GL320 CDI lots Fuel leaking on the ground from back of engine above the transmission

[Can mark]

lots of diesel fuel is leaking from a drain hole, seems the hole is for drain purpose, which is at/on top part of transmission. We noticed that it used to leaking/drain engine oil from there, after fix the engine oil issue, now it is leaking fuel from the hole, we can’t figure out why, it seems there is no connection between the drain hole and fuel, where is the fuel coming from?

Have checked all the fuel line and return line, there is no leaking, one fuel injector is a bit leaking from outside but it is not the cause of leaking drips lots of fuel, after turn the engine on, we can see from the bottom, it starts dripping.

except the fuel line, is there any other place can cause the fuel leaking like this? can cause the fuel leaking into the drain hole?

if fuel injector faulty, can it cause the fuel leak from inside the engine to outside into the drain, not go through the fuel return line? Is it possible?

need help, please

thanks!!!

Mark

 

[Jim2]

lots of diesel fuel is leaking from a drain hole, seems the hole is for drain purpose, which is at/on top part of transmission. We noticed that it used to leaking/drain engine oil from there, after fix the engine oil issue, now it is leaking fuel from the hole, we can’t figure out why, it seems there is no connection between the drain hole and fuel, where is the fuel coming from?

Have checked all the fuel line and return line, there is no leaking, one fuel injector is a bit leaking from outside but it is not the cause of leaking drips lots of fuel, after turn the engine on, we can see from the bottom, it starts dripping.

except the fuel line, is there any other place can cause the fuel leaking like this? can cause the fuel leaking into the drain hole?

if fuel injector faulty, can it cause the fuel leak from inside the engine to outside into the drain, not go through the fuel return line? Is it possible?

need help, please

thanks!!!

Mark

If the pipe is directly connected to the transmission, then it has nothing to do with the engine..but if it's from the engine, and only routed alongside the transmission, yes, that's from the engine, and you should be able to trace it back to where it is connected to the engine. Would help if you can confirm what kind of oil it is. Could be engine oil, fuel, or transmission fluid.

 

[Can mark]

thanks Jim.

It is fresh clean disel, I can smell it, for sure it is not engine oil, it is light colour.

I believe one mechanic said the hole is connected to engine’s V basin for drain purpose, I am not sure.
the car used to have engine oil leak from turbo, it is said also the engine oil leak/drain from there.

but where can the leaking fresh diesel be possibly comming from, if not from fuel lines and oil filter, not from the engine top.

if the leaking is from engine, can it be that much, dripping while driving

 

[andrew056]

I take it the engine is an OM 642 so the fuel filter is in the V so that would be the first place to look . You'll have to remove the intake from the turbo to get at
the fuel filter .

 

[mioba]

is the car running OK, a fuel leak of the proportion "lots" would presumably cause running issues.
I assumption based on the location would be a fuel line from tank to filter.

A non seated injector would give running issues, but probably not a leak of your magnitude.

Not sure how handy you are to DIY, or if you are looking for pointers for a garage, you need to get the engine covers off, batwing and start following the fuel circuit from the top, likewise get undertrays off, car on stands and follow the circuit from the bottom. Its the only way.

 

[Can mark]

Thanks Andrew
we did take out the fuel filter out from the middle of engine, top and bottom of fuel filter all dry and clean, but there is no sign of fuel leaking, very strange

 

[Can mark]

thanks mioba
car is still running ok, it just a bit hard to start, need several cranking.
lots fuel leaking I mean after car started, I can see underneath at back of engine, the fuel is dripping.

So far we only checked the fuel lines on the top part of the engine, also from fuel tank to the the place we can see, but no leaking sign.

the fuel leaking from the drain hole is the puzzle, we don’t see any connection between them.

You give a good suggestion, we will try to trace the fuel
line again, since there is still some part of fuel line is covered by the car body or engine, we can’t see through or access it, we will try to find out whether it is leaking from the hidden part Of fuel line.

 

[mioba]

could it be the fuel pump - just a thought, leaking out back

 

[Can mark]

could it be the fuel pump - just a thought, leaking out back

Thanks mioba,
om642 engine HP fuel pump is at front of engine, the area looks dry and clean, no sign of leaking

 

[mersum1es]

cracked injector nozzle holder.

 

[Can mark]

cracked injector nozzle holder.

thanks mersum1es

if it is the case, the leaking diesel should be inside engine? then we should not see fresh diesel leaking/dripping from outside，is it correct?
but we see clean fuel leaking underneath

 

[Doug1234]

Plastic junction block where the injector return lines join up, behind thermostat / left of fuel filter. If it leaks from one of these it could do so underneath unseen.

 

[Can mark]

Plastic junction block where the injector return lines join up, behind thermostat / left of fuel filter. If it leaks from one of these it could do so underneath unseen.

Thanks Doug.
we will recheck the fuel lines

 

[mersum1es]

thanks mersum1es

if it is the case, the leaking diesel should be inside engine? then we should not see fresh diesel leaking/dripping from outside，is it correct?
but we see clean fuel leaking underneath

Nope, diesel pours on injector foot.

 

[Can mark]

Thanks everyone!
I think our issue is located, on top of engine cover beside where the #3 injector seat, there is a drain hole, when injector or return line is leaking, the fuel will be drained down through the hole, so now we can see/understand the connection between the fresh fuel and the drain hole.

since the leaking fuel is drained quickly, we cannot see much leaking fuel from top of the engine.

thanks everyone for the help!

 

[Craiglxviii]

I had this problem with our R320. Knackered injector seal was squirting fresh clean diesel into the inside of the V. Only with ours it ran out of the front and washed the perpetually dirty engine clean, leaving lots of thinned-out oil spots on the drive.

Check for injector leskoff.