High transmission warning + Low coolant light
 

Since the first CLS was introduced, it was the only Mercedes model that got my attention. But I prefer BMW so after using a few, it was time to change so I chose CLS 53 over M340i.

I took delivery of a brand new CLS 53 AMG on 14 Dec 2021. After leaving from the dealer, I drove 100km to my destination and got a high transmission temperature warning of 121 Celsius when I arrive. I drove in comfort mode and not over 120km/h. After that, I get a yellow low coolant light warning. After a few days, I took it to the dealer to check and fix. After 2 days, they changed one of the coolant pump and the car has passed testing and able to release to me. I drove it for 2 days with no problem. And then, the low coolant warning light came up again. And then, it was sent back to the dealer to check. I haven’t got reply on the status yet.

This is really unacceptable for a brand new car. My experience with the CLS 53 has been nothing but problems!

has anyone have the low coolant warning light experience with the CLS 53?

Although MBUSA released this Recall for 2019 model year suggest dealer check harness of interest.

Thank you very much for your reply. I will pass this to my dealer.
I called to check the progress today but the dealer said they have sent the vehicle information to Mercedes Thailand and now waiting for their feedback. Nothing has been fixed on my car but the low coolant warning is gone.

Usually Mercedes are much more reliable than BMW, even though we have had some high mileage BMWs in the family. Ironic yours is giving you issues, hope its easy fix. 53 is a great platform.

Most of BMW and Mercedes in Thailand are CKD models. My CLS 53 is CKD assembled in Thailand. I don’t know if this makes any difference in quality.

In general, what I’m experiencing should be an easy fix but talking the the dealer, it sounds like they have ran out of checks to perform and need to wait for Mercedes Thailand to diagnose and suggest a check or fix procedure. My worry is that this is not an easy fix and I’m just the lucky one who is experiencing this in a 53.

I haven’t driven this car like how a 53 should be driven yet.

Sorry about your issues. Never saw that light come on.
I have a 2019 CLS53.

Let the dealer get it fixed. I agree it's unacceptable. This vehicle is so advanced inside it's mind boggling.

Keep us posted.

The dealer called me last week and informed me that they found that the coolant bleed was not properly performed when they change the water pump which resulted in trapped air inside the coolant system. they suspect that the trapped air in the coolant gave the low coolant warning sign. So they burp the coolant to get rid of the trapped air. I picked up the car 3 days ago and everything is normal.

the temperature readings after a 30~60 min drive are
Engine: 100~105 Celsius
Transmission: 85 Celsius
Coolant: 90 Celsius

Rick2019: Thank you for your reply. If it's not too much trouble, please help me on my questions below.
1. According to your experience, are the temperature readings normal?
2. Can you please check this out (https://mbworld.org/forums/cls-coupe...-bubbling.html) and let me know your comments? is this really normal? My blood pressure goes crazy seeing the bubbling in the pink coolant reservoir. Thanks a lot~

Surprised they admitted their error.