Cabin Uncomfortable? What to Expect With Heating System Repairs

Brrrr!!!!! Not only do your pants freeze to your seat, but no warm air blows out of your vents! What to do? Should you take your car in for repairs? After all, why not wear just more warm clothes, right?

Not entirely. Problems with your heater affect more than your personal comfort. In this blog post, we’ll show you how to detect the major symptoms of heater problems, understand the most common causes, and then walk you through what an automotive technician inspects.

One Quick Check

Before worrying about heater issues, make sure you’ve been driving for at least five minutes. This ensures the coolant is receiving heat from the engine to transfer to the passenger cabin. However, if you’re still experiencing problems with your heating system, read on.

How Do You Know You Have Heater Problems?

Apart from no heat, what else points to a problem with your heater system?

• Weak or inconsistent airflow
• Unusual sounds such as screeching, clunking or metal-on-metal friction
• Sweet smell not caused by spilled pop that’s dried between the seats*
• Other odd odours
• Floor mats damp for longer than they should be*

*If a sweet smell is wafting out of your vents, or your floor mats are damp for longer than is reasonable, even in winter, you may have a coolant leak. Coolant vapours are dangerous to humans. Have your car towed to your nearest garage immediately.

Share with your automotive tech the symptoms you’ve been experiencing, so they can better diagnose the issue.

What Can Cause a Problem With Your Car’s Heater?

The heating system in a vehicle is a complex system that involves the engine, the electronic control module (your car’s computer), hoses, valves, thermostat, coolant, and more. Your automotive technician will inspect the system to find out why heat isn’t blowing into the passenger cabin. 

Broken Air Conditioner

This may sound counterintuitive, but a malfunctioning air conditioner can contribute to your heater issues. The air conditioner removes moisture from the air. The most obvious way this helps is with visibility: no moisture, no fog on your windshield.

Contaminated or Low Coolant

Despite its name, coolant is not just for air-conditioning. It transfers heat from one location to another. So, if the coolant in your vehicle is dirty, or your vehicle doesn’t have enough, it can’t transport heat into the cabin.

Broken or Malfunctioning Thermostat

Unlike your home, where the thermostat is on the wall, your vehicle’s thermostat isn’t an easy-to-find control pad. But like your thermostat at home, you can feel its effects when it malfunctions.

The most common problem you’ll feel with the thermostat is that, despite having turned up the temperature in your car as much as possible, you feel air-conditioned air instead.

Heater Core Issues

Any part of this important component can break down. Debris in the system can also clog it. If this is your problem, you’ll feel a little warm air coming from the vents. This is residual heat from the engine, not heat produced by the heating system.

Broken Blower Fan

This electric component can wear out over time. When it doesn’t work, you’ll notice weak airflow, possibly none at all. The little air you do feel may also be cold.

Blend Door Stuck in Cold Position

The blend door blends hot and cold air to create the temperature you’ve set on your dash. If it remains in the cold position, for example, hot air won’t blow through.

Damaged Heater Hoses

These hoses carry coolant to and from the engine. Old and dried-out hoses can leak in colder weather, which causes them to shrink. But damage and leaks can occur in any season.

Clogged or Full Cabin Air Filter

If you didn’t know you had a cabin air filter, then this easy fix could cause your heating troubles. You can usually find this filter behind the glove compartment. It collects dust, pollens, and other debris so your cabin air is fresh and clean. Your automotive technician can switch it out in a jiffy.

What a Mechanic Does When Inspecting Heating Systems

We’ve compiled a list for you that outlines what an automotive technician may do to diagnose the problem you’re having with your vehicle’s heating system. Depending on the symptoms you report, they may prioritize some tests and inspections over others.

• check coolant color and level
• test antifreeze
• perform cooling system pressure check
• thorough system inspection, including hoses, radiator, reservoir, fan, thermostat, and several smaller parts
• assess the heater core
• inspect blower motor and air flow
• listen for unusual noises
• replace the cabin air filter 
• verify that the air conditioner is working

Ask Questions

When you have your vehicle inspected at your local NAPA AUTOPRO service centre, ask our friendly technicians any questions you want about your heat system issues. They will be more than happy to answer them for you.