Valve & head gasket confusion

[Dexter]

I have been pouring over my extensive main dealer service history in the hope that I might see that the head gasket job (e280 w124 estate) had been done by the previous owner.

Among the items listed and this is exactly how it appears is:

01800202 Timing gear cover remove and install, seal
(cylinder head cover removed)
price £460.60

Now I have a good idea that it was a leak to the upper timing case that w as dealt with so I am bemused as to why the head had to come off! But if it did then is the gasket replaced as a matter of course? which does seem the logical thing to do.

I then looked at the parts listed and there were two gaskets:
104 015 02 20 at £3.97 and 104 010 21 30 a gasket set at a whopping £32.02

My hopes were raised that this was indeed a head gasket but I learn that this is in fact a Valve cover gasket???????

Does anyone have any idea what job the dealership did on my car and why they might have taken the cylinder head cover off if not to replace the head gasket. Indeed, what is the merit of having a new valve cover gasket?

Grateful

 

[television]

Leaks from the timming cover were common place. The rocker cover has its own gaskit, it is possible that the rocker cover was over tightened in an attempt to stop the leak, often hard to see where oil is coming from.Once over tightened it must be replaced.

Malcolm

 

[Bolide]

280 oil leaks

The 280 (and, I assume, 320) engine has a basic flaw that leads to a leak from the head/block join by the front timing chain cover. It's curable by removing the cover, installing a new gasket & refitting the cover. From your description it appears this is what the MB garage did. They removed the cylinder head cover (rocker cover), not the head, and replaced the gasket when they replaced it

I have a suspicion that some of the "cylinder head gasket failures" we hear about are timing cover leaks. When oil is leaking in that area it can be difficult to say where from and why so the easy (and expensive) way is to do the cylinder head gasket & the timing cover gasket to cure the problem

That's not to say that cylinder head gasket failures don't occur, though

Nick Froome
www.w124.co.uk

 

[flagstaff]

i don't know, Nick: leaks from the timing cover are common, to be sure - but CHG weakness with the W124 24V engines are a given, admitted to by MB inasmuch as they redesigned the gasket when replacement 'became due'; not to mention the wealth of anecdotes by thousands of owners. i've experienced both faults, and the symptoms are very different.

the W124 24V cars are actually quite rare out there on the roads, when you take into account the ubiquity of W201s, W124 12Vs etc & etc. my guess is that many of them succumbed to the CHG problem in a catastrophic way.

 

[Bolide]

Headgasket

How would you say the symptoms differ? I've seen engines that were coated with oil (particularly on the exhaust manfold side), some that are wet and one that was bone dry. Without steam cleaning the engine & running it till a leak develops I'd be hard pressed to diagnose which problem it was on the spot. Is there a typical spot for the cylinder head gasket to leak?

As I said, I don't doubt the failures exist. I just wonder if all the leaks that were diagnosed as CHG failure were acccurately diagnosed

Nick Froome
www.w124.co.uk

 

[flagstaff]

yes, there is a particular spot on the gasket: for the gasket itself to be leaking, the oil channel (looking at the CHG as if it were flat on a table, with the timing chain end nearest you) at the left rear of #5 cyl would have breached and be throwing oil into the nearest water channel - which is *very* near. this would cause the oil in water scenario, obviously. it wouldn't necessarily cause oil staining on the engine. my E280 was bone dry in this area. MB strengthened the gasket on replacement items.

at the timing chain end, oil leaks out where the upper and lower timing chain cover meet with the cylinder head/cylinder block. this is because the soft gasket at this point goes hard over time, and shrinks/cracks; and oil runs out and back down the engine from here. if the job has never been done, i can see how at high mileage the whole engine will be stained with oil; but oil loss is the only symptom - with the CHG going, the symptoms are more alarming. maybe mechanics who diagnosed the CHG from just looking at the motor were thinking "well the miles are high enough to have allowed the front leak to stain everywhere, and these engines *all* lose their CHG at around 100,000 ... so ... "

the engine will leak from the front end, unless the soft gasket has been regularly replaced and resealed.

the engine will definitely lose the CHG .. regardless.

 

[Dexter]

Thanks Bollide and flagstaff for some in depth input.

I have since consulted my local MB service dept who confirmed leak from HG and lower timing case. In trying to identify urgency of HG job he suggested that oil/water contamination symptoms may never show in which case if I can live with the oil droppings............

I have also been told that all these cars seap of leak a little from the HG even after it has been replaced which is why I in the quotes I have obtained I have struggled to coax an indication of a guarantee for the work of the HG replacement in terms of no further oil leaks, longetivity or mileage. Now most common sense tells you to stay ahead of any problems but if the thing will always leak to some degree then I don't need to worry about it until the symptoms are more chronic.

Must confess some dissapointment with the car as researched fully the most desirable facets of the engine and spec. Punchy 6cyl with versatile abilities and acceptable economy the e280 seemed to be the one for me. Fact of the matter is unless you can find one that has had £1500+ spent on this gasket or that the thing is a liability - Are these good cars? I mean most 2nd hand motors would be fine after you have spent this ammount on them.

Grateful

 

[Dexter]

Arghhhh! since writing my latest musing someone else has said of my car 'oh those go on for ever'

Yes, if you replace every engine rubber, seal, gasket at an average strip down time of 5hrs! some of them twice over

Let me put that one amongst the other great marque myths:

'w124 - The last over the over engineered German cars'
'Bullet proof engineering and build quality'

Only as good as its weakest point in my experience.

Is the quality of your MB reflected by the ammount you have to spend on it?
or are we just caught up in some wistfull conspiracy based on our knowledge of the cost of these cars when new?

 

[television]

Many 124.s have gone their whole life with nothing more than servicing in the normal manner, we only get the few here that do have some problems now and again. I always loved mine and have missed it ever since I sold it as the steering wheel was on the wrong side.

Malcolm