Already Driven With Petrol in a Diesel Mercedes S-Class?
The motor wants switching off then keeping off once you can pull over safely, if you've travelled on petrol in a diesel Mercedes S-Class. It is very uncommon for lasting harm to result if it's spotted early, and it can still be put right where you've stopped.
Your Mercedes S-Class can stay where it has ended up, because Petrol in Diesel travels out to it, empties its fuel tank there and clears its fuel system of petrol. We leave once it is running on clean diesel.
Petrol in a diesel S-Class: the symptoms to watch for
You may go a few miles without noticing anything wrong, because petrol in the fuel tank frequently leaves a diesel S-Class running as usual to begin with. People normally notice these signs if there's petrol or AdBlue in the fuel tank:
- power drops away, particularly as you ask the motor to accelerate
- the idle turns uneven, or it runs roughly
- there's more smoke than usual from the tailpipe
- a warning light lights up
- the motor cuts out and might not restart
Look at your receipt if one of these started after you filled up, because it shows which fuel went in.
What driving does with wrong fuel in your Mercedes S-Class
Till the motor draws it out, wrong fuel in your Mercedes S-Class remains in your tank, and driving draws it on to the fuel filter, and then into the injection pump and the fuel injectors. Diesel protects your pump and your fuel injectors as it flows through them and petrol weakens it, and so the farther the S-Class is taken, the more of your fuel system that blend gets to.
That's why it's wiser to stop as soon as you can than to finish the journey. Driving a long way on contaminated fuel is what can do harm, and when a vehicle is stopped early, draining and cleaning are usually all it requires.
Another version of the S-Class is no different from the S 350 Bluetec in this, and so which one is yours makes no difference.
We come to wherever you've stopped
The S-Class doesn't need moving anywhere. We come to it at the side of the road or outside your house, and so there is no reason to start it or arrange a tow.
On a main road, turn on the hazard lights, then choose somewhere safe to wait clear of the traffic.
Before you call 0333 366 0103, have your location to hand, along with the mileage you drove and which S-Class it is. If the badge gives the version, like the S 320 CDI 4-MATIC lang, that helps too.
Fuel drain on your Mercedes S-Class after it has been driven
Next to a drain on the forecourt, a fuel drain on your Mercedes S-Class goes a step further after a drive. After your tank is drained, your lines are opened and rinsed through along with your fuel filter, which leaves no petrol anywhere from your tank to the engine. Clean diesel goes in, your system is primed, and we fire up the engine to make sure it runs properly.
Emptying your tank comes first, and on the S 320 CDI it holds 88 litres.
Once it has run: AdBlue in a diesel Mercedes S-Class
Uneven running, smoke and warning lights are the usual symptoms once you've driven on AdBlue in a diesel Mercedes S-Class, and your car might then stall. AdBlue doesn't burn or lubricate, and it drops to the base of the tank where your pump draws fuel, and so it reaches your fuel line quickly. The urea crystallises in the filter and the lines once its water evaporates.
How AdBlue removal from a diesel Mercedes S-Class is done
AdBlue removal from a diesel Mercedes S-Class that has been run means emptying the fuel tank then clearing the crystals from the fuel lines and your filter, and we'll change the filter if it needs it.
Nothing here involves turning off or removing the AdBlue system. It deals with fluid in the diesel tank, and any separate AdBlue tank your S-Class has is left as it is.
The Mercedes S-Class fuel tank capacity and its engines
Diesel fuel tanks on the Mercedes S-Class range from 83 to 100 litres over the versions, with the S 300 Turbodiesel at the top and the S 250 CDI lang at the bottom end.
For instance, the S 350 CDI blueefficiency takes 90 litres.
Diesel S-Class versions wear CDI and BlueTEC badges.
One of those badged BlueTEC rather than CDI is the S 350 Bluetec lang.
| Version | Fuel tank |
|---|---|
| Mercedes S 250 CDI | 83 litres |
| Mercedes S 250 CDI lang | 83 litres |
| Mercedes S 300 Turbodiesel | 100 litres |
| Mercedes S 320 CDI | 88 litres |
| Mercedes S 320 CDI 4-MATIC lang | 90 litres |
| Mercedes S 320 CDI lang | 88 litres |
| Mercedes S 350 Bluetec | 90 litres |
| Mercedes S 350 Bluetec 4-MATIC | 90 litres |
| Mercedes S 350 Bluetec lang | 90 litres |
| Mercedes S 350 CDI blueefficiency | 90 litres |
| Mercedes S 350 Turbodiesel | 100 litres |
| Mercedes S 400 CDI | 88 litres |
| Mercedes S 400 CDI lang | 88 litres |
| Mercedes S 420 CDI | 90 litres |
| Mercedes S 420 CDI lang | 90 litres |
The price of a fuel drain on the Mercedes S-Class after driving
How far it travelled and where it has stopped are what mostly decide the price of a fuel drain on the Mercedes S-Class after a drive, and petrol or AdBlue makes a difference too. Those details are what we need when you phone, and with them we can explain what the job will need.
Usual queries about petrol in a diesel Mercedes S-Class after a drive
Is my S-Class ruined?
The likelihood of that is very low. We empty and clean the system wherever you have pulled up, and when your car has been stopped soon, permanent damage is rare.
Should I drive it home first?
We would ask you not to. Tainted fuel reaches further into your system with every mile, which means you can keep the S-Class where it is while we drain it there, with no need to move it.
Stalled, and it won't restart: what should I do next?
Trying again draws more of the mixture through on every attempt. Please leave it alone. With it emptied and flushed and fresh diesel in, we prime the fuel system and get it started for you.
Do you need to know which S-Class I own?
There are 15 diesel versions of the S-Class, and the badge on the boot shows which one you have. Knowing that helps us when you call.
Does my policy cover wrong fuel in my Mercedes S-Class?
Misfuelling cover is offered in some insurance policies, so check yours after the vehicle has been sorted out. Whatever it says, we still come out.