Diesel Injector Pump Leak info please

[steve kane]

Hello again everyone, well were still plodding around in our 1995 C250D but all of a sudden its again developed very poor starting. A peep under the bonnet revealed a diesel leak from under one of the Splined connectors on top of the Injector Pump where the Injector Pipes exit and a small amount of Air in I think the return pipe. I can see that these Splined Connectors are secured with overlapping plates which slip over the Splines and are themselves bolted down with a Torx type screw. I guess that there will be a Rubber Seal on the Connectors where they screw into the Pump Body and I wonder if anyone on the Forum has had any experiance removeing them, if the Rubber Seals are readily available, and where on earth do I get hold of the Splinned Socket? Quite apart from the annoying leak Im hopeing that this is also where the air is being drawn in as I replaced (I think?) every Rubber Fuel Line Seal the last time I had Air in the Fuel Lines.
Steve.

 

[Parrot of Doom]

A leak there shouldn't cause many problems starting, unless its gushing out. Have you checked the fuel lines around the fuel filter and pump, and also the o-rings on the main filter and the pre-filter?

As for the delivery valves, you need a special socket from Mercedes to remove them. They are sealed with a copper washer and an o-ring and IIRC require a specific torquing value. I've also heard some scary tales about disturbing the valves once the lines have been removed.

 

[steve kane]

Many thanks for the reply, its a slow drip from under No 1 Delivery Valve, and I wonder if as well as leaking out fuel, its drawing in air at this point too? but who knows, there are so many pipes involved its a job to know where to start and earlier this year I replaced all the fuel line O rings, its an obvious leak on the fuel pump and I think I should go for it first, I wonder if one of those Bosch Service Centres would just pop another O Ring in for me, with the correct socket It looks like a simple enough job(?)
Steve:roll:

 

[watsone91]

The fuel pump in the c class diesel was a Lucas part and it tended to leak at the joint between the electronics and the mechanical parts of the pump.
It will leak when it was cold and would stop leaking when the engine warmed up i had this car for seven years and never knew when it would leak it went four years without a drip until i had my mono block drive cleaned it then proceeded to to shame itself on a regular occasion i could not get anybody to remove the pump and service it.
This meant i had to trade in for a newer car(c250 tdi 1998) Mercedes must have changed the pump in this car as it has not leaked at 80,000 miles but i will keep my eyes peeled .

 

[Parrot of Doom]

I don't think it can draw air in through there while running, the pressure is too high. The air tends to get in before the pump (certainly on the E300TD anyway, which is a similar design IIRC).

Those valves are always slightly damp on mine, they don't drip though. I have the tool, washers, and o-ring in a cupboard, I can never get around to doing it. Too lazy I guess as it means removing the intake manifold

 

[steve kane]

Many thanks for your help everyone, On our 5 cyl C250 according to the Haynes WSM its fitted with a Bosch Inline Injector Pump, apparently the 4 Cyl models have a Lucas Rotary style pump. Its really just such a pain in the backside this Air Leak business as the leak is always so hard to track down and esp as I have only 6 months ago replaced the O Rings on all the Pipes in the engine bay and I'm fairly sure I also did the one behind the Fuel Shut Off Valve too. I can see the logic of Air not being able to get into the system at the Injector Valves due to the pressure but as I said before, its an obvious fuel system leak and I wonder if the pump "sucks" as well as blows below the valves, drawing up fuel? but I suppose I'm clutching at straws. Once the car starts it runs just fine, but the tell tale air bubbles can be seen dashing through the middle plastic pipe of the 3 that connect to the Fuel Filter Houseing, and it looks to me that this is fuel returning to the shut off valve on the side of the Injector Pump? I wonder if I can find the Fuel System Diagram that's on the site somewhere? I'm off to have another "stand and stare" session. BTW Parrot what size is that Splined Socket you have that fits the Valves, was it easy to find?
Steve.

 

[Bolide]

AFAIK it's a C-shaped socket - ie there's a cut down one side to allow you to slide it over the injector pipe

Have a look at these two sites for MB-specific tools

http://www.samstagsales.com/mercedes.htm

http://stores.ebay.com/Shermen-Auto-Tools

Nick Froome
www.w124.co.uk

 

[steve kane]

Well it seems to be good news, I unfortunately had to go to a fuel injection specialist with the correct 32 (33??) Spline Socket and watched him just unscrew the leaky delivery valve, the Rubber O Ring was flat sided and brittle, he just replaced the O Ring and left the Copper Washer in position, nipped the valve back into the pump and this evening, after sitting for a few hours the car started again without difficulty and I cannot see any Air in the Fuel Lines, so it seems clear that despite the logic of Air not being able to get into the High Presure Side of the fuel system, it clearly can, or perhaps when the engine is not running the leaky seals allow the fuel to drain away drawing in Air. Intrestingly the leak at the Delivery Valve was considerably less when the engine was warmed up. The US site refered to by Nick has the Hazet Socket, I copied the details below. Knowing what I do now, if I were replaceing elderly Fuel Line O Rings I would also do the Delivery Valves, they are very easy to do once you get hold of the Special Socket. I wonder if Mr Parrot would be prepared to hire out his special tool for a few quid plus postage??
" HZ 4556 617 589 01 09 00 HAZET special 1/2" drive socket with 33 teeth for removing and mounting the pressure valve holder on the injection pump of Mercedes-Benz diesel passenger cars 601, 602, 603, 605, 606, 615, 616, 617I will update again tommorow after leaving the car overnight and Im keeping my fingers crossed its still okay,
Steve.

 

[Parrot of Doom]

Interesting to know that that can happen. All the air leaks I've ever read about have been on the other side of the pump.

As for the socket, you may as well just buy it from the dealer, from memory it didn't cost that much more than a good socket. You're probably best visiting them, it may take them a while to find it on their computer.

I'd definitely do the rest if you feel confident enough, but do be careful not to disturb things on the pump.

 

[steve kane]

Well this morning after sitting untouched since yesterday evening this car started first time, so clearly the air was getting into the system via the leaking rubber O Ring on the Delivery Valve. I will try to source one of the sockets via Mercedes, and as I said before, anyone with Fuel System Air Leak problems would do well to change the delivery valve seals while there at it, its a very easy job once the manifold is off.
To explain it fully, First have a good clean around the top of the Pump, undo the Injector Pipes at the Delivery Valves and then useing the Special 33 Point Socket undo the Delivery Valves one at a time, there is a large spring under each Del/valve and on the Merc this can be left sitting in the pump when you unscrew and carefully lift out the Valve, change the O Ring on the valve you have lifted out and carefully sit the Del/Valve back over the Spring and screw down, the Copper "Crush Washer" has already been crushed and my "expert" just nipped the delivery Valve tight. I would do one valve at a time after removeing all the locking plates and perhaps cracking loose each delivery valve. Good luck,
PS Our leak started after experimenting with a less than 50% mix of Veg Oil and intrestingly the fuel system expert said that they feel that for some reason the Veg Oil seems to attack the old Rubber Seals, so this might be worth bearing in mind if your thinking about giving Liddles Cooking Oil a go!!
Steve.

 

[steve kane]

Just a quick "update" well the car is now just fine, the replacement of the Injector Valve O Ring cured my Air in the Fuel System problem, I had prev changed the Fuel Line O Rings but I would suggest that persistent Air Leak problems might well be due to very slight leaks in the Injector Valves.
Despite what Mr Parrot says about the easy availability of the Special Socket required for unscrewing the Valves, I found it virtually impossible to buy the Special Tool (Merc quickly realised that I was not a Legitimate Motor Dealer via the VAT number I had to supply and refused to sell me one!) and in the end spent a truly obscene amount of money to Import one so that I don't have to go to Rip Off Fuel Injection specialists and watch them change the equivalent of a single Spark Plug and charge £40 cash for the privilege of changing a Single Rubber. If anyone wants to borrow this Socket I'm happy to lend it out via the Post for a small donation to the "Return Mr Kane to some sort of Solvency fund" Its an easy job and worked just fine for me,
Steve.

 

[oilychariot]

special hazet socket

Hi there Steve, I have the same problem re. air being draawn into the system when the car is stopped. The hotter the engine/longer it has been running/the thinner the svo mix the worse the problem.
A right royal pita!
Car (1990 124 300td) has run for 22,000miles on svo before leak began, usually 95%, 90% when frost in the air. Shell V-Power diesel works well as the 5%, has highter cetane rating and you don't mind paying £1.10 a litre when you're using so little.
Car has covered >250,000miles so not overly concerned, but the job needs to doing if my sanity is to return.
Imho the 124 quality slipped steadily, the 87-91 model years representing the best cars. With the 603 engine the estate comes close to the ideal ute.
Let me know if the tool's still available for hire. Thanks.

 

[steve kane]

Yes of course, I have replied to your email and if you let me have your address I will pop it into the Post to you,
Steve.8)

 

[apoppyc]

Me too

Hi steve,

I think you have just saved my sanity with your post on this problem, my 98 c250td developed the same problem of not starting in the morning but onece started it did so just fine for the rest of the day. On inspection my local mechanic noticed a fuel leak in one of the lines leading to the pump and of course assumed this was where air was being drawn in. He relaced the line but the problem persisted so he then canged the stop valve ? but the air was still there. Then trawling this site i found your post which i feverishly printed off and will be rushing to my mechanic on monday morning. Hopefully this will be it . Thanks to all who had something to say on this problem.

:mrgreen:Adam.

 

[C250TDSportAuto]

Mee too

This could be the problem I'm having. I've done the fuel filter, pre filter and o rings on the lines, but do have a leak on 2 of the delivery valves, and still have the starting problem after the car's been stood a while.

I am slowly losing my sanity with this problem and I'd happily pay to hire your splined tool, If you still have it Steve.

Found this while i was trawling. http://www.mercedesshop.com/Wikka/OM602InjPumpFuelLeak?show_comments=1 . Looks useful.

 

[sharky1]

I had the same problem and still do, I have persistant leaks from 2 delivery valve holders, I purchased complete new kit including o rings washers and springs, used special spline tool and removed all valve holders replacing o ring-copper washer & spring in each, re fitting valve holders by delicately rocking and screwing them from side to side so everything would fit snugly, I then Torqued all valve holders to 35Nm as recommended. I re fitted everything back together and after considerable false starts merc started with plenty of power and idled perfectly but unfortunetly fuel leaks appeared from base of return valve holders just as before. I removed everything again cover, accelerator assembly, intake manifold etc etc etc, I removed all collars -valve holders again checking that everything was fitting perfectly and alligned properly paying particular attention to proper seating of springs, I re- screwed everything back in place and re torqued to specified pressure & fitting retaining collars but still no joy and have done this 4 times already, which has been time consuming and soul destroying when the outcome is sadly still the same?
Don't know what I am doing wrong if anything, I am wondering what I can do to resolve this major problem?

 

['89 250TD]

IP valve MB socket loan - thanks Steve!!

Thanks Steve for the prompt despatch & loan of the special MB socket & the helpful tips along the way... hopefully I'm all set for the MoT now...
Regards
Mark

I found it virtually impossible to buy the Special Tool (Merc quickly realised that I was not a Legitimate Motor Dealer via the VAT number I had to supply and refused to sell me one!) and in the end spent a truly obscene amount of money to Import one so that I don't have to go to Rip Off Fuel Injection specialists and watch them change the equivalent of a single Spark Plug and charge £40 cash for the privilege of changing a Single Rubber. If anyone wants to borrow this Socket I'm happy to lend it out via the Post for a small donation to the "Return Mr Kane to some sort of Solvency fund" Its an easy job and worked just fine for me,
Steve.

 

[oilychariot]

Hi Steve, sent you a pm a whike ago but have heard nothing back - if you read this please contact me. Thanks alot.

 

[steve kane]

Delivery Valve Spline Tool

Hello Oily(??) sorry if I did not reply, a personal message to my email address should get through though.
If anyone still requires the Spline Tool for removeing the delivery Valves please contact me again, the old one was lost/syolen in the post and its been quite a job to locate another, one is today (9th Sept 08) on its way from Germany and will be here in a week or so, and any forum member is again most welcome to borrow it for a very small contribution towards its exhorbidant cost!!
Steve.

 

[steve kane]

Hi Steve, sent you a pm a whike ago but have heard nothing back - if you read this please contact me. Thanks alot.

Hello Oily, just tried to email you a private message but you have elected not to recieve them,,please feeel free to contact me,
Steve.