Troubleshooting With NAPA: Why Is My Car Heater Blowing Cold Air?
It’s easy to take modern conveniences for granted. An electric coffee pot brewing while you step out of the room. A garage door that opens with the click of a button. Heated air pumping out of the vents into your vehicle on a cold winter’s morning. But what would you do if those conveniences just stop working? Specifically, how do you fix a car heater that is blowing cold air?
Before you panic, let’s double check the obvious. Is your vehicle warmed up enough from a cold start to push out heated air? For your car heater to function properly, the temperature gauge on your dash (which measures the heat around your engine) should read in the middle, not in the blue cold zone or the red hot zone. If you’re too impatient to wait for your vehicle to run long enough to push out hot air before hitting the road, our experts suggest installing a remote starter to give yourself some extra time. Next, let’s check the settings of your internal cabin temperature controls. Has your automatic climate control system set itself to defrost only for the first few minutes? Are the vents on your dashboard open and angled properly to disperse a strong current of air?
If those quick checks were the problem, we promise, we won’t tell anyone. However, if you still haven’t found the answer to ‘why is my heater blowing cold air into my car,’ the next step is to lift the hood to remove any possible obstructions, like leaves and debris, that might be blocking the cold air intake system. Airflow backup could also be caused by a dirty, clogged cabin air filter. A high-quality NAPA Cabin Air Filter keeps the air inside your vehicle clean, while also trapping dust and dirt before it enters your heater core and evaporator. Locate your air filter, and remove it for inspection. If the pleats are clogged with debris, it’s due for a change. As part of a maintenance routine, replace your cabin air filter every 20,000 miles or 12 months, whichever comes first.
Another easy solution to solving a car heater problem is topping off the coolant level. If the coolant level is low, not only will heat not reach your heater core, but the built-up heat not being transmitted properly by coolant could damage your engine. If your coolant level is low, top it off. Be aware, it is critical that you also check for signs of damaged hoses or loose connections that could be leaking.
Another common problem that causes a car heater to pump out cold air is if the control valves in the thermostat are stuck open or closed. A thermostat is a temperature regulator in the form of a valve, situated between the engine coolant outlet and the radiator inlet. If possible, fix the stuck valves, or follow these tips for a full thermostat replacement.
The Fix Is In, And It Won’t Be Pretty
Any quick fix for no heat in a car was mentioned above. If you are still experiencing car heating problems, it is likely a more costly and time-consuming solution. Let’s start with the fan, often called the blower. You should hear the fan running if your heater is turned on, especially full blast. It is possible debris has been lodged or wrapped around the fan, which would cause a tapping noise or popping sound.
If the airflow is weak coming out of your HVAC system, then it is likely a blown blower motor. When you turn on your interior heat, a fan behind the core starts up and blows heat into the passenger compartment. If there is no air current, the solution could be as simple as replacing a fuse or as complicated as replacing the fan itself.
If your heater is blowing cold air, the fan motor might be working, but the water pump, actuator or heater core could be failing. A car heater not working could be due to the vital role the water pump performs. The water pump is typically driven by the accessory drive belt, serpentine belt or timing belt. A worn-out belt can prevent your water pump from operating at peak efficiency. A slow leak from your water pump will cause residue to build up around the pump. Look for coolant trails leading down from the pump or a gunky deposit around the outside.
Still car heater troubleshooting? Actuators are critical to controlling heat, the A/C and even defrost. Knocking, clicking and fluctuating air flow could point to a bad actuator, or two. Cold air output could be an issue if either of the hoses connected to your heater core have become loose. One hose is tasked with transporting hot coolant from the water pump to the heater core. The second hose returns the coolant to the top of the engine. Worst case scenario, if the area inside your vehicle, underneath the dash, is damp from a continuous leak, it is highly likely your heater core needs replaced.
Most drivers are not equipped to fix a car heater blowing cold air. Just to diagnose the problem can require a jack, jack stand and many, many hand tools. The solution, even if simple, could involve specialty hoses, connections and clamps. To replace an entire heater core entails removing several components to get behind the firewall, or even removing the entire dash inside your cabin. Newer model vehicles, packed with sensitive electronics, make things even more challenging. When in doubt, take your vehicle to a local NAPA Auto Care Center near you.
Photo courtesy of Unsplash.
More than 90 years ago, the National Automotive Parts Association ("NAPA") was created to meet America’s growing need for an effective auto parts distribution system. Today, 91% of do-it-yourself customers recognize the NAPA brand name. We have over 6,000 NAPA Auto Parts Stores nationwide serving all 50 states with a unique inventory control system that helps you find the exact part that you need.