Hearing unusual sounds coming from your car can be unsettling as it could indicate a problem with the various vehicle’s moving parts. However, when noises show up when turning off the engine, the two occasions might be related.
Grinding noises after turning off the vehicle can be caused by a simple thing, like a condensing part as the engine loses its heat. However, other reasons may be behind the sounds, including a loose or damaged car part. As a helpful assistant, I recommend you do further diagnostics to determine the cause.
The article discusses the grinding noises some drivers hear after turning off their vehicles. It also covers various reasons for the noises you may be hearing.
What Causes Grinding Noise When Turning Engine Off?
When the car makes this noise only after its engine has been turned off, the two scenarios are related. Unlike a hissing sound from engine after turning off, this noise points out a more mechanical issue.
Determining what is causing the grinding noise is usually tiring since the noises may appear irregularly. Also, like most car issues, the sound may fail to show up when a mechanic is around, making it hard to diagnose them.
Nonetheless, I find some of these causes behind the noises easy to diagnose and fix once you know what they are. The following list contains some of the reasons the car has grinding noises.
1. Low Transmission Fluid
When I hear grinding noises in my car, the transmission is one of the parts I check. The car’s transmission is one of the car parts with multiple moving gears capable of making grinding noises.
One of the reasons the transmission makes grinding noises is due to low transmission fluid. When the transmission fluid is low, the gears grind on each other as they run. Since the engine is usually loud, you may only hear grinding noises when it turns off.
Diagnosis
To be certain that the transmission is causing the grinding noises, observe the following factors;
- The vehicle has problems shifting.
- Your car has over 50,000 miles from the last transmission change.
- No noises when the transmission is in neutral gear or with the clutch pedal pressed in.
- Dipstick shows that the transmission fluid is low.
Solutions
Usually, the noises are due to low transmission fluid, and refilling usually solves the problem. Follow the steps below to refill your transmission fluid.
- Step 1. Start the car and set the emergency brakes.
- Step 2. Place the funnel in the transmission hole where the dipstick usually sits.
- Step 3. Add a compatible fluid a little at a time while checking its level with the dipstick.
- Step 4. Replace the dipstick once the fluid is within the required range.
You can hire a mechanic to diagnose and refill your transmission. The service can cost anywhere between $100 and $300, depending on your car.
2. Steering Wheel Lock
Most vehicles have a steering wheel lock system, which is a theft-deterrent feature. In most vehicles, this feature activates as soon as the engine turns off, especially if set to automatic.
After turning off the engine, the steering wheel may be activated automatically if set and create the grinding sound.
Diagnosis
To confirm that the steering wheel is causing the grinding noises, check for the following things.
- The steering does not turn in any direction after the sound.
- In some vehicles, the key must be off to activate.
- Also, in some vehicles, the steering must be wiggled slightly to activate.
Solutions
Most of the time, avoiding the steering lock from activating is as simple as avoiding touching the steering lock. Also, pushing the key in the ignition, wiggling the steering wheel, and turning it on disengages the lock.
3. Throttle Body
Various engines, like the VK50VE engine, are equipped with an electronic throttle control. This feature controls the amount of air the engine gets based on your press on the pedal.
When turning the engine off, the server closes the throttle intake manifold, which makes a noise. Most vehicles with electronic throttle bodies have more than two intake manifolds that can close at different times. These differences can create more noise resembling that of grinding.
Diagnosis
Observe the following things to confirm the throttle body is causing the noises.
- Your car has an electronic throttle.
- The noises happen every time you turn off the vehicle.
Solution
The sound from the throttle body is normal, so there’s no reason to be concerned.
4. Air in The Cooling System
The vehicle’s cooling system sometimes leaks due to pressure build-up or worn-out seals. When the coolant leaks out, its space is replaced by air from the environment.
The coolant stops running through the system when the vehicle engine stops running. At this time, the air in the coolant gurgles as it tries to rise since it’s less dense than the coolant. These gurgling noises can sound like grinding noises, especially when in various parts at once.
Diagnosis
To confirm the sounds may be caused by air in the coolant, observe for various things, including;
- Reduced cooling on the vehicle
- Evidence of a coolant leak
- The sweet-like smell from the car as the AC runs
Solutions
Air in the cooling system means a low coolant level, and the solution is to refill it. However, before adding the coolant, get a professional to check for leaks and fix them. Buy your preferred type of coolant and follow the steps below to refill.
- Step 1. Park the vehicle on level ground and let the engine cool.
- Step 2. Remove the coolant reservoir cap for the reservoir-type system. For the radiator system, remove the radiator cap and insert a funnel.
- Step 3. Add coolant up to the cold fill line.
- Step 4. Start the engine and continue adding the coolant to the reservoir refill line.
- Step 5. Replace the reservoir or radiator cap.
- Step 6. Observe the coolant level for the next few days.
Bleeding the cooling system costs between $100 and $200, depending on the vehicle.
5. Loose Car Parts
As the vehicle ages, some parts become loose and grind on each other as the engine vibrates. Most of the time, the loud engine noise hinders these grinding noises, and they become more audible as the engine turns off.
Diagnosis
To confirm that a loose part is causing the grinding noise, observe the following things;
- Check for a loose part in the vehicle or have someone listen as the engine runs.
- If you listen more keenly, you may hear a squeaking noise from the engine when idle.
Solutions
The solution to a loose car part is to get the loose part tightened or replaced. Most of these parts require a professional to change and once you have figured out the part you can hire one.
Diagnosing and replacing the loose part can cost anywhere between $100 and $400, depending on the part.
6. Contraction
A car engine works at high temperatures, usually above 195° (91°C.) Around this temperature, most of its parts and the surrounding parts have expanded. When the engine turns off, these parts begin to contract and may result in the grinding noises you are hearing.
These sounds are normal, and there’s nothing to be concerned about. However, ensure you diagnose the vehicle further in case there’s a faulty part.
Concluding Remarks
If you hear grinding noises when you turn off your vehicle’s engine, the most probable cause is the transmission. However, it’s necessary to diagnose your vehicle further to determine the actual cause.
In most cases, the reasons might not be due to a problem but rather a natural occurrence. You have the option to hire a mechanic to diagnose your car or follow the steps outlined above to do it yourself.
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