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Low Coolant Warning on 2020 E450 - Finding the Leak!

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David L. · rep 0 · May 25, 3:08 AM · 1 replies · solved · Question

Vehicle: 2020 Mercedes-Benz E450

Hello everyone,

I recently got a 'Check Coolant Level' warning on my 2020 Mercedes-Benz E450 (W213 chassis, M276 engine). I checked the reservoir, and it was indeed a bit low. I topped it off with the correct Zerex G40 coolant, but after a few days, the warning came back. I've also noticed a small, faint pinkish puddle under the front passenger side of the car a couple of times.

I'm trying to locate the source of this leak. Are there any common spots on these E-Class models that tend to leak coolant? I've heard about thermostat housings or water pumps on other models, but not sure about mine. Any tips for finding it without a pressure tester?

Thanks for the help!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:08 AM

0

ClearTheCode admin answer:

Experiencing a recurring low coolant warning and finding puddles is a clear sign of a leak that needs prompt attention to prevent potential engine damage from overheating. The pinkish color confirms it's likely your G40 coolant.

Common Coolant Leak Points on M276 Engines (like in your 2020 E450):

  1. Thermostat Housing/Water Pump Area: While less common for a 2020 model, the area around the water pump and thermostat housing on the front of the engine is a frequent leak point as seals age.
  2. Coolant Hoses and Connections: Inspect all visible coolant hoses, especially where they connect to the radiator, engine, and heater core lines. Look for swelling, cracks, or crusty residue around clamps.
  3. Radiator: Check the radiator fins and end tanks for any signs of leaks, especially at the bottom where the plastic end tanks meet the aluminum core.
  4. Expansion Tank: The coolant expansion tank itself can develop cracks, or its cap might not be sealing properly.
  5. Oil Cooler Seal (less common for coolant, but worth mentioning): Sometimes the oil cooler seals can fail, leading to internal mixing or external leaks, but this usually presents differently.

DIY Leak Detection Steps (without a pressure tester):

  1. Visual Inspection (Cold Engine): With the engine cold, carefully inspect the areas mentioned above. Use a flashlight to look into crevices. Pay close attention to the front passenger side, as that's where you've seen puddles.
  2. Visual Inspection (Warm Engine - CAUTION!): After a drive, park the car and immediately look for steam, drips, or wet spots. Be extremely cautious around a hot engine and pressurized cooling system. Do NOT open the coolant cap when hot.
  3. Cardboard Test: Place a large piece of clean cardboard under the front of your car overnight. The location of the drips on the cardboard can help pinpoint the general area of the leak.
  4. Smell Test: Sometimes, a sweet smell of coolant can indicate a leak, even if you can't see it.

When to See a Shop:

  • Difficulty Locating Leak: If you can't find the source of the leak after a thorough visual inspection.
  • Persistent Low Coolant: If you continue to lose coolant rapidly, indicating a significant leak.
  • Overheating: If your engine temperature gauge starts to climb into the red, pull over immediately and have the vehicle towed to a shop. Driving an overheating engine can cause severe, irreversible damage.
  • Internal Leaks: If you notice white smoke from the exhaust, coolant in your oil (milky oil), or oil in your coolant, this indicates a more serious internal engine leak (e.g., head gasket) requiring professional diagnosis and repair.
  • OBD Codes: While coolant leaks rarely trigger specific OBD codes unless they lead to overheating (e.g., P0117 - Engine Coolant Temperature Sensor 1 Circuit Low), persistent overheating will eventually trigger codes and potentially put the car into limp mode.
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