It would be useful to get a handle on what's going on with the A35 engine and how many are effected and how long MB are taking to get the cars fixed
A35 Engine Cylinder Head Problem Poll
Forrester
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Looking at the poll 50% of people who answered have had this issue which seems to indicate a serious underlying floor in that engine. If there are no known occurances with the FL version do you know what updates were made to the engine or are they just newer and defects are not occuring yet. Im back into Mercedes this afternoon to arrange a courtesy vehicle but hey dont seem very knowledgeable about any engine improvements if there are any.
I don’t know yet of what MB changes were made to the FL version, if any. But I would hope MB would not put out the FL with a known design fault.
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I just got my A35 back from MB Oxford after a cylinder head replacement under warranty after only 28K miles. While the technician replaced the head, worringly he discovered a crack in the timing chain which was also replaced requiring full engine removal also under warranty. It's my first Mercedes and I have to admit my confidence in the vehicle is shot. Not only has it suffered a low mileage serious engine malfunction but there was also a potentially catastrophic mechanical fault in a component designed to last the life of the vehicle. I wont be keeping it unless I can keep a warranty on it which might be difficult. MB paid 75% of the warranty cost despite it being under warranty which to me indicates that the warranty company is pushing back on claims due to the design fault. I'm worried warranties might not be extended or if available will be prohibitively expensive.
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I understand your worries and agree.....
What I will say is "generally" MB warranty is better than most other manufactures...
How do I know?
Over 20 years of motor trade experience, dealing with many technicians, sales and aftersales staff who have worked at various brands.
It's VERY uncommon for an MB made engine to have a common major issue such as the one with the A35 engine types, the good thing about MB is that they cover sequential damage too (I wont go into full details of MB warranty and bore you haha).
Once MB vehicles are out of standard manufacture warranty they give you the option to extend, so this is an option for peace of mine.
I work for an MB dealership, so learn the trend of faults with many model and engine types, the fault you have experienced is really the only known common issue these cars develop, so yeah I agree it shouldn't happen, but it's been resolved,
So if you like the car, try and enjoy it, give it a second chance and see how you get on
What I will say is "generally" MB warranty is better than most other manufactures...
How do I know?
Over 20 years of motor trade experience, dealing with many technicians, sales and aftersales staff who have worked at various brands.
It's VERY uncommon for an MB made engine to have a common major issue such as the one with the A35 engine types, the good thing about MB is that they cover sequential damage too (I wont go into full details of MB warranty and bore you haha).
Once MB vehicles are out of standard manufacture warranty they give you the option to extend, so this is an option for peace of mine.
I work for an MB dealership, so learn the trend of faults with many model and engine types, the fault you have experienced is really the only known common issue these cars develop, so yeah I agree it shouldn't happen, but it's been resolved,
So if you like the car, try and enjoy it, give it a second chance and see how you get on
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Hi Jason that’s good information. I only bought the car in December so still have 20 months cover on the warranty and a service plan so I’m won’t do anything rash but I’ll definitely extend the warranty unless it’s hugely expensive. The car will still be under 50k by the so fingers crossed.
Look at around 28mins on this video. A good explanation about the engine valve problem.
Do you know if MB have done something with designed of the head to solve the problem highlighted in the video.
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I watched the video a few days ago and the mechanic suggested dropping the oil at 200 miles but when I asked Mercedes about it they didn’t think it was necessary. They said it didn’t even require bedding in but I’ve been driving it under 3K revs which I’ll do for the first 200. What’s your thoughts on this?
With the A45s and my previous A45. If I recall correctly, it was the first 1,000 miles at below 4,000 revs. I think 200 miles at below 3000 revs is a good idea and I wouldn't extend the revs beyond 4K until 1000 miles. But I would definitely buy an extended warranty.
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I haven't had a chance to look at the video yet, BUT.....
When opening EPC and looking at the cylinder head there are special notes attached to it stating that the part number fitted from factory is no longer available and to use an alternative part number instead.
Additionally the exhaust valves have had a supersession on the part number also...
So I guess the head and exhaust valves have been modified.
Three years ago MB also released a "KIT" part number:
We would like to make you aware of the creation of a parts kit for the replacement of the cylinder head on M 260 petrol engine. The parts kit comprises of a complete cylinder head, head gasket and intake manifold seals, all other parts for the repair should be ordered separately.
When opening EPC and looking at the cylinder head there are special notes attached to it stating that the part number fitted from factory is no longer available and to use an alternative part number instead.
Additionally the exhaust valves have had a supersession on the part number also...
So I guess the head and exhaust valves have been modified.
Three years ago MB also released a "KIT" part number:
We would like to make you aware of the creation of a parts kit for the replacement of the cylinder head on M 260 petrol engine. The parts kit comprises of a complete cylinder head, head gasket and intake manifold seals, all other parts for the repair should be ordered separately.
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Hi Forrester the reasoning from MB was that they only replaced the head so the engine cylinders etc are already worn in. I was not entirely convinced to be honest.
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Don’t bother.
He’s speculating and barking up the wrong tree re the cause of the valve and seat pitting.
M-B have already stated why the problem is occurring in a TIPS.
Let’s not continue to set hares running by suggesting there’s a problem with the head.
This is a symptom. What is the cause? As it’s not happening on with the same frequency on other engine variants.
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No it is not a symptom. It’s clear you aren’t an engineer! 😂
Not sure what you are trying to say here.
The root cause is incorrect tolerances of the valve stem to guide interface, leading lateral forces and wear as explained in the TIPS document.
So please stop propagating the fallacy that it’s a problem with the cylinder head!!!
Valves and guides are the cause/problem.
It would have been useful to have said this rather than expecting a transfer of knowledge by osmosis.
Of course not. How could I afford an A45s 😂
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It’s said in this and other related threads!
But it’s also useful not to keep propagating suppositions on the forum!! 😂
Without propagating his assertion. Do the engineers among us agree with MB that this is the root cause as people have still had their A35 engine develop the fault again.
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