Don't let a bad heater freeze you out of winter fun!
It’s not quite a northeast Ohio winter right now, but it’s getting there. After you’ve switched to your hard top, stocked any emergency supplies (because we know you can’t resist playing in the snow), and checked your tire pressure, give your heater a test run. If it’s not blowing hot air, this will be a long winter.
If your heater is producing heat when it isn’t cold outside, but blows lukewarm air when you need heat most, you might be dealing with a stuck thermostat or a heater core that needs flushed.
If your top radiator hose or heater hoses aren’t getting hot, you may have a failed thermostat. For some thermostats, the failsafe is ‘open’, so when it fails it will stick open, and that’s not good. Continual cold weather also helps keep the engine cool, so that could also be a reason why your temperature gauge reads in the ‘normal’ range.
Make sure your thermostat reads 195°F and is working properly. You can do this by turning your heater all the way up and letting it run at full blast for a few minutes. Slide the stem of an instant read thermometer into your heater vent to get the temperature.
If you need to purchase and install a new one, some thermostats have a weep/bleed hole drilled in, which helps bleed air out of the coolant system. This allows for a tiny amount of coolant flow in case of a stuck thermostat.
Plugged Heater Core
Over time, your heater hoses can build up with gunk (yes, that’s a technical term) that prevents heat from coming through. If your heater is blowing lukewarm air and your thermostat is working fine, you heater core may need reverse flushed.
We found a great step-by-step DIY guide to flushing out your heater core. It’s easy enough that you can do it right in your driveway with minimal equipment. Pay special note to Step 5, which uses a cleaning agent to get any remaining debris. It is imperative that you only use a cleaning agent that is safe for aluminum. The heater core and hoses are all made from aluminum, and any leftover cleaning agent that isn’t safe for aluminum will eat away at your equipment. Not a good thing.
Check and Test Coolant
When you flush, check to see if any coolant coming out has a rust color. That’s a good indicator that your coolant likely needs changed. This video shows other great ways to test your coolant/antifreeze, and this follow-up video will show you how to flush and change your coolant.
One Last Trick
In a pinch, one good way to heat up your engine faster without over heating it is to put a piece of cardboard or corrugated ‘plastic cardboard’ in front of your radiator so it covers about half to three-quarters of where the air flows through the radiator. This will help the heater heat faster and maintain better.
Having a good working heater in the winter is critical for the health of your engine, as well as the health of the driver and your passengers. If you’re the adventurous type and plan to go off-road this winter, a properly working heater becomes a safety factor in the event you get stuck and have to wait for help. Take good care of your heater, and it will take care of you.