Toyota and Lexus air conditioning odor – prevention and repair of foul air

A common concern Toyota and Lexus owners in Minnesota complain of is a foul odor from their vehicle upon startup, likened to a wet dog, mold or a damp basement. Toyota and Lexus offer several solutions to this problem, including upgraded cabin air filters and a special cleaning kits for the air conditioning system. First, what causes the smell?

Evaporator core from a Lexus

The most common source of odor from the heating and air conditioning is moisture accumulating on the evaporator (removed from the car, above). The evaporator is cooled by the air conditioning system, forming condensation on its fins as it operates, draining out an orifice at the bottom of it’s housing. This is the water you see under your car when you sit with the A/C running. Over time this moisture can lead to a small amount of mold growth and a foul smell as air first passes over it right after you fire up the fans. Toyota and Lexus make a special kit for this cause of odor:

Toyota and Lexus A/C refresh kit

The A/C refresh kit is Toyota and Lexus’s repair for the odor via alcohol-based cleaners, the first step injected under pressure (in the form of a foam) up the drain pipe for the evaporator, filling the evaporator’s fins and housing with alcohol-based foam that cleans and sterilizes whatever it touches, later reverting back to a liquid and draining back out. The second step is a spray, applied to the fresh air intake at the cowl at the base of the windshield, while the vehicle runs with the heat on. This disperses the cleaner through all of the air vents, cleaning and deodorizing them. The alcohol cleaner takes about an hour to dissipate – we don’t recommend driving the car in the meanwhile due to the fumes.

CARspec also recommends replacement of the cabin air filter when a guest has odor issues or to prevent them. The filter is the first line of defense against odors (as it filters incoming air of pollen, dust and the like). We also recommend owners set their A/C to fresh air mode from recirculate before they shut the car off, allowing moisture that would be normally trapped in the system to evaporate through the fresh air opening and vent outside the car. As Eden Prairie and Chanhassen’s Toyota and Lexus specialist repair shop, we hope this helps an owner cure a smelly car and get that “like new” smell back.