I have experienced a sudden spike in my engine temperature gauge, and it returns to normal shortly after. This certainly is a cause for concern, as it indicates an underlying issue with your vehicle.
So, why does the engine temperature spike and then return to normal? The main culprits in most cases are as follows.
- Thermostat malfunction
- Blocked radiator
- Coolant system issues
- Driving conditions
- Electrical fan issues
- Worn or damaged belts
- Air in the cooling system
In this article, I will discuss the possible causes of engine temperature spikes, how to diagnose the problem, and how to fix it. Let’s get started.
Engine Temp Spikes Then Return Normal | Causes With Solutions
If you notice the engine temperature suddenly rising and dropping, it’s a sign that something is amiss with the engine’s cooling system. This situation can result from a range of factors, including the following.
1. Thermostat Malfunction
The thermostat is like a sensor in your engine that manages hot water going into the engine. Inside it, there’s a spring that opens the sensor when the engine is at the right temperature.
But, if the thermostat is broken or stuck, it can’t tell when the engine is hot enough, and that makes it get even hotter.
So, the engine overheats because too much heat stays inside.
How to fix?
A bad thermostat can show itself with signs like less engine power, unusually loud engine noises, and incorrect thermostat readings.
If so, replace the bad thermostat with a new one with the help of a professional mechanic.
You can watch this video to understand how to troubleshoot and replace a bad thermostat.
2. Blocked Radiator
The radiator’s job is to cool the hot coolant that goes through the engine. If the radiator gets clogged or dirty, it slows down the coolant in the cooling system, meaning that less coolant will go into the engine.
This makes the engine get too hot and have temperature spikes, causing the engine to misfire. Other symptoms of a blocked radiator include steam coming out of the car hood and engine misfiring at low rpm.
How To Fix It?
- Inspect the radiator for any indications of harm, such as leaks, cracks, or blocks due to dirt and grime. Should you discover any damage, visit a professional mechanic to install a new one.
- Use distilled water when mixing coolant to prevent mineral deposits.
3. Air In The Cooling System
When there’s not enough idle, it can cause an increase in engine temperature because the engine continues to generate heat even when not actively moving.
However, modern engines are designed to handle idling within normal operating temperatures. Excessive idling, though, can contribute to long-term wear and fuel consumption coolant, or when you don’t get rid of air bubbles after adding coolant or doing repairs, you can get air pockets trapped in the cooling system.
Having air in the cooling system stops the coolant from moving the right way, creating hot spots in the engine and making the temperature go up.
How to Fix it?
Bleed the air to remove the air bubbles. To bleed air from a cooling system and purge the air out, you can follow the steps below:
- Park your vehicle on a level surface and allow the engine to cool down completely.
- Locate the radiator cap or coolant reservoir and open the cap slowly.
- Start the engine and let it idle. Allow the engine to warm up and reach its operating temperature. This will help to circulate the coolant and expel any trapped air.
- Monitor the coolant level in the radiator or reservoir. Add more coolant as necessary to maintain the proper level.
- Look for air bubbles or gurgling sounds in the coolant.
- Squeeze the upper radiator hose or coolant hoses gently to help release any trapped air.
- Continue to monitor the coolant level and add more coolant if needed.
- Keep the engine running and observe the temperature gauge.
- Once the engine has reached its operating temperature and the coolant level stabilizes, replace the radiator cap or coolant reservoir cap securely.
- Turn off the engine and allow it to cool down.
- After the engine has cooled, check the coolant level once again and top up if necessary.
- Repeat the bleeding process if necessary.
4. Driving Conditions
Driving situations, such as going uphill, speeding up quickly, or carrying heavy loads, can make the engine work harder and cause brief temperature rises. As your engine works at higher RPMs to keep up with your need for speed, it generates additional heat.
This leads to a temporary increase in temperature. However, it’s nothing to worry about as the engine cools down when you reduce your speed or switch to lower gears.
5. Electrical Fan Issues
If the radiator fan in your car is not working right, it can make the engine get too hot and then cool down fast. The fan usually has two speeds: low and high.
Normally, the high speed kicks in when your car is getting too hot or when you use the air conditioner. If the fan doesn’t turn on and off the way it should, it means the fan’s motor is not working well, or the fan relay is not good.
How to fix it?
- Check that the electrical connections to the fan are firmly attached and without rust. Also, make sure that all connections to other components are secure and clear of dirt or corrosion.
- Fix or change any wiring or connectors that are damaged by a mechanic.
- If you’re uncertain about diagnosing and resolving the problem, it’s advisable to have a mechanic inspect and repair your car.
6. Worn or Damaged Belts
The serpentine belt makes many things work in your car’s engine, like the water pump. When it’s loose or broken, there is not enough power to move the coolant into the engine, which leads to the engine getting too hot. If there’s a broken V-belt in an enclosed cooling system, it can also make the temperature go up quickly.
How to Fix?
For a thorough check-up and repairs, it’s a good idea to bring your car to a professional mechanic.
How to diagnose a broken V-belt
To figure out if a V-belt is broken, you can get informed through auditory inspection and visual inspection. Here are signs and ways to check, as shared in the resources:
- Examine the belt surface for cracks, fraying, or glazing.
- Check the top corners, belt sidewalls, top surfaces, bottom corners, and bottom surfaces for strange wear patterns.
- Watch out for sidewall burning or hardening undercard cracking, as these show belt damage.
- Pay attention to unusual noises like rubbing, chirping, squealing, slapping, or grinding, as these sounds suggest problems with the belt.
People Also Ask
Here are some questions and their answers about engine temperature spikes and then return to normal.
Does idling increase engine temp?
Idling can cause an increase in engine temperature because the engine continues to generate heat even when not actively moving. However, modern engines are designed to handle idling within normal operating temperatures. Excessive idling, though, can contribute to long-term wear and fuel consumption.
Do I know if my coolant is circulating?
If you want to ascertain if your coolant is circulating properly, check the lower and upper radiator hoses. You can check the temperature of these hoses with an infrared thermometer. The upper hose should be hotter, around 190° to 200°F. Meanwhile, the lower hose should be colder than the upper, around 60°F.
Final Words
Engine temperature spikes can result from various issues, such as low coolant levels, thermostat problems, radiator malfunctions, and more. To prevent further engine damage, it’s crucial to diagnose and rectify these problems. Regular maintenance and inspections play a preventive role, with spike testing aiding in issue identification.
Ignoring these concerns can lead to costly repairs or total engine failure. Therefore, it’s advisable to check coolant levels and inspect other components. Solutions may involve adding coolant, replacing parts, or adjusting engine timing to ensure smooth vehicle performance.
