Mercedes CDI Injector leak – Honda washer/seal alternative

You may have read previously either here or on the web about the use of the Honda Accord 2.2 Diesel injector seals in applications for Mercedes CDI diesels.  Sprinter, Vito, E320, C220, C 320 etc.  Here is an instance that really benefited from the use of the alternative sealing washer.

Honda Injector Seal

Honda Accord 2.2 Diesel Injector Seal

I had one of the courier fleets T1N 4 metre Sprinters in for repair due to a chuffing injector.  Unlike most common ‘Black Death’ related failures this one had just decided to spray diesel everywhere under the bonnet without any prior warning or over-time buildup of coke around the injector. Previously the other 3 injector seals in this engine had been replaced with Honda types and this single remaining one (No.2 Cylinder) was an original Mercedes OEM seal installed at the same time as the others, simply because I had no more Honda parts available.

On removal of the injector (slacken injector hold down clamp bolt and run engine to normal operating temperature – this often unseats the injector allowing relatively trouble free removal) It was discovered the seat was scored and pitted. The seat was recut then lightly faced with a hand reamer / face cutter tool then checked with a mirror and torch.  I knew this seat was good last time I replaced the seal so there had been a problem with blow by gasses cutting the seating face.

Laser injector seat cutter tool

Laser 4597 Diesel Injector Seat Cutter Set

So now all seals have been replaced with Honda parts and the van is once more good-to-go!   This engine, along with the van itself has covered over 500,000 hard courier miles and although the piston rings/bores are now nearing end of life (increased crank case pressure) it still sounds sweet and runs like a train.  Also interesting testament to chipped and tuned engines and their longevity, this one was performance chipped from new and at half a million miles running its hard to say that it has in any way been detrimental to its life span – an interesting point of note.

I have photographed the Honda part (injector seal) above in its original packet for ease of identification and obtaining the part should you wish to use the alternative copper sealing washer.  They look slightly thicker and are definitely made from a softer more malleable material than the OEM Mercedes units – My own view is that this ‘softness’ assists in sealing to irregular hand cut/cleaned seal faces and seats better than the harder MB equivalent washers.


Mercedes Sprinter engine 500,000 miles and still going strong…



20 thoughts on “Mercedes CDI Injector leak – Honda washer/seal alternative

  1. In my constant struggle to keep my abused 313 CDI Sprinter running I found it sometimes impossible to get a good result from the mercedes copper seals. Now I “glow’ the new seals first to get maximum softness and it seems to work a lot better.
    ‘Glowing’, using a small soldering torch( or a small kiln if possible) heating them till red-hot (650ºCelcius) .

    1. Hi Ed, I do wonder if refacing the seats could be the best way to go (but you may have tried that already). Still, if it works then its really worth a mention.
      Thanks for the tip,
      All the best

  2. My W202 2.2 cdi (W reg) is having an issue on the fourth injector. It suffered from a case of Black Death prior to my ownership and as such, had to have 2 injectors reseated. Now this misbehave my problem lies. The forth injector has just started to blow back. The garage that carried out the work have recut the injector seat and now there is too much space for the copper washer to seal. The MB garage have said it will need a new cylinder head, however, I reckon a thicker washer would do the trick. Thoughts on using the Honda washer?

    1. Hi Curtis,
      The Honda washer is slightly thicker, so yes its a possibility. I know also that not often known Mercedes have part numbers for thicker copper washers/seals for use where material has been removed in a recut. I do not have the part number, but know of their existence. Perhaps a friendly dealer parts department can help you out.

      All the best

      1. So didn’t you use the mb injector bolt then or a Honda bolt as it was a Honda copper seal. ?

      2. So as I only have on leaking injector “the first one” I’ve bought an Honda diesel injector seal slightly thicker like you said. would the injector bolt that comes with the seal be ok to use with the Honda injector bolt so “Honda seal/ MB injector bolt ?

      3. 1.52mm MB copper seal
        2.4mm Honda copper seal
        Would it matter if I just used one Honda copper seal on my leaking injector as it’s the only one leaking? Thanks

  3. I am not finding those “Honda Accord 2.2 Diesel Injector Seals” anywhere… Where did you purchase them from? Thank you.
    I have a 2006 Sprinter leaking around a couple of the injectors, and after reading what your recomending I think I should try the Honda Seals.

  4. The USA dealers can’t seem to find these by part number and are not familiar with the 2.2 diesel accord. I assume this is a Europe market engine? If you can verify what market you are in or give me a dealer name or email it would be greatly appreciated.
    Thank you

    1. Hi Wayne,
      Ebay could be your route. There are a few UK sellers that ship internationally and this would be the way to go if you can afford to wait for delivery.
      All the best

      1. Thank you Steve. The eBay site I found would not ship intl but I will just have to keep looking while I wait for my injector puller to show up.

  5. Hi Steve I have a Vito CDI 115 2004 panel van. It started chuffing and resulted in black death.
    My number one injector started leaking. I took the vehicle to a recognised MB repair shop.
    They failed miserably.The repair lasted just three months. Scouring through Google for DIY answers to black death, I came across Mercedes Gen-in and Mr Steve Ball.
    The replacement of the shrink bolt and cleaning out the bolt threads and debris blown out of the threaded bolt holes to make sure the bolt bottomed out when torqued down. The lapping in of the injector seat face The suggested replacement of the copper washer with the Honda 2.2 Accord.
    I phoned the garage that carried out the repair and was told bring it back your repair has a 1 year guarantee. I quizzed the forman regarding replacement of the shrink bolt. No we pull the injector out slip a new washer in and and that’s it, repair complete.
    I decided that it was pointless going back and carried out the repair myself.I bought the bolt the OEM copper washers and the Honda washers. lapped in the seat face and put it all together using the thicker HONDA washer what a pleasure . The repair is still going strong after a couple years I managed to T-BONE a clown who jumped the stop street and give the front half of my van fat hair lip. The insurance assessors wrote the vehicle off. Due to the rust and corrosion.
    I did drive the vehicle home due to a pile of tools in the back and the presence of vulture tow and ambulance drivers who don’t take no for an answer.
    I have bought another second hand Vito with a rough idle due to what I am told by a diesel mechanic acquaintance, is too much diesel being delivered through a faulty injector.
    I brought up the previous repair experience of using a Honda Accord cu washer in my first Vito and he brought up fact that the injector spray pattern would differ from the Mercedes washers due to the thicker HONDA washer
    The thicker washer would /could create lubrication problems on the cylinder walls.
    Performance would /could be affected.
    I am a refrigeration and air conditioning mechanic by trade and a DIY’er by nature.
    I understand copper as I make flares from time to time.
    First rule of a good flare, DO NOT crush the living daylights out of it. Just create the shape. Let the tightening do the sealing.
    A thicker washer makes far more sense to me. More copper thickness /volume to take up the irregularities on the seal face.
    I would appreciate some feed back on my diesel mechanics worries.

    1. Hi Roy,

      Thanks for the comment, up to my neck in stuff so little time to dedicate to the website as I might have liked at the moment, however to respond to your question:

      The Honda copper washers are by far more ‘malleable’, they appear almost annealed compared to the genuine MB ones that are very hard stamped and will not compress much, this you can tell. The complient softer material as you point out, in my view moulds better in the action of of tightening so is a superior repair to less than perfect surfaces whether due to erosion, corrosion or just the inadequacies of hand reaming. Either way not scientifically proven – just more common sense and basic physics.

      The comment regarding penetration depth of the nozzle holds some technical value. However if you think of the action of cleaning /refacing the alloy seat this would remove some material anyway and depending on the amount of work required would push the nozzle further into the head, a thicker washer simply compensates for that as you can imagine. You have to also remember that often engines undergoing this work have clocked up 100k plus in mileage. If the injectors are the originals, please don’t think the injector spray pattern will be anything like the day it left the factory anyway – so there is an uncontrolled variable to consider when digging too deep into the science and text book stuff.

      The injectors positional change into the head we are considering here is sub 1mm and in my opinion and experience the naked truth is, it makes little difference. No doubt others will argue – like what what tyres are best!

      All the best

  6. Hi Steve
    I really appreciate your time taken to reply and your valuable input.
    I believe you hit the nail on the head with every point regarding the Honda washers and the difference in the slightly thicker clearance.
    Every point you make makes sense.
    You end with same clearances, but a more compatible and forgiving washer.
    I will be quite happy to replace with Honda washers after I remove and replace the injectors shortly to find and replace the faulty one or ones amongst the set in my latest van.

    Many thanks and Best Regards,
    Roy Vickers.
    South Africa.
    PS Many thanks for a great forum.

  7. Hi Steve, I appreciate you’re a busy man but would value your advice before fitting a new set of injectors to my 2007 311 CDI, they’re the Bosch Piezo type.

    Is the Honda Accord seal swap still applicable to the newer 646.985 engines? (torque to 7Nm + 180 deg?)

    Injector coding – is this MB main agent only or do I need to find a local mechanic with a specific electronic device/software? Do i just record the number etched on the top plastic collar from each injector and tell the coder which cylinder they went in? Will it run without coding? MB are 40 miles away from me.

    Thanks again for your much valued help


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