Petrol in a Diesel Mercedes CLC? Leave It Switched Off
When you've got petrol in a diesel Mercedes CLC but your motor hasn't been started, leave it turned off, even to shift it away from the petrol pump. That petrol cannot get out of the tank whilst your engine is off, so your CLC can usually be set right with a drain.
Your Mercedes CLC can be left wherever it ended up, forecourt or not, because Petrol in Diesel drains misfuelled cars on the spot. Hold off attempting anything on your own until you have rung us, and we'll tell you what to do.
Put petrol in a diesel CLC? First steps
- With petrol inside the tank, a diesel CLC will usually still start and run, and feel perfectly normal for some miles. That's how motorists frequently drive off without noticing a fault, and why your motor should be left off.
- Your ignition needs to remain off as well, because turning it on starts the fuel pump priming on plenty of diesels, and your pump then pulls fuel out of your tank.
- Do not fill the rest of your tank with diesel to thin it. Your CLC takes up to 62 litres, and filling it up just means more tainted fuel to drain. Super unleaded is petrol here too.
- Speak to the forecourt attendants if your car is in the way of a pump. They usually help roll the vehicle clear after it's in neutral.
- Ring 0333 366 0103 with the place the CLC is and which one it is, the approximate quantity of petrol that went in, and whether it has been run. If you can see the precise variant on the badging, for instance the CLC 200 CDI, that helps as well.
Driving on wrong fuel in your Mercedes CLC
Wrong fuel in your Mercedes CLC only starts to get to the engine after it's pulled from the tank, which is what starting the motor does. As it flows through, diesel fuel leaves the high-pressure fuel pump and the fuel injectors lubricated, and your engine depends on that. Petrol thins your diesel and takes that protection away, which is why it is driving any distance on the mixture that can do harm.
Where you've already driven the CLC, stop in a safe place then switch off. All the same, we can take all the contaminated fuel out, by draining the tank and then rinsing the fuel pipes and the filter. Provided it's flushed out thoroughly after being caught early, it very rarely leaves permanent harm.
It's the same whatever variant of the CLC you drive, including the CLC 220 CDI.
Mercedes CLC fuel tank capacity
Because the risk depends on what proportion of your fuel is petrol, the size of your tank counts, and a couple of litres in a tank that was almost empty are more of a problem than the same in a fuller tank.
Each diesel Mercedes CLC we hold figures for uses the same tank, which holds 62 litres, so the variant you drive does not change that calculation.
| Version | Fuel tank |
|---|---|
| Mercedes CLC 200 CDI | 62 litres |
| Mercedes CLC 220 CDI | 62 litres |
Checking your diesel CLC version
The variant is normally on the badging on your boot lid, and it's useful for us to know when you call.
Look for CDI on the badge of a diesel CLC.
AdBlue in a diesel Mercedes CLC
Water and urea go into AdBlue, which some diesel vehicles use to treat their exhaust. It is stored in a tank of its own, with its own filler. Even to shift the vehicle, don't touch the key when you've got AdBlue in a diesel Mercedes CLC after it went into the incorrect filler.
The fuel pump gets no lubrication at all from AdBlue, which is mostly water and won't ignite. It won't blend with diesel either, and drops to the bottom of the tank, the same location the pump draws from, so a tank of up to 62 litres won't dilute it.
A modest amount is still pulled into the fuel system. When the water has evaporated, what is left is urea, which crystallises inside your fuel system, filter and injectors included, and attacks any metalwork it sits against.
Where the CLC has an AdBlue filler, it might well lie next to your diesel filler under the same flap, as it does on a lot of vehicles. You can typically tell the AdBlue lid by its blue shade and the much narrower nozzle it fits.
How a fuel drain on your Mercedes CLC works
A fuel drain on your Mercedes CLC is carried out at the car, and it never needs to be taken to a garage. Before we start the engine, the fuel system is primed and your tank refilled with fresh diesel. First comes checking what went in and whether it's run, draining a tank that holds up to 62 litres on the CLC, and rinsing the lines and filter.
Once we've finished, your CLC is running on fresh diesel and you can drive off in it.
AdBlue removal from a diesel Mercedes CLC
Just like emptying petrol, AdBlue removal from a diesel Mercedes CLC runs through the same stages. If the CLC has been run, AdBlue can leave crystals in the lines, since it settles under your diesel instead of blending in. We rinse those through as well, and change your fuel filter where needed.
AdBlue removal, as we use the term here, is about AdBlue that went in the incorrect filler and has to come out of the diesel tank. It does not cover taking out or disabling the AdBlue system on the car.
What decides the price of a fuel drain on the Mercedes CLC
The work varies from one job to the next, so we don't publish a set price. The chief things that shape it are these:
- whether the CLC has been started or driven, which makes the biggest difference
- how much went in relative to the size of the tank
- what was put in, petrol or AdBlue
- where you are with the CLC, and whether it's safe to bring the van there
Ring with those answers and we'll be able to explain what's likely to be involved.
Questions about petrol in a diesel Mercedes CLC
How many litres is the Mercedes CLC fuel tank capacity?
It takes 62 litres, and our data show the same tank on every version.
Can I fill up with diesel if I only put a little petrol in my CLC?
Topping up just lowers the proportion of petrol. None of it is removed, so it is all still there when you drive off, which is why we wouldn't recommend it. With just a little petrol, a drain to get all of it out is usually all the CLC requires.
Do I have to take my CLC to the Mercedes dealer?
No. We are independent with no connection with Mercedes or its dealers, plus we empty and clean the CLC wherever it is, so there's no need to move it anywhere.
Does it help to know which CLC I have?
Yes, it helps. Our data include 2 diesel variants of the CLC, so let us know which one you drive when you call.
Will my insurance pay for wrong fuel in my Mercedes CLC?
It's worth checking your insurance, as misfuelling cover is included in some and not others. Whatever it says, we come out to drain your vehicle.
What should I do if my CLC got diesel in its AdBlue tank?
In this case, too, the sensible thing is to leave the ignition alone. When it is driven like that, a vehicle will normally show an alert and go into limp mode. The AdBlue system needs draining as well. When you call, tell us which tank your diesel was put in.
I have already driven my CLC. What do I do?
Stop where it is safe and turn the engine off, then leave it off until we arrive. Catching it this soon means long-term harm is very unusual, and we empty and clean the fuel system wherever you are.