I own a 1999 E300 Turbodiesel. I checked under the engine, and I don't see any puddles, but there's definitely the faint smell of unburned diesel in the air, after you shut it off. Is this normal? The fuel economy seems to be OK - I get 32 MPG on the highway, and something less than that in stop and go traffic.

Anyone have any suggestions as to what might be the cause, and what hints to give the service department people?

 

Open the hood and look around the fuel injection pump, fuel injectors, fuel filters, for any wetness.

You could have a cracked fuel injection line as this is a common problem for diesels although you would have a drop in power if this is the case.

No, it is not normal to smell raw diesel fuel at any time!

 

how about the return line little hoses?check that too......

 

the vapor from the tank will have to pass the carbon canister before being disposed to the open air.

if this canister is broken, you will smell the strong odor of diesel. check the vent valve too.

 

I only smell diesel when the engine is running. I also can see some drops of diesel fuel on the ground after I park it. It isn't much diesel that's leaking, only a little bit, but it is definitely leaking diesel. I've got a 10am appt at the nearest dealer to have them look at it.

 

Unfortunately, I don't know what those would look like

I can see some small drops of diesel fuel on the ground when I park it. Power seems to be OK, but fuel economy in stop and go traffic is terrible - I averaged 17 MPG, which I know is way too low.

 

the leak must be coming from the return line right on top of the injectors. best way is to lift the car up and see.

look at the fuel filter too and lines.

 

They said they had to replace some fuel line hoses - I pick it up today, and give them this go-kart loaner I've been driving back

 

I've had the return lines replaced on my 95 300 D recently, and that took care of the diesel smell. Over time, the corrosiveness of the diesel fuel damages the gaskets, and return lines. The parts are not expensive, though the labor may run higher...