Why a Benz tells you when it's due
Mercedes-Benz brought in its ASSYST service computer back in the W210 E-Class era, and Wikipedia says it introduced flexible service intervals based on operating conditions. So on cars that use it, two Benzes of the same age can be due at quite different times.
That's why the display matters more than the date of the last service. When the message comes up, note what it says and the kilometres, and pass both on with the job.
After the service, the mechanic resets the display with diagnostic equipment. A garage that sees Benzes often will have it; ask before you book a time.
When the AdBlue warning comes on
Read the message
AA New Zealand says the car gives a series of alerts before the diesel exhaust fluid tank (AdBlue is one brand name) runs dry. Note what it says and plan a fill-up that day.
Fill the right tank
It has its own filler, separate from the diesel. AA New Zealand warns that some truck stops sell it from the same pumps as fuel, so read the pump label before you fill.
Wrong tank? Leave the key alone
If it's gone into the fuel tank, don't start the engine or even switch the ignition on. Have the car moved to a mechanic without starting it, and tell them exactly what went in.
If it's run out
Wikipedia notes a BlueTEC diesel may drop into limp-home mode when the tank is empty, and AA New Zealand says it won't restart. Refill it, and if the warning stays on after filling, have the system checked.
Imported Benzes and the warranty
Not every Mercedes here was sold new here. Wikipedia notes most used imports come from Japan, and that most of the non-Japanese makes among them are German, with Mercedes-Benz named. An import may arrive without its service history and with a handbook in Japanese.
Motoring NZ reports that Mercedes-Benz set the precedent in New Zealand with a five-year, unlimited-kilometre warranty. If your car came in second-hand from overseas, ask Mercedes-Benz New Zealand with the VIN what cover, if any, it has before relying on it.
For a car under warranty, the MTA says a qualified independent mechanic should be low risk when the servicing follows Mercedes-Benz's guidelines. Whoever does the work, the Consumer Guarantees Act says it must be done with reasonable care and skill.
Signs a Benz should see a mechanic soon
- A service message that's already overdue.
- An AdBlue or emissions warning that stays on after the tank is filled.
- A yellow engine light, or the car feeling down on power.
- Gear changes that are suddenly harsh, slow or slipping.
- A red warning light of any kind: pull over somewhere safe and switch off.
What you can do yourself
You can
- Top up AdBlue from a sealed container, into its own filler only.
- Photograph the service display and any warning message.
- Keep every service invoice with the car's papers.
Leave to the mechanic
- The service the display calls for, and resetting it.
- Any fault in the AdBlue or exhaust system.
- Gearbox, suspension and electrical diagnosis.
If it were our Benz
We'd take a photo of the service display, find out whether the car was sold new here, and check whether any Mercedes-Benz warranty still applies. Then we'd hand it to a mechanic who works on Mercedes-Benz every week, with the diagnostic equipment to reset the display, and ask for the service items and oil named in the quote.