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Why is My Heater Blowing Out Cold Air?

Whether we like it or not, winter is still with us for the next 6 weeks, and it looks like the cold temperatures will be around for at least as long. At least you’ve got a nice warm car for the morning commute right? Not if your heat’s broken. If your heater is blowing out cold air, something is definitely not right. Unfortunately the cause of this problem could come from any number of sources, so we’ll touch on a few of the more common ones in this blog.


Why is My Heater Blowing Out Cold Air?

First of all, it’s good to understand how your heater works in the first place. Your engine generates a lot of heat. The heater works by circulating a coolant through the engine which collects this heat. The coolant gets hot, and then passes through a radiator located near the passenger compartment. Fans blow air across the radiator and transfer the heat from the coolant into the passenger compartment, and just like that you’re warm. Now, lets talk about some of the reasons the heat might not be working.

Low Coolant

If the coolant levels are low, the system might not pick up enough heat to heat up the interior compartment. You can use a coolant pressure test kit to check if the cooling system has any leaks.

Clogged/Leaky Heater Core

The heater core can leak or get clogged, which impairs the heaters ability to function. To check if the heater core is clogged, feel the two heater hoses that connect to the heater core tubes, located at the firewall. If one is cold, there may be a clog. If the heater core is leaking, this results in low coolant. If you’re not the first owner of the vehicle, the previous owner may have dealt with the leaky heater core by connecting the hoses to bypass it altogether, which is a quicker fix than fixing the leak at the source. However, in bypassing the heater core, you prevent it from heating.

Trapped Air

If air gets trapped in the system, the heater will blow out cold air. Most newer vehicles route the lines in the cooling system to bleed air out automatically, but in older vehicles trapped air can be a problem.


So what do you do if your heater is blowing out cold air? Come to Auto Stop! We’ll fix your car’s heater in Baltimore and send you on your way warm and toasty.


heater blow out cold air



If you have any questions about our blog, “Why is My Heater Blowing Out Cold Air?” please contact Auto Stop by calling 410-467-7600 or visit AutoStopLTD.com today! You can also follow Auto Stop on FacebookTwitter, and Google+.

Our mechanics are highly trained and use state-of-the-art Automotive diagnostic equipment to pinpoint your particular issues, repair it, and get you back on the road as quickly as possible. We promise to diagnose your auto repair problems in an honest and professional manner and all of our work is 100% guaranteed!

Auto Stop is your local auto repair shop, serving the Baltimore metro area. We are A+ accredited by the Better Business Bureau. We are also an ARI Fleet repair center for all Fleet Repairs.



This entry was posted on Friday, February 7th, 2014 at 4:30 pm. Both comments and pings are currently closed.