Mercedes-Benz Coolant Expansion Tank Hose Replacement Guide

In this guide, you will find instructions on replacing a Mercedes Benz GL450 small diameter coolant line that connects the engine, radiator, and expansion tank. 

Contents

A defective coolant overflow line may let the expanding coolant vent out of the coolant reservoir tank, decreasing the coolant level.

Symptoms

One of the common symptoms of a defective plastic coolant overflow line is that the coolant level is decreasing and the engine overheats. 

What you will need

Parts

Tools

Procedure

  1. Park on level ground.
  2. Shift the car in park, then turn off the engine.
  3. Let the engine cool down to avoid serious injuries.
  4. Open the hood.
  5. Find the coolant overflow line which stretches from the engine to the radiator and finally to the coolant reservoir.
  6. Use a flat-head screwdriver to pull each connector's retaining clip.pull-clips
  7. Prepare the new coolant overflow line.
  8. To connect the coolant overflow line to the radiator connector, align the line with the notch on the radiator side, then press down on the locking clip.install-radiator-side
  9. Align the coolant line to the connector on the reservoir side, then push it until it doesn't move anymore, then push down the locking clip to lock it in place. Note: to minimize the effort in pushing in the line, you may lubricate the connector seal with coolant.install-reservoir-side

     

Repeat the procedure for the engine side.

What does the overflow hose do?

  • An overflow hose connects to the radiator below the cap and the reservoir tank to store the overflow of coolant.
DIY Cost: $40-$180
Est. Time: 30-1 hr
Difficulty: Easy
Mercedes-Benz Coolant Expansion Tank Hose Replacement Guide A defective coolant overflow line may let the expanding coolant vent out of the coolant reservoir tank, decreasing the coolant level. Symptoms One of the common symptoms of a defective plastic coolant overflow line is that the coolant level is decreasing and the engine overheats.  What you will need Parts