The Dreaded P2036 (P0410) Issue CLK 230

[Dean Fletcher]

From the other side of the fence my 3 MBs have cost in total (excluding fuel and consumables) around £2000 between them in 4 years.
Major costs were:
R129 central locking pump (£200)
R129 engine wiring harness (£500)
R129 rear window (£300)
W210 Aircon compressor (£300)
W210 radiator (£300)
W210 battery (£75)
Misc bits and pieces and oils account for about another £300.

I'd not call that expensive across 2 X V8s and a V6.

I'd be more than happy to spend circa £666 over 4 years. I'm hoping mine gives me some trouble free years to come. I need to get the breaks pipes replaced at some point and new left bushes done but them jobs can wait a little.

 

[Dean Fletcher]

said it before and i will say it again, Mercedes are unreliable due to sites like this one !!!!!
I will expand, people do not come on this site to say how fantastic their Mercedes is and that it has cost nothing in their ownership, people come to sites like this because they have a problem with their car.
I have to admit, i frighten myself every time i read through issues people are having and then expect my own Mercedes to have the same fault, and i start to look for faults that are not there, just because i read someone had this issue, or that issue.
The "M" class was really slated due to what was seen as poor production and reliability, but how many people had one that never went wrong ?, we will never know because they will not post information like that, i suspect it is true of the entire range.

Opps, Rant over, back to normal (what ever that is)

My om651 engine timing chain

 

[Oldspanners]

Hi LostKiwi and Dean

Firstly .. I don't believe this car has had the cam sensor oil blockers, but someone had the good sense to have the electrical connector facing 7 o clock position and it has the wiring loom headed towards the top of the engine, so at least gravity doesn't carry the oil along the harness (thank god) and this is the reason the connector was half full .. the oil has nowhere to go and just created an oil bath.

Ouch Dean !! I feel your pain .. I really do. Just as well you found out about the ECU plug. I would hate to think what it would cost you to keep going back for diags, not to mention "some" mechanics who would probably tell you "Your thung filing spanner grommet is defective" and charge you the earth to replace things that never needed replacing.

I also found out after purchase, that the previous owner removed the Engine Management bulb. He must have got sick of the bulb draining the battery cos it was on so much hahaha

Unfortunately the oil wicks in through the stranded copper wiring, although gravity will aid it. The cam magnets and blockers are easily fitted and the sooner the less oil will have entered the harness and the less consequential problems will occur.

 

[clk2000]

said it before and i will say it again, Mercedes are unreliable due to sites like this one !!!!!
I will expand, people do not come on this site to say how fantastic their Mercedes is and that it has cost nothing in their ownership, people come to sites like this because they have a problem with their car.
I have to admit, i frighten myself every time i read through issues people are having and then expect my own Mercedes to have the same fault, and i start to look for faults that are not there, just because i read someone had this issue, or that issue.
The "M" class was really slated due to what was seen as poor production and reliability, but how many people had one that never went wrong ?, we will never know because they will not post information like that, i suspect it is true of the entire range.

Opps, Rant over, back to normal (what ever that is)

I would disagree with your first comment joderest .. Mercs are not unreliable due to sites like this, but rather maintenance neglect the majority of the time and in fact, I would say sites like this actually help the lay man. I would hate to think how many vehicles would have seen a scrapyard without the assistance and knowledge contained in these sites. They always used to say B.L. were unreliable and as an ex BL trained mechanic, I can say in all honesty that owners even back then tried to sue for new engines due to the fact they couldnt be bothered to check their oil levels as "it is a Service item and YOU service my car, therefore your responsibility" haha

 

[ajlsl600]

None reported because there haven't been any (but was too scared to say out loud...)

very wise too!!!!!

 

[ajlsl600]

can someone explain more re cam sensor oil blockers , would like to see where they go and what they look like

 

[Uncle Benz]

can someone explain more re cam sensor oil blockers , would like to see where they go and what they look like

They are just a short section of loom with a male plug on one end and a female on the other. In the middle each wire has a solid terminal block, so the copper strands don't pass straight through, and therefore the oil cannot pass that point. Arguably you could create the same thing by stripping back original wire, put a big lump of solder on and heat shrink over it. The merc part definitely works though.

 

[Oldspanners]

can someone explain more re cam sensor oil blockers , would like to see where they go and what they look like

The problem is the cam magnets leak oil internally into the connector which then wicks through the stranded copper wire into other parts of the wiring harness, notably the after cat O2 sensor and the rear ECU plug.
The blocker is just (an expensive £52 for the pair) piece of solid wire which plugs into the cam magnet and into the wiring harness to prevent the ingress of the oil when the magnet oil seals fail again.
Hopefully the pictures show this.
On another thread I remember someone stripping the cam magnets and modifying them to prevent this.

 

[ajlsl600]

They are just a short section of loom with a male plug on one end and a female on the other. In the middle each wire has a solid terminal block, so the copper strands don't pass straight through, and therefore the oil cannot pass that point. Arguably you could create the same thing by stripping back original wire, put a big lump of solder on and heat shrink over it. The merc part definitely works though.

ah , understood

 

[ajlsl600]

The problem is the cam magnets leak oil internally into the connector which then wicks through the stranded copper wire into other parts of the wiring harness, notably the after cat O2 sensor and the rear ECU plug.
The blocker is just (an expensive £52 for the pair) piece of solid wire which plugs into the cam magnet and into the wiring harness to prevent the ingress of the oil when the magnet oil seals fail again.
Hopefully the pictures show this.
On another thread I remember someone stripping the cam magnets and modifying them to prevent this.

ah understood x2 £ 52 a bit stiff ,for what is ,it seems a maker screw up ?

 

[Oldspanners]

ah understood x2 £ 52 a bit stiff ,for what is ,it seems a maker screw up ?

That's for two, here's the list and prices from 2 years ago.
Genuine Mercedes-Benz OM271 Camshaft Magnet Wiring Harness A2711502733
Quantity 2: £51.98
Genuine Mercedes-Benz OM271 Engine Camshaft Magnet Seal O-Ring A0109972348
Quantity 2: £13.70
Genuine Mercedes-Benz OM271 Engine Camshaft Magnet Grommet A2710510032
Quantity 2: £3.98
Genuine Mercedes-Benz OM271 Engine Camshaft Magnet A2710510177
Quantity 2: £74.64
Total: £144.30
All that was needed was a little blue thread lock, some cleaner, took me about 20 minutes to clean and replace and about another six months cleaning up the oil in the wiring harness.
Was a recall in the USA of course!

 

[ajlsl600]

what a surprise. its just common sense to organise that any harness that could end up with fluid in it, or is known to have this issue is orientated so that the fluid would have to run uphill .. before entering anything vital .. i was taught that for electrics some 40 yr ago !!! and it seems evident from the parts avail that benz know about the issue and are simply just happy to cash in on it ... (cam harness oil blockers _) i am guessing they are fitted as std on new cars that are prone to this issue ? but will not be surprised to learn thats NOT the case ..

 

[LostKiwi]

To be fair to MB the oil does need to go up from the connector but capillary action creates the issue where the oil can migrate through the loom. The blockers stop the capillary action effectively preventing the oil creating an issue.

 

[clk2000]

Ok ... Cam magnet and sensor has arrived and ready for fitment. I have been looking at the oil arrestor cables and it seems to me they are just cable extenders ?
I have been thinking about this wicking issue for future reference and I'm thinking, maybe the possible alternative way forward would be to drill a small hole in the electrical connector on the magnet unit ? .. just seems a more viable permanent fix to me on the grounds that if the oil can't pool .. it can't wick as there wouldn't be enough flow to do so.
This may in future mean that if it should ever leak again, it would be more messy but also a good indicator of problems also ... any thoughts on this crazy idea of mine ??

 

[Oldspanners]

Ok ... Cam magnet and sensor has arrived and ready for fitment. I have been looking at the oil arrestor cables and it seems to me they are just cable extenders ?
I have been thinking about this wicking issue for future reference and I'm thinking, maybe the possible alternative way forward would be to drill a small hole in the electrical connector on the magnet unit ? .. just seems a more viable permanent fix to me on the grounds that if the oil can't pool .. it can't wick as there wouldn't be enough flow to do so.
This may in future mean that if it should ever leak again, it would be more messy but also a good indicator of problems also ... any thoughts on this crazy idea of mine ??

The blocker cables are just solid wire with male and female connectors so the oil if/when it ever leaks again will go no further. Just fit them and forget about it.
The only problems you could have is from oil that has entered the harness this will manifest itself at the lowest point, the after cat O2 sensor at the bottom of the bell housing and the rear plug of the engine ECU oddly. Clean it up with contact cleaner and a blast of compressed air if its there.