Cleaning A Car A/C Evaporator Without Removing It

Car repair and cleaning concept - car engine close-up, wiping parts under the hood

An evaporator, like other air conditioning components, is susceptible to becoming dirty, which can impact its performance. But did you know that cleaning a car A/C evaporator might be possible without actually having to remove it?

Inspect the Vehicle’s A/C System

The purpose of inspecting the vehicle’s A/C system is to locate its evaporator assembly. It is typically situated along with the firewall which separates your vehicle’s passenger area from its engine compartment. The evaporator will be housed in a plastic container that extends from a firewall and has a heat blower connected to it. Taking it off is the best way to gain access to the air conditioning’s evaporator core.

Find the Evaporator Core

In the majority of automobiles, the evaporator core consists of the resistor block which is mounted either to the side or on top of a heater box. It can be removed for fast access and you also have the option of extracting its blower fan.

Apply Cleaner to the Evaporator Core

Once you’ve found the vehicle’s evaporator core, you’ll now need to eliminate the contamination. To do this you’ll want to take a specialty cleaner and spray it onto the core of the evaporator and be sure to cover the entire surface. The majority of these specialty cleaners appear as foam which will attach itself to the surface of the heater box which cleanses them. Once you’ve filled up the entire area using your cleaner foam, you’ll want to let it sit for approximately thirty to sixty minutes which will give the foam enough time to do its work. You’ll notice it transform into liquid after which it will flow away via the drain openings.

Rinse the Spot Lightly Using Clean Water

Once the foam/liquid has drained away completely, next you’ll want to rinse your evaporator core, which should be done using clean water. The best way to apply it is via water hose but you don’t have to use a lot of pressure, as a light spray will suffice. Some people prefer using a water bottle with a simple spray nozzle attached to it.

Seal Your Heater Box

Now that you’ve cleaned and rinsed everything, you’ll want to put everything back in place. If you extracted the blower fan, you’ll have to reinstall it, and those that did any drilling will need to use sealant to close the opening. Once everything is reassembled, you’ll want to turn on the vehicle and let it sit for about thirty minutes with the heat set on hot and its blower turned up to the highest level so that the wet areas are completely dry.

Return and Fix Your Resistor Block

The final thing you’ll need to do is replace your resistor block and ensure it’s fixed into the correct position. It should also be noted that when rinsing the evaporator core after you’re finished cleaning it, make sure that the water never touches the other components otherwise you may fail to dry them thoroughly even when running the heater for half an hour which could result in the A/C system becoming damaged.