Skip to Content

Honda Civic Keeps Overheating at Idle/High or Low Speeds/etc.

Overheating is a common problem for old vehicles, including Honda Civics. Many car parts can rapidly increase the internal temperature, causing it to overheat or smoke, but these issues aren’t exclusive to old cars, trucks, and SUVs. Improper care of a new vehicle can lead to overheating, too.

A Honda Civic overheating at various speeds can often be due to a malfunctioning thermostat. The thermostat regulates the engine’s temperature, and if it’s stuck closed, it prevents coolant from circulating properly, causing the engine to overheat. Replacing the thermostat usually resolves the overheating issue.

Another cause for overheating could be a clogged radiator. Over time, radiators can accumulate deposits that hinder coolant flow, leading to overheating. Flushing the radiator to remove any blockages and refilling it with fresh coolant can often fix the problem and prevent the engine from overheating.

A third reason for a Honda Civic overheating could be a faulty water pump. The water pump circulates coolant through the engine and radiator. If it fails, coolant circulation is compromised, leading to overheating. Replacing the water pump and ensuring the coolant system is properly refilled and bled of air can resolve this overheating issue.

Car tachometer

This article will also teach you the following information about why your Honda Civic keeps overheating:

  • Tips to fix an overheating car to prevent it from recurring
  • Explanations to show why your Civic keeps overheating when you drive
  • Why the coolant keeps draining from the reservoir

Honda Civic Overheating at Idle

Woman frustrated car overheat

There are many reasons your Honda Civic might have overheating problems. Almost every vehicle’s overheating issues are related to the thermostat, coolant, water pump, hoses, or radiator. The radiator’s blower fan is another probable cause, especially if the temperature gauge is getting out of hand.

Here are three reasons your Civic is overheating when idling:

  • The blower fan is supposed to cool the engine once it’s warm enough. If it doesn’t do its job due to a broken piece, malfunctioning sensor, or clog, the fan won’t cool the engine. You’ll notice the vehicle gets very quiet when idling, which could be the lack of a blower fan cooling it.
  • The thermostat is designed to adjust the vehicle’s internal temperature. When it delivers false readings, it won’t open the proper valve. It stops cooling the engine when you’re stopped in traffic or idling in the driveway, increasing its temperature and leading to overheating.
  • If the radiator’s fan is damaged, it won’t cool the engine. The radiator’s fan is supposed to spread cold air over the engine, but if it’s chipped, blocked, or stuck, it can’t get the job done.

Honda Civic Overheating After Long Drive

Woman with a car engine that has overheated

Long drives can be bad for any vehicle. They’re not too detrimental for a brand-new Civic, but any car with old internals will face a series of issues after driving on a road trip or anything longer than two or three hours. You should ensure all of the fluids are at the correct level before leaving on the trip to prevent anything from happening.

One of the primary reasons your Honda Civic overheats after a long drive is the coolant might be leaking. If it’s leaking, there’s nothing to cool the radiator. You might’ve noticed the coolant levels were full before and after the drive, so how could there be a leak?

Check the reservoir! Often, the radiator will have enough coolant, but the reservoir will be drained after a long drive. This discovery indicates there’s a leak somewhere in the system. The radiator’s coolant reservoir provides a slow trickle of leftover coolant in case the radiator runs out. However, it shouldn’t drain everything after a few hours of driving.

Honda Civic Overheating at High Speeds

Car speedometer

Is your Civic overheating every time you accelerate too quickly? You’re probably experiencing a cracked or leaking radiator, broken fan, or damaged hose. Kinked hoses can limit the coolant’s flow to the radiator, preventing it from supplying the correct amount of liquid. If it’s not cooled, the vehicle will overheat.

Keep an eye on the temperature gauge. Many overheating vehicles get warmer inside as the meter increases. The thermostat might be malfunctioning, which supplies improper readings and skyrockets the engine’s temperature. This issue is especially relevant when you’re driving at high speeds.

Always let the engine cool down before you inspect the radiator. There are scorching hot liquids inside that can cause severe burns. Once you give it at least an hour to cool off (it’ll take longer on hot days), you can remove and inspect the radiator’s cap. Look for leaks or fractures along the radiator. Any small cracks can cause a host of problems.

If your vehicle overheats while you’re accelerating, don’t push your luck. Pull over to the side of the road, let it cool down, and assess the situation. Pushing the vehicle beyond its limits and overheating the engine can cause fires that lead to irreparable damage.

Honda Civic Overheating When Heater Is On

Car heater controls

Turning on the heater shouldn’t increase your engine’s temperature. The heater’s purpose is to keep you warm, not overheat your Civic. However, low coolant levels can make your car overheat right when you turn on the heater. Let’s explain the main reason your car is overheating from activating the heater or opening the vents:

  • Low coolant levels prevent the radiator from cooling the engine. Small clogs aren’t enough to stop the coolant from forcing itself through the system, but large clogs will drastically limit the flow. If you don’t have enough coolant and there’s a clog, your radiator has nothing to work with.
  • When you turn on the heater and open the vents, the system redirects fluids, letting it heat your vehicle while cooling off the engine. However, if you don’t have enough coolant or there’s a clog in the radiator, the redirect can overheat the engine because there’s not enough fluid for both systems.

As you can see, this simple problem is often solved by declogging the radiator and adding coolant. Always check the coolant levels if your vehicle keeps overheating.

Honda Civic Overheating With New Radiator

Car coolant

Let’s assume you recently purchased a brand-new radiator for your vehicle, but it continues to overheat. You’re probably frustrated because radiators aren’t cheap, nor is the repair price if you got it from a mechanic’s shop. So, why is your Honda Civic’s new radiator overheating?

Here are several explanations:

  • There’s a leak somewhere along the hoses. Whether there’s a small crack, a kink, or a loose connection, your car’s hoses and leak enough coolant to overheat the engine. It doesn’t matter how new your radiator is; It can’t function without enough coolant in the reservoir or tank.
  • You need to add more coolant to the radiator. If your new radiator is overheating, ensure there’s enough coolant (and make sure it’s the right type, too). When you’re done, inspect the reservoir to ensure there’s enough coolant there, too. Once you have both of them checked, you can head to the final explanation.
  • There’s a clog somewhere in the system. Clogged air filters, blower fans, and almost anything else in the vehicle can cause overheating. There needs to be enough airflow to prevent overheating. Debris clogs every part of the system, so make sure you follow the manufacturer’s recommended inspection guidelines.

Honda Civic Overheating Randomly

Car engine overheating

Random overheating is often the most frustrating kind. It’s unpredictable, so you don’t know which situations you should avoid. Some drivers know not to go too fast, while others know they have to leave their heaters off. Unfortunately, random overheating is much harder to diagnose and repair.

It’s not uncommon for random overheating to be attributed to low coolant levels. If you have a full radiator reservoir, it’ll trickle enough coolant to keep the engine cooled down. However, a leak will limit how often it cools the system. There will be enough for many hours, but it’ll randomly cut off if it runs into a clog.

Another reason is the blower fan might be going bad (or the car’s battery). If the battery flickers and can’t operate the fan, it’ll work sporadically. When it’s running and blowing, you’ll be good to go, but when the battery doesn’t supply enough power, the blower fan will shut off. The result is an overheated engine. Check the battery and blower fan to ensure they’re both functioning as they should.

Honda Civic Overheating Coolant Full

Car coolant fill

If you have a new radiator, there are no cracks, and the coolant is topped off, what could be wrong? It seems like you’ve checked every part of the system but keep in mind cars have hundreds of components. There are three parts that could cause your Civic to overheat, even if the coolant levels are full:

  • The water pump might be malfunctioning. The water pump’s job is to bring the liquid from the radiator to the engine. If it’s not doing what it’s supposed to, the coolant won’t be moved to cool the system. You could have a brand-new radiator, reservoir, and topped coolant, but a blown water pump can ruin it all.
  • The blower fan could have a crack or might be damaged. If it’s broken, full coolant levels can’t do anything to fix the problem. The blower fan is supposed to cool the engine since it’s a lengthy, high-energy process. When it stops working, you need to get a new one if you want to drive faster than a couple of miles per hour.
  • Check the thermostat. It determines how much coolant is needed at any given time. If it’s not supplying enough coolant, your vehicle will overheat. Thermostats are one of the simplest components in a vehicle, but they’re also crucial to its operation. If your thermostat is shot, your radiator, water pump, and coolant won’t work.

Honda Civic Losing Coolant Overheating

Car tachometer

A leak almost always causes rapid coolant loss. The system rarely demands enough coolant to drain the system in a short time. Unless you’re driving hundreds of miles per hour for several days in a row, there’s probably a leak somewhere in the system; But what can cause the coolant to drain?

Check all of the hoses between the coolant, water pump, and reservoir. Small trickles can drain enough coolant to overheat the Civic’s engine. Inspect the radiator to look for small cracks. Old radiators are known for having hairline fractures near the top since all of the pressure goes near the cap. On that note, remove the cap (when it’s cold) and look for cracks. Make sure there’s an O-ring to prevent coolant loss.

Another thing you should do is look under the vehicle after driving for a while. Check for droplets below the radiator and on the car’s grille. Running the air conditioner will cause moisture loss, but the coolant will be thick and colored.

Honda Civic Overheating and Blowing Cold Air

Car AC button

Most overheating cars increase the cab’s interior temperature, but an overheating vehicle will blow cold air in some situations. It’s likely caused by a malfunctioning water pump. As you read earlier in the article, the water pump is supposed to move liquid from the radiator to the engine to cool it off. If it’s clogged or damaged, it won’t drop the temperature.

So, why would the car blow cold air if it’s overheating?

A blockage can redirect fluid and airflow, causing the cold temperature to go into the cab rather than the engine. You’ll stay cold inside the car, but the engine will overheat. Check the temperature gauge if your vehicle gets too cold; It’s probably rising as you get colder by the minute.

Furthermore, the thermostat assumes it’s doing the right job since it’s directing enough coolant. When it recognizes the engine isn’t cooling down, it pumps more coolant than needed, draining the coolant levels and overheating the radiator.

Honda Civic Overheating in Traffic

Car driver road rage

If your Civic is overheating when you’re in traffic, there’s probably damage on the blower fan, thermostat, or coolant reservoir. Inspect the radiator to ensure there aren’t any cracks, then look at the hoses and look for kinks. Loose brackets can leak coolant, too. Tighten the brackets at the end of each hose with a flathead screwdriver.

Thermostats are relatively affordable since they’re small and cheap to produce. Most mechanics will charge very little labor to replace a thermostat. It’s often less than $150 unless you can DIY the project. While you’re at it, get a new radiator cap. You can often find them cheaper than $20, and they require about one second to install.

Another problem could be a closing valve. If it thinks the system is cooled down when you stop in traffic, it’ll stop the water pump from cycling coolant through the radiator and engine. Your vehicle will get hot when it’s stopped, but it’ll cool down as you accelerate.

Honda Civic Overheats on Highway

Highway traffic

Highway overheating is the same as overheating when you’re accelerating or driving in traffic. It’s a result of not enough coolant, an overwhelmed water pump, or a faulty thermostat. Any of these problems cause the car to overheat because the cooling system isn’t doing what it’s supposed to.

When your vehicle overheats on the highway, follow this step-by-step process:

  1. Turn on your hazard lights and take your foot off the gas. Don’t slam the brakes, or you’ll risk an accident.
  2. Slowly pull over to the side of the road when it’s safe to do so.
  3. Turn off the ignition and ensure the meter goes down. If it doesn’t, exit the vehicle and move far away. It might start smoking or flaming.
  4. Call a tow truck or friend to come to pick you up. If you want to work on the vehicle, wait to add coolant and lift the hood until it cools down.

Honda Civic Overheats When Stopped

Car speedometer

Honda Civics overheat when they’re stopped if the thermostat isn’t supplying enough coolant to the engine. It could also be caused by a closed valve in the water pump that won’t push or pull cooling liquid from the radiator. Pull over, remove the keys, wait for it to cool off, and add enough coolant to get home or to a mechanic’s shop.

Honda Civic Overheats Going Uphill

Car driving up hill

Driving uphill requires a lot of power from your vehicle. It demands more coolant, power, fuel, and oxygen. Most Honda Civics have what it takes to drive uphill, but older models have trouble with the cooling system. As it pushes the engine harder than usual, it requires additional coolant. As you know, a lack of coolant overheats the engine.

A small clog can wreak havoc on a Civic’s engine because it doesn’t let the water pump move coolant to the radiator. When the radiator’s temperature spikes, it can blow the cap off the top. You might hear a loud thump under the hood; It’s the sound of the cap shooting off the radiator and hitting the engine.

The best way to stop this from happening is to top off the coolant levels, repair cracks, replace hoses, and unclog all of the components. A clog in the blower fan, fuel assembly, air filter, radiator, hoses, water pump, or anywhere in between will be very influential in your car’s demise as you climb a steep hill.

Keep an eye on the temperature meter if you’re going uphill in an old car. If you know your vehicle is prone to overheating, it’s not worth the risk. A few minor repairs can be the difference between a few hundred dollars and replacing the vehicle. Severe overheating damages the engine, transmission, and all of the aforementioned parts found throughout the cooling system.

Related Articles

Honda Civic Battery Keeps Dying/Draining

Honda Civic Trunk Won’t Open/Close/Unlock/Lock

Honda Civic Speedometer Not Working

Honda Civic Stalls While Driving / Cold / Hot / Accelerating

Honda Civic Rattling (Hood/Timing Chain/Engine/etc.)

Honda Civic Won’t Start (How to Fix)

Honda Civic AC Problems (Not Cold/Not Turning On/Intermittent)

Honda Civic Key Not Working (Won’t Start Car/Turn/Unlock)

Honda Civic Display Not Working (Apple Play/Android Auto)

Honda Civic Won’t Shift/ Stuck in Park/Drive/Neutral

Honda Civic Gas Tank Won’t Open/Close/Noise/Leak

Honda Civic Hood Won’t Open/Close/Latch/Lock

Honda Civic Heater Not Working

Honda Civic (Alarm, Radio, etc.) Won’t Turn Off

Honda Civic Doesn’t Accelerate (Rough/Loud/Noisy/etc.)

Honda Civic Brake Leaking

Honda Civic Fuel Injectors/Pump Not Working

Honda Civic Windshield Wiper Fluid Not Spraying

Honda Civic Gear Shift Stuck

Honda Civic Alarm Won’t Turn On/Go Off/Keeps Going Off

Honda Civic Seat Belt Won’t Work/Retract/Lock/etc.

Honda Civic Brake Won’t Work/Move/Release

Honda Civic Radio Not Working (Won’t Turn On, Turns Off, etc.)

Honda Civic Windows Not Working/Keeps Going Down

Honda Civic Keeps Overheating at Idle/High or Low Speeds/etc.

Honda Civic Noise When Accelerating / Turning / Driving

Honda Civic Lights Won’t Turn Off (Brake/Airbag/Parking/etc.)

Honda Civic Door Won’t Open/Close/Lock/Unlock

Honda Civic Apple CarPlay Not Working

Honda Civic Bluetooth Not Working

Honda Civic Keyless Not Working

Honda Civic Fan Not Working

Honda Civic Brake Light Not Working

Copyright protected article by Know My Auto and was first published on Mar 18, 2021. .

Honda Civic Camera Not Working

Honda Civic Tire Pressure Light Troubleshooting

How To Reset Honda Civic Functions

Honda Civic USB Port Not Working

Honda Civic Airbag System Problem

The copyright owner of this article is and was first published on Mar 18, 2021..

Honda Civic Speakers Not Working

Honda Civic Radiator Fan Not Working (How To)

Honda Civic Clicking Noise (What Is It – How to Fix)

Honda Civic Blower Motor Not Working (How To)

What Can You Put On A Honda Civic?

Honda Civic Tail Lights Not Working

Honda Civic Monthly/Annual Gas/Fuel Cost

Honda Civic Apple CarPlay Keeps Disconnecting

How to Clean Honda Civic Headlight

Honda Civic CarPlay Reset (How To)

KnowMyAuto is the sole owner of this article was published on Mar 18, 2021 and last updated on .

How to Clean Your Honda Civic Air Filter