How can I test a car’s AC evaporator?

I’ve noticed a strange, almost sweet, smell coming from my car’s vents when the air conditioning is on. I drive for Lyft and a passenger told me there might be a leak in the AC evaporator. How can I test a car’s AC evaporator?

It sounds like your passenger may be right! The sweet smell filling your car could be the result of refrigerant leaking from the evaporator. You can test the car’s evaporator at home, but you’ll need specialized tools.
To check for leaks in the evaporator, you’ll need:
  • AC gauge set
  • Refrigerant leak detection dye
To test the evaporator, follow these steps:
  • Attach the AC gauge set to the service ports. The blue hose connects to the low-pressure port. The red hose goes to the high-pressure port. You can use the owner’s manual and gauge instructions for further details.
  • Add one can of refrigerant containing leak detection dye to the low-pressure side with your air conditioning running at the coolest setting.
  • Let the car run for 15 minutes to circulate the refrigerant and dye.
  • Check the condensation tube under the vehicle for any dye that has collected or dripped onto the pavement.
If dye is present, there is a leak in the evaporator. You’ll want to take your car to a mechanic for service. If no dye is present, but the smell isn’t disappearing, it’s also worth a trip to your mechanic.
Since you drive for Lyft, ensure you have the proper car insurance for ridesharing.
If you’d like to explore rideshare coverage or just want to save money, download the Jerry app. A licensed broker that offers end-to-end support, the Jerry app gathers affordable quotes and helps you switch plans. The average user saves $879 a year!
Jack Walsh
Answered on Nov 19, 2021

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