Fuel Leaking? Engine Over Heating? Something else?

[cbsml270]

I am currently trying to find out what could be causing my ML 270's engine to emit steam when idle in traffic etc.

I have a fuel leak..and a little oil leak I have been advised. I have had 3 garages look into this. 2 have said injector 1 is goosed (bodge job) and the 3rd - the garage I purchased from said they replaced said injector and the bodge work was bad prior to them getting it. (Dont worry I know that's naughty of them to sell a car like this and I will use this to my advantage)

The car runs well? 400+ miles to a tank and I only notice the steam when stopped. Couple of pointers.....now I have replaced the thermostat, and the right side coolant temp switch.I took it back to the garage I purchased from (140 mile round trip!) for them to check out the fuel leak . They sprayed the injectors and none where showing signs of leaking when running idle and I can't recall the steam showing as bonnet was up.

Its smells like fuel said qualified mechanic????? But it is getting worse. Engine is not overheating, in fact sits at a perfect 87 ish.

Could it be a fuel leaking elsewhere. Could all of the tar on the injectors, the back of the engine cover (long mercedes one) that when heating up emit steam vapours or coolant leak as a cause. I did top up using a normal 50/50 coolant do I need a special one?

Thanks in advance.

 

[michael8554]

I would monitor the coolant level, if it's leaking coolant the level will go down.
But you say you have already had to add coolant, was that because the level was incorrect?
Then it must be leaking.
Also, why not lift the bonnet when it's warm and look for the source of the steam?
If you find its not leaking after all, perhaps the leaking fuel from your injector is evaporating on the hot engine and looks like steam?
(I've never seen evaporating diesel so just guessing)

 

[cbsml270]

Thanks for the advise. I topped or shall we say replaced around 5l of coolant after the thermostat was replaced. It is level and doesn't appear to be going down.

I have popped the bonnet whilst engine running and the steam goes....what I have seen is back of the engine towards battery way. I did notice whilst sitting in traffic that the steam was coming out of the front grille, normally it's just from under the bonnet where the battery is. Battery is fine no issues or bad smells etc.

 

[michael8554]

If the level isn't going down the leak must be very subtle (and will be hard to find) but I would re-tighten any hose clips involved in the thermostat change.

 

[jay1983]

400+ miles from a tank with suspected fuel leak??!!

Not bad for an ml

 

[cbsml270]

400+ miles from a tank with suspected fuel leak??!!

Not bad for an ml

Agree. 250miles for 50 quid or so is what I average a week.

I'm lost....however I am going to clean the black death aftermath at the weekend and will check all the hoses.

Relating back to my issue. It's only when the engine is warm will it amit the steam from what I can see

 

[ducatiboy]

Check top of engine and look for this small item . Have engine running u will see small drops of fuel if its leaking only bout 10 pound to replace



Small white item

 

[cbsml270]

You absolute beauty ducatiboy. I wondered why that part didn't look right it's missing the white part. I will get the part straight away and up date in due course.

 

[xp2500]

Out of interest ... what is the small white item/ what does it do?

 

[cbsml270]

Out of interest ... what is the small white item/ what does it do?

That's my issue. Done a Google search and nothing. Been to Eurocar parts and they didn't even know. Said try a dealer

 

[cbsml270]

Update....its injector 4 puffing! Oh well the garage I got it from can fix that. I was looking for the part number for the unit that has "the small white bit" and its pa6 6 gf35 which is a cap for the alternator pulley. I dont think that part needs replacing just the white end

 

[grober]

It may be for bleeding the fuel system- that's my guess. FUEL FILTER,LINES AND THERMOSTAT INJECTION PUMP íà Mercedes OM 612 DE LA (612.963) | Êàòàëîã çàï÷àñòåé Mercedes, ïîäáîð àâòîçàï÷àñòåé äëÿ ëåãêîâûõ àâòîìîáèëåé Ìåðñåäåñ (ðåãèîí Åâðîïà) ïî àâòîêàòàëîãó.