Tune Up Your Tesla Model S: Overhauling the Cooling System

There are roughly 250,000 Tesla Model S sedans on the roads around the world with more than half of them in the United States. Production of the Model S started in 2012, which gave a decade plus for DIYers and other curious service repair technicians to tinker. It turns out that the Tesla Model S isn’t as mysterious under the hood as many would think. Let’s take a look at what it takes to do an overhaul of its cooling system.

Why Does an EV Need a Cooling System?

The Tesla Model S thermal management system is charged with keeping components like the battery, motor and inverter at their optimal operating temperature. The Tesla heat pump warms up the battery in winter, and the Tesla radiator keeps the electric battery cool while charging.

Even though there is no actual engine in a Tesla to generate high-temperature combustion gasses, it is still necessary to control the heat. All this happens with the help of various valves, heat exchangers, fluid pumps and, of course, the coolant itself. While the annual Tesla Model S maintenance cost is fairly simple and budget friendly, there are EV parts that will need replaced as time passes. The cooling system is a prime example of an electric vehicle system that will likely need repair at some point.

Getting Started on Thermal Hose, Control Valve & Water Pump Replacement

Before doing any work on a Tesla Model S or any other electric vehicle, it is important to isolate the high-voltage system. This means making sure the batteries are disconnected and that there is no residual charge in the system. While this particular cooling system repair does not involve the high-voltage electrical system, you should always take care to de-energize any electric vehicle before attempting any maintenance project.

This repair requires lifting the vehicle off the ground to access the undertray for coolant drainage. Remember that a Tesla Model S can weigh up to 4,800 pounds, so pay attention to your lifting equipment rating. Due to the design of the jacking points on a Tesla Model S, the NAPA experts recommend using a 4- or 2-post lift or drive-on ramps to elevate the vehicle. The lack of jacking points with special lifting point pads make lifting a Tesla Model S with a floor jack and supporting the vehicle with jack stands difficult.

Accessing the Component & Drain Coolant

While this repair guide is not meant to serve as a step-by-step DIY instruction, it will give you an idea of what it takes to replace components on a Tesla Model S. Starting with accessing the parts to replace:

1. Roll down the driver’s side window fully. This will prevent getting locked out of the vehicle once the 12v battery is disconnected. 
2. Open the frunk lid. Remove the outer frunk trim panels using your hands (no tools required) by lifting upwards.
3. Remove the cabin filter housing.
4. Disconnect the orange high-voltage interlock loop (also called the fireman’s loop). Do NOT cut the loop, you can simply disconnect it. 
5. Disconnect the 12v battery negative terminal. Wait two minutes for any residual power to dissipate before moving onto the next step.
6. Remove the frunk carpet and surrounding trim panels, including the storage box tub and extension.
7. Remove the coolant reservoir cap.
8. Raise the vehicle off the floor to allow for adequate working area. 
9. Remove the underbelly tray behind the front bumper.
10. Disconnect the left side coolant hose from the battery chiller to drain the coolant. Expect roughly 14 liters of coolant to drain and fill your catch pan. 
11. Once the coolant is fully drained, reconnect the battery chiller hose.
12. Lower the vehicle.

With the components now accessible and the cooling system drained, you can now proceed with the thermal hose, control valve and water pump replacement.

Water Pump to Battery Heater Hose Replacement

1. Locate the water pump to battery heater hose. 
2. Release the hose clamps and remove the hose. 
3. Install the new hose. If you are planning on replacing the water pump as well, only reconnect the hose to the battery heater.

Battery Coolant Pump Replacement

1. Locate the battery coolant pump and disconnect the electrical connector.
2. Release the hose clamps and disconnect any hoses attached to the battery coolant pump.
3. Unbolt the old battery coolant pump from the subframe.
4. Install the new battery coolant pump in the same location as the OE Tesla water pump.
5. Reconnect the coolant hoses and the electrical connector.

3-Way Chiller Bypass Coolant Control Valve Replacement

1. Locate the 3-way coolant control valve just in front of the steering rack and disconnect the electrical connector.
2. Release the hose clamps and disconnect the three hoses attached to the valve.
3. Unbolt the OE 3-way coolant control valve. 
4. Install the new 3-way coolant control valve in the same location as the OE Tesla valve.
5. Reconnect the coolant hoses and the electrical connector.

Reassemble & Refill Coolant 

Once all of the hoses are connected, it is time to refill the cooling system using 14 liters of G-48 compatible Tesla coolant. Check all the hose connections for leaks.

1. Raise the vehicle off the floor again and reinstall the underbelly tray.
2. Reinstall the frunk storage box tub and extension along with the surrounding frunk trim panels.
3. Reconnect the 12v battery negative terminal and orange high-voltage interlock loop.
4. Reinstall the cabin filter housing.
5. Bleed the cooling system. To properly remove any air bubbles from the cooling system, you must initiate the coolant air purge procedure while in Service Mode or using Tesla Toolbox software. Failure to properly bleed air from the cooling system can damage the pumps and cause sensor issues.
6. Reinstall the coolant reservoir cap.

We hope this has taken some of the mystery out of servicing the Tesla Model S thermal management system. For the most part, the procedures are straightforward. Plus, you can find Tesla Model S parts available at your local NAPA Auto Parts store. 

Would you rather let the professionals handle your Tesla repairs? Your local NAPA Auto Care is happy to help. Our ASE-trained technicians have the training, tools and experience needed to fix your Tesla and get you back on the road. At NAPA Auto Care, our work is covered by the NAPA Nationwide Peace of Mind Warranty for 24 months or 24,000 miles.

Photo courtesy of Wikimedia Commons.