Why Is Coolant Leaking From My Cars When It’s Not Running?
While you may think that the coolant is off the car while you drive, but that’s not the case. When the engine runs, the coolant circulates through the system, making it look less visible. So, if the car doesn’t drive, what causes the coolant and leaks? In this guide you will see why the coolant appears to have the engine turned off. I will also show you some simple ways to fix the problems.
Causes of Coolant Leak While Car is Running
Coolant leaks when the car is not running can be caused by damaged hoses, a bad radiator cap, a bad radiator, or a defective water pump. Itâs also possible that there is a bad heater core or a blown head gasket. A bad intake manifold gasket could also be to blame.
Here is some more detailed information on what could cause a coolant leak when the car is running.
1. Bad Heater Core
Hot coolant gets pumped into the engine through the systemâs heater core. The heat that is generated from the system gets blown into the vehicle through the HVAC vents when you activate the heater.
If the heater core is bad, you will notice trouble getting heat into the system. You might also see leakage under the vehicle around the passenger or driver seat area.
2. Damaged Hoses
A broken hose can also cause a leak when the engine is running or not. As the motor runs, the pressure of the system can either increase the leak or decrease it, depending on where the hole is.
Either way, hoses can become brittle and worn over time, which is why they should be regularly inspected. The heat and constant pressure can increase the wear if left unchecked.
3. Bad Radiator Cap or Radiator
The radiator cap is needed to keep the coolant in the system where it belongs. It also helps to regulate the pressure in the radiator.
If the cap is damaged, coolant can leak out, leading to lower levels in the radiator. Additionally, the coolant reservoir could overflow when you run the engine because of the higher pressure in the hoses. The radiator could also be cracked or damaged from any external damages like corrosion or stones when traveling at high speeds.
4. Blown Head Gasket
If the coolant has started leaking into the engine oil or combustion chamber, a blown head gasket is the likely cause. The head gasket is responsible for keeping the oil and coolant separated from one another.
As coolant leaks into the system, itâs no longer able to keep the engine cool. This problem occurs when the engine is running and when itâs off, but running the engine is more dangerous, since the motor will start overheating. A bad head gasket can also cause external coolant leakage and you will see if coolant leaks out between the engine block and the head.
5. Defective Water Pump
If the water pump becomes damaged, you might notice a huge coolant leak. The water pumpâs job is to push the coolant through the hoses smoothly. As the water pump starts to fail, the coolant can no longer flow the way it should. This is yet another issue that can cause problems with the engine on and off.
6. Bad Intake Manifold Gasket
The intake manifold gasket is found at the spot where the manifold connects to the engine. If coolant is leaking below the vehicle, it could be caused by a bad gasket. As with any of the issues, the sooner this is repaired, the better off you are. Otherwise, it could create large problems when the engine is running.
Areas to Examine for Coolant Leak
1. Radiator/Cap
The first place to look for a leak is around the radiator. You might need to clean off the radiator of leaves, dirt and debris to see where the coolant is coming from. You should also examine the radiator cap to see if it is damaged. It should be securely attached to the radiator to avoid leakage and other consequences.
2. Hoses
There are hoses throughout the system that should be examined. If there is a torn hose, the coolant should be dripping from its surface. Depending on where the hole is, the leak may only occur when the engine is running or off, based on where the coolant is at the time. You also want to look for cracks in the hose surface. Even if there isnât a hole yet, coolant could easily be seeping through the crack.
3. Under Vehicle
Get underneath the vehicle and take a good look for leaking coolant. Depending on what kind you use, the liquid will be blue, red, or green.
By determining where the leak is coming from, you will have a better idea of what part might have failed. If you have driven with a coolant leak, it might have blown onto other parts. Wash down the undercarriage and inspect it again for a better idea of where the leak is coming from.
4. Heater Core
Take a peek at the floorboards under the passenger seat of your vehicle. If you notice coolant stains, the problem could be the heater core. When the heater core is damaged, it can leak fluid under the car on that side. It will also cause lower levels, which could lead to the engine overheating.
