cylinder head change is part of it?

 

Also with the A250. My car is now in the garage for 5 weeks🤦🏻‍♂️.

 

A few more owners piling in on the A35 forum on facebook, reporting needing new cylinder heads, after a "misfire" symptom....

 

Mine is in at the minute with the same thing, C1 misfire. compression issue. Exactly the same symptoms.

 

Hi All,just for reference my cylinder head replacement was at approx just under 14,000 miles,unsure if there's been a minimum or a maximum mileage this has happened too through people's shares.

 

Most of the issues im hearing are with the 2019's but obviously this is due to them having covered more miles, just hoping that the newer ones don't have this problem, Mines Sept2020 70 plate so hoping I've missed it, Ive heard of a few 20 plates having the issue, but no 70's yet, which again could be due to the milage.

 

I’m hoping this too.. at least the replacement heads will be better in theory if this is the case. Really didn’t expect my brake pads to outlast my head....

 

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...

 

Hi
I'm having similar issue with my a180 but it's a 13 plate so no warranty for me. Do you know how they fixed this in the end?

 

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...

 

Not good times

 

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

 

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.

 

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.

 

Hi, I have virtually the same problem with my car, trying to get Merc to pay toward the £4100 repair as it is just out of warranty. Merc are claiming it is not a known issue, so I am trying g to gather evidence from other owners - would really appreciate any info you could give me.

 

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.

 

3 weeks for mine...

 

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 🤔

 

Good point. Let me add symptoms to the poll.

 

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.

 

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.

Hi, I am experiencing the same issues with my A250. Dealership is being difficult - which dealership were you dealing with that admitted it was a common fault (be grateful for any info as it may help me with my claim)

 

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.

 

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

 

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