How to Check and Top Up the Coolant Level on a Mercedes

How to Check and Top Up the Coolant Level on a Mercedes

If you see the “Check coolant level” or “Top up coolant” messages on your Mercedes, your coolant level is too low.

Ignoring these messages is like ignoring a thirsty plant – not a good idea if you want to keep things running smoothly.

This guide will walk you through checking and topping up your coolant in a Mercedes.

It’s easier than you might think; let’s dive in!

What do the “Check coolant level” or “Top Up Coolant” messages mean?

If the coolant level gets too low on a Mercedes, it will display one of the following error messages:

  • Check Coolant Level See Operator’s Manual
  • Top Up Coolant See Owner’s Manual

These messages are equal in their meaning; both indicate that your coolant level is too low.

You can see the “Check coolant level” or “Top up coolant” messages on various Mercedes models, including the C300, E350, GLE 350, ML350, and GL450.

As written in the Mercedes Owner’s manual, you should check your coolant level and add coolant if necessary:

Mercedes Check coolant level - owner's manual

Don’t panic, though; these messages are more of a gentle nudge rather than an emergency alert.

But it’s a nudge you should not ignore.

Without enough coolant, your engine can run too hot, and, just like us after a long day in the sun without water, it can start having problems.

Low coolant levels can lead to serious engine damage, and trust me, you don’t want to go down that road.

It’s way easier (and cheaper) to top up your coolant than to replace parts of your engine.

How do you check the coolant level on a Mercedes?

Great, you’re ready to check the coolant level in your Mercedes.

Don’t worry; you just need a bit of know-how and some caution.

Here’s a step-by-step guide:

  1. Ensure your engine is cool. Checking the coolant on a hot engine is a big no-no – it’s risky because the system is pressurized.
  2. Locate the coolant reservoir. You can find the coolant reservoir on a Mercedes under the hood on the passenger side. It is a half-translucent container that is labeled with a coolant icon:
Mercedes coolant reservoir location
  1. Check the coolant level. The reservoir will have markers indicating ‘Min’ (minimum) and ‘Max’ (maximum) levels. Without opening the cap, take a look at where the coolant level is. It should be between the Min and Max marks. If the level is below the Min mark, it’s time to add coolant. We’ll cover that in the next section.
  2. Check the coolant color. Also, take a quick look at the color of the coolant. It should be bright and clear. If it’s murky or has particles floating in it, it might be time for a coolant change – but that’s a different story.

If the coolant level is fine, but you’re still getting messages, it might be a sensor issue or a leak. In this case, a visit to the mechanic is a smart move.

How do you top up the coolant on a Mercedes?

So, you’ve discovered that your Mercedes needs some more coolant.

No worries, topping up the coolant is straightforward.

Here is the step-by-step process of topping up the coolant on your Mercedes:

  1. Get the right type of coolant. If your Mercedes is from April 2014 or earlier, it needs blue MB 326.0 coolant. If your Mercedes is from May 2014 or later, it needs pink MB 325.6 coolant.
  2. Mix the coolant if needed. If your coolant is not pre-mixed, you’ll need to mix it with water. Usually, it’s a 50/50 mix of coolant and distilled water.
  3. Open the coolant reservoir cap. Slowly open the coolant reservoir. Remember, even a cool engine can have some pressure build-up.
  4. Add the coolant. Using a funnel, pour the coolant into the reservoir up to the ‘Max’ mark. Be careful not to overfill.
Adding coolant to a Mercedes
  1. Close the coolant reservoir cap. Securely close the reservoir cap.
  2. Start your engine. Start your engine and let it run for a few minutes. This helps circulate the new coolant.
  3. Recheck the coolant level. Turn off the engine and wait for it to cool, then check the coolant level again. If it’s dropped significantly, you might have a leak and should consult a mechanic.

That was quite straightforward, right?

Remember, if you ever feel unsure, there’s no harm in taking your car to a professional.


If you have any more questions about your Mercedes’ coolant, here are the answers to some FAQs:

Can I top up Mercedes coolant with water?

It’s not recommended to top up your Mercedes’ coolant system with just water. While a small top-up with distilled water in an emergency is acceptable, it’s crucial to use the right type of coolant as soon as possible. Water alone can’t provide the necessary anti-freeze, anti-boil, and anti-corrosive properties, and it may also affect the cooling system’s efficiency.

What coolant do I put in my Mercedes?

If your Mercedes is from April 2014 or earlier, you should add blue MB 326.0 coolant. If your Mercedes is from May 2014 or later, you should add pink MB 325.6 coolant.

Is it Okay to just top up the coolant?

Yes, it’s okay to top up the coolant if the level is low. You don’t need to drain and refill your coolant completely if it’s still in good condition.

Can you drive with low coolant?

Driving with low coolant is possible for short distances but not advisable. Low coolant levels can lead to overheating, which can cause significant engine damage. If you notice your coolant is low, it’s best to top it up, especially for longer distances.


And there you have it!

You’re now well-equipped to keep your Mercedes’ coolant in check.

It’s great that you’re paying attention to the “Check coolant level” and “Top Up Coolant” dashboard messages.

And remember, always ensure your engine is cool before you start checking or topping up the coolant.

I hope this guide has been helpful in checking and topping up your Mercedes’ coolant.

If you have any more questions, don’t hesitate to reach out or check out more of our maintenance guides.

Happy driving!

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *