Terrible MPG on Kompressor

[Oldspanners]

This is one of a number of threads that discuss the cam magnet oil leak and the consequences as the oil heads off around your wiring loom to cause poor connections at any number of connectors and generally mess up your engine so I will add my two cents here.
There are loads of these engines out there and its a question of when not if you are going to get caught by it. MB have invented the retrofit additional wiring loop to prevent the oil getting into the main loom but after years of main dealer servicing never has the fitting of these been recommended for the car I'm working on. That's shameful customer service in my view. They knew it could be an eventual costly problem -£2500 quoted in this case - wiring loom, ECU, sensors etc etc.
I've got O2 sensor error and this appears to be the favourite destination for the oil according to most threads. At the lowest point I guess this is natural what with gravity and all. I cleaned up the connector but I'm going to replace the sensor anyway. There's a larger, squarer wiring connector located immediately above the round post-cat O2 sensor connector and when I opened that one up I nearly got an eye full of 5W-30. Its true - always wear safety glasses.
There is a thread on MBWorld I think, where someone has fixed the cam magnet leak rather than replace the things at £loads each. I have followed suit and hacksawed off the three aluminium rivet heads which hold it together. The thin silicone washers inside are what have failed and let the oil past. I have added a suitable flexible gasket cement to each side of these and put the sandwich together again - my expectation is this repair makes it considerably better than the original device - I will update in the future when I'm proven wrong (or right). The O-ring behind the cam magnet needs replacing but I can't be doing with paying 6 or 7 quid for something that costs less than $2 stateside - why is it we are always being fleeced in the UK ? This too will get the gasket cement treatment.
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Wish I had thought of that and the wiring harness blockers are just solid pieces of wire with the male and female connectors. I seen some people cut open the harness and solder the braided wire solid to stop the oil.

 

[ErnieC]

Wish I had thought of that and the wiring harness blockers are just solid pieces of wire with the male and female connectors. I seen some people cut open the harness and solder the braided wire solid to stop the oil.

Cute. If only there was a bit more spare cable so it could be made to rise upwards after the connector to the cam magnets. But your comment got me thinking and prompted me to don my dressing gown and head torch and have a butcher's under the bonnet - neighbours are away so little danger of appearing eccentric. Now what I found was there is just a possibility that because the connector on the cam magnet is the male part and the cable has the female half, it might be possible to apply some electrical tape around the connector such that if the sensor leaks oil it would run over the tape and onto the outside of the female connector half instead of the current dumb design which channels the oil into the wiring. I'm going to try that anyway as it will give me early warning if my cam mag rebuild has failed ie oil dripping all over the shop. Where can I tie my horse in this forum ?

 

[Oldspanners]

Cute. If only there was a bit more spare cable so it could be made to rise upwards after the connector to the cam magnets. But your comment got me thinking and prompted me to don my dressing gown and head torch and have a butcher's under the bonnet - neighbours are away so little danger of appearing eccentric. Now what I found was there is just a possibility that because the connector on the cam magnet is the male part and the cable has the female half, it might be possible to apply some electrical tape around the connector such that if the sensor leaks oil it would run over the tape and onto the outside of the female connector half instead of the current dumb design which channels the oil into the wiring. I'm going to try that anyway as it will give me early warning if my cam mag rebuild has failed ie oil dripping all over the shop. Where can I tie my horse in this forum ?

The problem is the oil "wicks" up the strands of the cable and only a solid wire blocker will stop it or stop the leak at the source by changing the magnets or indeed do as you have.

 

[John Laidlaw]

What part of Scotland are you in? I'm near Edinburgh and have an iCarsoft scanner. Free to Forum members.

Think you meant to reply to trueblue1872- I’m the truemaroon1874 type!

 

[Wighty]

Just checked the M271 ECU (both plugs) and they are totally dry ...Phew ! The panic that has gripped Chez Wighty since I read this thread has disapated . Just waiting on the blocker wires to arrive and be fitted

 

[LostKiwi]

Just checked the M271 ECU (both plugs) and they are totally dry ...Phew ! The panic that has gripped Chez Wighty since I read this thread has disapated . Just waiting on the blocker wires to arrive and be fitted

If you took everything posted on the forum to heart you'd never drive the car for fear of something breaking. Whilst it's wise to be aware of these things don't panic about them as in most cars it's a non-issue. Forums distill problems by the very nature that we only hear from those with issues but no one ever posts about nothing breaking on their car today/this week/month/year.

 

[daibevan]

If you took everything posted on the forum to heart you'd never drive the car for fear of something breaking. Whilst it's wise to be aware of these things don't panic about them as in most cars it's a non-issue. Forums distill problems by the very nature that we only hear from those with issues but no one ever posts about nothing breaking on their car today/this week/month/year.

Only if they don't believe in tempting fate.

 

[LostKiwi]

Only if they don't believe in tempting fate.

Would make for a pretty boring forum!

 

[Wighty]

If you took everything posted on the forum to heart you'd never drive the car for fear of something breaking. Whilst it's wise to be aware of these things don't panic about them as in most cars it's a non-issue. Forums distill problems by the very nature that we only hear from those with issues but no one ever posts about nothing breaking on their car today/this week/month/year.

Very true buddy , but when it's a fault you haven't heard about on your own car model and never checked it before you have to go up a gear and take action

 

[Wighty]

The 2 wire "blockers" arrived today , just fitted them and I decided to wrap them around the engine lifts because I was worried that if I ziptied them and the ties broke they would be too close to the drive belt .
It does seem ideal as the connections are a bit tight.
Also does anyone know if there is any way they can be plugged in the wrong way around ?

 

[LostKiwi]

is any way they can be plugged in the wrong way around ?

Not unless you're exceedingly 'creative' with a hammer...

 

[Wighty]

Not unless you're exceedingly 'creative' with a hammer...

Excellent , I did take a lot of care checking which way went where , so I must have got it right first time (that's a first )

 

[Wighty]

Just checked , you can't wire them wrongly . I ziptied them to the fron of the engine lift rings rather than wrapping them around the rings , less strain on the connectors . More importantly I'm happy

 

[Blobcat]

Not unless you're exceedingly 'creative' with a hammer...

I've seen 15 way D-Types installed the wrong way around... individual responsible was a larger gentleman, he said they were a little tight but went in ok...

 

[LostKiwi]

I've seen 15 way D-Types installed the wrong way around... individual responsible was a larger gentleman, he said they were a little tight but went in ok...

If there's enough of a will.....

 

[ErnieC]

The problem is the oil "wicks" up the strands of the cable and only a solid wire blocker will stop it or stop the leak at the source by changing the magnets or indeed do as you have.

Well I have a few miles covered now and my reconstructed cam magnets are just fine - I added the electrical tape around the protruding male connector and the top of the female connector and this has stayed well stuck so I am almost regretting coughing up for those blocker wires which, morally at least, Merc should have fitted FoC. My conclusion is that the cheap(skate) solution to this issue is a bit of electrical tape to shield the wiring harness from swallowing any oil fed from a defective oil seal in the cam magnet. For the tape to adhere well of course the cam magnets need to be completely oil-free and the strip down and application of some gasket cement, as previously described, to a device which has no moving parts and should outlive the car many times over is easily done and recommended.