Car engines should be cool within the first hour after you shut them down. If the engine remains hot for over 2 hours, there’s something amiss with the cooling system.
Low coolant is one of the main reasons your car engine remains hot for more than two hours after shutdown. Other parts of the cooling system, like the cooling fan and radiator, may also be responsible. I suggest you diagnose your vehicle further to pinpoint the actual cause.
The article should help you determine why your car engine remains hot hours after it has been switched off. Therefore, read on.
Why Is My Car Engine Still Hot After 2 Hours?
I find it relevant to learn about the engine temperatures, including how long it takes to cool. This information is necessary for various reasons, including maintenance. For instance, you need to know how long to let the engine cool before changing the spark plugs.
As mentioned earlier, most engines cool down within the first hour after combustion stops. However, the time at which an engine cools down depends on various factors. They include-
- Engine size
- Engine material and insulation
- Surrounding temperature
- How long did the engine run before it went off
However, modern-day engines run at high temperatures, some even above 200° Fahrenheit (93°C.) However, they can cool down faster with the help of the cooling system.
Therefore, when a vehicle takes hours before cooling, the cooling system is often responsible as most times the engine has overheated. Therefore, most of the things to check in this scenario should be on cooling.
Following are various things that may be causing your car engine to remain hot after 2 hours.
1. Low Coolant
The coolant relieves the engine from heat as it runs, allowing it to cool faster. If the coolant is low, the car’s engine cannot dispense heat effectively and overheats.
The coolant usually runs low due to a leak, mostly at the points where the hoses connect. The seal at these joints becomes weak and allows the coolant to leak.
Solutions
The solution to a low coolant is to refill it to the required levels. However, before adding coolant, you must fix all the leaking points to prevent further leaks. Get a mechanic to diagnose the cooling system for leaks.
Follow the steps below to refill the cooling system
- Step 1. Turn off the vehicle and allow the engine cool.
- Step 2. Check whether you need to add the coolant to the radiator or reservoir.
- Step 3. Locate the cap and remove it. You may need to use a funnel to avoid getting the coolant sprayed all over the engine.
- Step 4. Add your preferred coolant type to the cold fill line.
- Step 5. Turn the vehicle on and continue refilling to the hot fill line.
- Step 6. Put back the cap.
- Step 7. Monitor the coolant level for the next few days and top up if needed.
You can hire a mechanic to check leaks and refill the cooling system. These repair services cost between $100 and $200.
2. Faulty Cooling Fan
A cooling fan, or a radiator fan, helps the engine cool by pulling cold air through the grill. The fans prove effective, especially when the vehicle is driven at low speeds or idles.
If the fan, or fans, are not working, the engine cannot disperse heat effectively and overheats. Also, the radiator fins cannot cool the hot coolant passing through, resulting in reduced cooling.
Solutions
You may be able to repair a faulty fan, but I prefer replacing them to prevent further problems. Replacing a radiator fan is an energy and time-consuming task, but doable. Follow the steps below to replace a faulty fan.
- Step 1. Remove the plastic cover over the radiator by removing all the grommets securing it.
- Step 2. Disconnect the upper radiator hose after unscrewing its retainer bolts. On some vehicles, you may need to remove it.
- Step 3. Unplug the electrical connectors connecting to the radiator and the radiator fan. Also, disconnect the battery for further safety.
- Step 4. Unscrew the top, usually two screws holding the radiator in place.
- Step 5. You may also need to remove the car’s battery and engine cover in some vehicles.
- Step 6. After clearing enough room, wiggle the fan or fans out of the radiator.
- Step 7. Replace the fan motor or get a new fan.
- Step 8. Install the fan to the radiator.
- Step 9. Screw the radiator back on and plug in the electrical connectors you removed earlier.
- Step 10. Connect the upper radiator hose.
- Step 11. Replace the radiator cover. Also, replace the engine cover and the battery if you removed them earlier.
Hiring a mechanic to replace the radiator fan will cost between $400 and $1,000.
3. Thermostat Is Stuck
A Car’s thermostat allows the engine to cool faster by recycling the coolant running in it. It then opens up when the engine reaches its operating temperature allowing cold coolant to maintain temperatures.
However, a thermostat can become stuck due to corrosion and age and fail to open. In this instance, it doesn’t allow cold coolant to the engine, which leads to overheating.
Often a failed thermostat will cause the check engine light to illuminate and return a thermostat-related code, like code P0128 or P0125.
Solutions
The best solution to a stuck thermostat is to replace it. I usually prefer to replace them myself rather than hire a mechanic. Replacing a thermostat is easy, and you can also do it by following the steps.
- Step 1. Turn off the vehicle and allow it time to cool.
- Step 2. Drain at least half of the coolant to prevent spills.
- Step 3. Locate the thermostat housing.
- Step 4. Unscrew the bolts holding the housing and remove it
- Step 5. Using pliers pull out the thermostat
- Step 6. Scrap the residue of the gasket from the previous thermostat
- Step 7. Install the new thermostat and install its gasket
- Step 8. Install the housing
- Step 9. Refill the coolant
- Step 10. Test the new thermostat
If you’re uncomfortable replacing the thermostat, you can hire a mechanic. You can expect to pay between $200 and $500 for this repair, labor included.
Other possible reasons your car engine may remain hot after 2 hours include;
- A faulty water pump – a faulty water pump is unable to push coolant and can allow the engine to overheat. The serpentine belt, which turns the water pump, may also be broken. Hire a professional to diagnose and fix it.
- A Clogged Radiator – A clogged radiator prevents the coolant from cooling, allowing the engine to overheat. Clean the radiator with pressurized water.
Concluding Notes
If your car’s engine is still hot after 2 hours, there’s something wrong with its cooling system. To fix this, you need to diagnose the various parts of the cooling system and repair or replace them.
Most of these parts are easy to diagnose and replace. You can do the replacements by following the steps provided in the article and save labor money. However, if you’re uncomfortable doing it, hire a professional to diagnose and fix the faulty part.
Resources
https://www.consumerreports.org/cro/news/2010/07/what-to-do-if-your-car-overheats/index.htm
https://www2.gov.bc.ca/assets/gov/farming-natural-resources-and-industry/forestry/bc-timber-sales/ems-sfm-certification/business-area/chinook/antifreeze_msds.pdf
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