Chasvs

I just bought a 2012 CPO ML350 Bluetec. I love it but it has a distinct diesel odor in the cabin. There is no smell from the exterior of the vehicle, and nothing leaking under engine on the ground. But when I get into the vehicle, I smell diesel. Is this characteristic of these diesels or not? This sort of fuel odor isn't something you'd ever experience with a gas engine unless there was some sort of leak of fuel or something.

Can anyone chime in on this from their experiences with the Bluetecs?

MBduck

There is no diesel smell at all inside or outside our ML BlueTec.

Shadow5501

I have seen the short exhaust flex pipe which bolts to the back of the turbocharger crack and leak exhaust on the OM642 engine. It caused diesel exhaust smell when the car was stopped, though it was OK while moving.

You can remove the big plastic engine cover - it just lifts off - and inspect for signs of black soot where the exhaust exits the turbocharger at the back of the "V" of the engine.

You could also have a small diesel fuel leak. Warm fuel and untreated exhaust smell a lot alike. The fuel filter can leak, the O-rings on the water sensor don't last forever.

Shrdlu

You shouldn't be smelling diesel fumes inside or outside. One possibility: someone spilled diesel fuel on the carpet. The stuff takes forever to evaporate and the odor lingers.

Chasvs

Thanks,

It's got to go in soon for some stuff anyway so I'll mention that to them and have them check it out. I figured this wasn't normal and you've confirmed that for me.

Shadow5501

Shrdlu makes a good point. It could be as simple as someone got diesel on their shoes while filling the ML, then tracked it into the cabin. For some reason the diesel pumps frequently seem to have a mess on the ground.

Does the cabin always smell of diesel, or only after you start the engine/drive the car a bit?

Chasvs

I only notice it when I get in after it's sat for some time. While driving I don't smell it any longer probably because the A/C is running all the time here in Florida.

Shadow5501

OK, that sounds more like you have diesel on the floor mats than any type of mechanical problem under the hood. Most likely it's the drivers floor mat. You can just take it out of the car and see if the problem goes away. If so, replace it or give it a good cleaning.

I suppose you could give the mat the sniff test, just don't make sure nobody sees you doing it.

Chasvs

The car is new (used) CPO from a MB dealer. Believe it would have been thoroughly cleaned so I doubt it's that simple. It's in the dealers shop now for this and some options I paid for so we'll see what they have to say.

Chasvs

Well the ML is back from the shop and they didn't find any signs of a fuel leak. They checked the engine bay and the the fuel filler pipe area and found nothing. They did a de-ionization treatment along with the interior protector treatment and it's smelling pretty good right now. The Protector had a rather strong smell but that's pretty much gone this morning. There's no fuel smell on the floor mat so that's all good, but I've ordered a new set of mats to make sure it stays fresh.

vancitydsb

I have the same issue and looked under the hood, i do have black soot near the back of the motor just below the windshield. How can I fix this? the odor is so strong and annoying.

david

tdennehy

I have the same problem. It smells like diesel fuel sometimes. Not always, though. No fuel on the carpets, since I took them out and smell exists. I want to say I don't smell it in the morning when it is cold. I could be wrong. I am wondering what's going on with it. It has a bunch of AEM recalls that need to be done on it, but MB is dragging their feet on doing the work.

tdennehy

I found same thing. I took the black plastic motor cover thingy off. I see an area where oily residue is getting spayed out just a little bit.... Not sure what else to do.. I tightened a hose clamp, didn't seem to make a difference. Saw a "hose" that fits into a metal part, pressure fit, I am assuming as there is nothing holding it in. Might be that too.