ML Diesel injector problem

[television]

Dieselman will answer soon, he is the best on diesels that you can get

 

[JonWhitehouse]

Hello

I have noticed a problem with one of my diesel injectors. It hs developed a glass like black crust over its surface and the cabin now smells of diesel when the engine is running. I have looked all over this forum and found it to be a fairly standard problem.

From what I can understand from reading several posts the problem lies not with the injector but its seal to the cylinder head. Is this correct or has my injector got a possibility of leaking from its body ?

I was wondering if I could just purchase a new seal from MB and spend the time cleaning the crud off to remove the injector and simply replace its seal ? I should point out the build up has completely covered the fuel injector and electrical plug, it can no longer been seen.

Also my fuel economy is awful, around 17MPG ( urban ), is this a side effect of the leaking injector ?

Any advice greatfully received.

Jon

 

[panason1c]

Hello

I have noticed a problem with one of my diesel injectors. It hs developed a glass like black crust over its surface and the cabin now smells of diesel when the engine is running. I have looked all over this forum and found it to be a fairly standard problem.

From what I can understand from reading several posts the problem lies not with the injector but its seal to the cylinder head. Is this correct or has my injector got a possibility of leaking from its body ?

I was wondering if I could just purchase a new seal from MB and spend the time cleaning the crud off to remove the injector and simply replace its seal ? I should point out the build up has completely covered the fuel injector and electrical plug, it can no longer been seen.

Also my fuel economy is awful, around 17MPG ( urban ), is this a side effect of the leaking injector ?

Any advice greatfully received.

Jon

As the seal only costs a few pennies my logic would be to just replace the seal first, if you still have a leak after that then its likely to be from the actual injector.

Any fuel leak isnt going to help fuel economy and the reason yours is so poor could be because the injector is faulty or because of other reasons such as a blocked air filter, etc.

I get no less than 28mpg urban from my ML270.

 

[exeng]

replace screw and be careful

You should replace the injector screw at the same time and do not try to remove when engine is cold warm up engine caution when removing screw as they can snap when rebuilding make sure you clean out screw hole as well as injector hole.star do a grease to coat parts with to aid removal next time the screw and copper washer should cost under £2

 

[BlackC55]

The seat of the injector needs to be re-cut to avoid this happening again. I have the tool if you need it.

A diesel specialist can also do it for you.

I would avoid doing it yourself unless you are a competant mechanic with the right tools. I also have a special cleaning kit for them.

5/10 the injector is damaged when removing.

 

[JonWhitehouse]

Hi

Thanks for all the advice. I have replaced the injector tonight and all seems OK. I obtained a second hand injector for £65 just in case I damaged the old one when chipping the carbon off. To be honest it came off very easily and a vacume sucked up the chippings. It took a long time to clear around the connector and spill pipe. Once the old injecot was removed I cleaned the seat and the seat inside the head where the injector seals on the copper washer. I replaced this copper washer with a new part from MB and also used a new stretch bolt. I also purchased "special grease" from MB to grease the injector with before I inserted it. I used my replacement injector just in case the old one had a fault and all seems to be well. There was a chuffing noise from the injector before I did the wrok and now it seems to have gone.

The hardest part of the job was clearing out the bolt hole as I was worried the bolt would bottom out on carbon before it had pulled the injector up tight enough. I did this with the old stretch bolt with a saw cut up the threads and just kept putting it in and out removing the little bits at a time.

The injector that was at fault was the rear one ( hardest to reach ). The carbon had built up over a sensor in the head to the left of this injector. This sensor is the oil sensor. Another fault my vehicle had was from time to time the oil warning light would come on even though the oil level was fine. This fault seems to have gone now also. I think maybe the carbon was transfering heat from the head into this sensor body and causing it to read faulty. Now the carbon has been removed from it it seems to work fine.

Hopefully these faults are now cured. Thank you allfor your advice and help.I will keep my eye on it for the next few weeks to make sure it has sealed.

Jon

 

[Wellseyoffroad]

Hi can I ask do the injector removal kits you can buy on ebay work when the injector has been leaking and the black stuff has got round it. I have cleaned the black off and removed the stretch bolt, I have give it some careful waggle and twist with grips, but now left it to soak with thin spray oil, should i try a kit or is it more difficult, also where do you get the tool for cutting the seat again, regards phil

 

[Wellseyoffroad]

It's a little late but I loosend the fixing bolt to the injector, left it in place, and drove the car, that got it free, it was a risk but, and don't accept any liabilaty for dammage by trying this.