Water in diesel fuel line
 

On the effective 3rd day, after driving 20 miles, the "check fuel filter" message came on. I drove the ML to the dealer, and after the Tech looked at the problem, they said it may be a a faulty sensor.

I checked the manual, and page 257 says:
"!

X Visit a qualified specialist workshop."

I emailed this to the Service Advisor.

Later in the day, they came back to me and confirmed there was indeed water in the fuel line.

To cut a long story short, the ML is still in the workshop after 4 days. They drained the tank, filled it up again and drove around a fair bit , but the engine still exhibits hesitation.

So I am still in the loaner, where I have clocked up nearly 150 miles vs. 30 miles (out of 51 on the odometer) in my new ML.

Has anyone had this problem, and is this a hard problem to rectify?

Thanks much.

Sound like a bad batch of diesel. Draining the tank should have fixed the problem--unless they refilled from the same place where they got the contaminated fuel in the first place.

If you bought new and have only driven 51 miles, that means you are still on the fuel the dealer put in when they delivered with a full tank. As SHRDLU said, make sure they did not refuel from the same local fuel station, and probably more of their BlueTEC's on the lot are going to have similar issues.

Could they really be that stupid? Oh wait. . . never mind.

28 out of 51 miles
 

Actually, I only drove 28 out of the 51 miles on a brand new ML Bluetec.:) But I did put 150 miles on the loaner!

And yes, the fuel gauge barely budged, so still on the dealer's first tank.

I hope they have the presence of mind NOT to fill up again at the same gas station, but, who knows? :crazy:

I got the name of the gas station from them, and will make sure I NEVER go there.

Hope I get my ML back on Monday, haven't even had time to unpack the set of all-weather mats I bought.

I guess we don't know exactly what happened with your ML, but it reminds me that when it comes to fueling diesels, you probably want to buy at a station that sells the most diesel fuel. You don't want to buy from a station that sells a tank or two a day. Fuel that sits for a long time in the storage tanks is more likely to have water in it. There are also maintenance guidelines that stations are supposed to follow to ensure clean, dry fuel, and it's important that those are followed, but I don't know how a customer knows if they do. I'm sure if you ask them, they'll all say they do.

Fortunately, stations that sell a lot of diesel usually do so because they have good pricing.

picking the right diesel gas station
 

Thanks, will keep this in mind when I go to fill up my first tank (that I buy). In this case, this is fuel that came with the new ML at delivery....

I took the ML to Wendy's tonight and found that as I drive down the street under light acceleration there was a little hesitation. The engine was already driven today and it was 65 degrees out. The problem went away after a few minutes but now I'm really looking hard to see if it does it again.

Diesel fuel
 

Service Mgr and Sales Rep told me that I need to find a gas station that sells a lot of diesel. Because diesel is not as popular as gas here in the US, that makes sense. They also said to ask the station when was the last delivery, and if it is not a few days ago, then I may want to move on.

Got the ML back today, but only drove less than 2 miles home, so will know in a couple of days.

Water in diesel fuel line - final outcome
 

Here is the final (hopefully!) outcome of the water in fuel problem:

1. Dealer would not unequivocallyy state it was water from the gas station when the first tank was filled, or whether there was already water in the system at delivery to the dealer. Diagnostic code was 162500 in CDI motor control unit.
2. They replaced fuel filter, hose clamp, loom tie,sealing cap and o-ring.

Dealer and service advisor were responsive great to work with, and to compensate for my inconvenience with the ML spending a total of 5 days in the workshop, they tinted the front windows and detailed the car (they clocked up over 50 miles on the ML during diagnosis and repairs).

Other relevant data: Just before I noticed the "Check Fuel Filter" message, the engine (warm) was sputtering, but I thought it was jerky transmission shifts.

Hopefully, finally I get to enjoy the new purchase!

Issues with ML350 2012
 

Any other issues after 4 years driving your ML?