How do you know which side to fix?

when i turn my car on it makes a very loud grinding noise

My car has 134000 miles.
My car has a manual transmission.

Experienced mechanics share their insights in answering this question :
Hi there – beside eyes, ears and a stethoscope (yes, really), our mechanics are trained to understand how, and from where, sound and vibration originate when there is a problem. I recommend a [ performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

If you hear grinding noises when driving and braking, try braking a little harder. If the sound gets worse, then you may have worn out brake pads. Stop the vehicle and take a look at your brake pads. If you are not sure where to look, consult your owner`s manual.
If you hear this grinding noise both while you`re driving and idling, it`s possible that worn-out bearings are to blame. If the grinding noise comes when you shift, it`s likely due to a worn clutch. Grinding when you turn a corner could be due to a CV joint that needs to be replaced or another suspension issue.
A common cause of grinding noises under your car are failing wheel or hub bearings. Wheel bearings allow the wheel and tire to rotate and are designed for low friction, while hub assemblies have an additional responsibility of securing the wheel and tire to the vehicle.
Most of the time, if you hear scraping and grinding, it can be attributed to one of two main issues: Worn-out brake linings. Worn-out wheel/hub bearings.
You`ll receive a warning squeal as the pads wear away–right before the metal backing plate starts rubbing against the brake disc. This causes a very loud grinding noise (metal on metal) whenever you put your foot on the brake. If it gets to this stage, your car is now dangerous to drive.
Driving with grinding brakes is simply not safe. Brakes are a critical component of safe driving and should not be overlooked. If your brakes start to fail: Don`t drive any further.
When your engine oil is running low, your engine`s components stop receiving the lubrication they need to function properly. Once this happens, you may start to hear clunking, knocking, ticking, or grinding noises coming from your vehicle`s engine.
Your Alternator Might Be Wearing Out

When your alternator is starting to wear out it will often make a grinding noise. This is because modern alternators have a decoupler pulley system designed to help you save on fuel, but can make a grinding noise when they are not working properly.

Grinding Sounds When Turning the Wheel

Audible noises in your vehicle that don`t sound normal indicate a problem. The same goes for the steering wheel. If you turn it and hear popping or grinding, it`s likely coming from the steering column.

Most likely, if it is true grinding that you hear, the problem is related to the starter. Causes include the starter not lining up correctly with the ring gear on the flywheel, missing or damaged gear teeth, or a faulty solenoid. Replacing the starter is most often the right solution.
Metal on metal contact between one or more parts of your vehicle`s suspension and/or steering systems is likely to blame. Causes may range from worn suspension bushings to broken coil springs to badly worn ball-joints, and more.
To avoid this be sure to press down fully on the clutch pedal when changing gears and remember to shift smoothly and softly. Grinding your gears too much or trying to force a gear change could cause long-term damage to your car.
You can damage the brake rotors and calipers.

When you brake, the brake pads squeeze the rotor to stop your car. However, when the pads are excessively worn, exposed metal on the pads grinds against the rotors every time you brake, producing a grinding noise and likely damaging the rotors.

If your brakes emit a sharp grinding sound while braking, it`s likely that the brake disc and the caliper are rubbing together. The sound is usually heard when you stop your car, but you may also feel the brake pedal rumble as you step on it.
The metal-on-metal grinding noise you hear is the steel part of the brake pad grinding against the brake rotor, and it`s not good. You need to get a brake pad replacement immediate when they are shot before they also destroy your rotors or brake calipers, which can be a very expensive repair.
Loud squeaking or squealing noise while accelerating could mean there`s a problem with your engine belt. It could mean the belt`s loose or worn. Or it could mean that one of the belt`s pulleys is starting to fail. Loud rumbling noise when accelerating might suggest there`s a problem with your exhaust system.
A squeaking or squealing sound when you`re accelerating or cruising can mean there`s a problem with a drive belt on the engine. You should get this checked as soon as possible. Slapping noises when accelerating usually mean a tyre is flat or under-inflated.
One of the top indicators of engine damage due to low oil is unusual sounds. If you hear grinding, clunking, or knocking noises from your engine, your engine may run without enough lubrication, leading to metal-on-metal contact.
Batteries. When batteries run low on power, they`ll rapidly alternate between the on and off positions instead of staying on, which could cause something that sounds like grinding. In general, you should replace your battery every 3-5 years.
If you notice your car making a grinding sound when it accelerates, your issue is likely to do with your transmission, a problem with your differential, a bad wheel bearing, a damaged CV joint, or a worn engine/motor mount.
Q: Is it safe to drive with a bad wheel bearing? A: No. It can, in fact, be very dangerous to drive if one of your bearings is worn out, especially since it may cause the wheel to stop while driving. Additionally, a damaged wheel bearing puts a lot of stress on the hub, the CV joint, and the transmission itself.
If you hear grinding noises when stopping or slowing down, your brake pads are most likely the issue. Remember, over time your brake pads lose their thickness and begin to make squealing noises known as “brake scrubbing.” As your pads wear down further, you`ll hear a grinding noise instead.
Q: Is it safe to drive with a bad wheel bearing? A: No. It can, in fact, be very dangerous to drive if one of your bearings is worn out, especially since it may cause the wheel to stop while driving. Additionally, a damaged wheel bearing puts a lot of stress on the hub, the CV joint, and the transmission itself.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Driver side door lock button not working, and passenger side sliding door makes a buzzing noise
ANSWER : Hi there. These door issues are common on this vehicle. Most of the time the main issue is the master door lock switch on the driver door. It sounds like you already replaced that. As for the sliding door problem, most of the time, this is a failure within the door module or it can be a connection issue.

I typically take the door apart and check the connections on the module and inside of the door just to make sure that there is nothing apparent in there. If the connections and the wiring are fine, then I use a scan tool to check the module to see what the inputs and outputs are doing. If you need to have this looked at, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your door problem and recommend a repair.

How do I know I have two resonators? Can I have two mufflers in each side with one resonator? Which side is most important? Thank You.
ANSWER : You may have a single small resonator in the middle of the car that splits to the two mufflers. One on each side with single or dual tip outlets. The two mufflers are equal to each other to exit the exhaust flow. For more concrete advice, I’d recommend having an expert technician check out your specific muffler situation in person. A technician from YourMechanic can come to your home or office inspect your exhaust system and assist with any repairs that are needed.

Driver Side Inner & Outer Tie Rods and driver side strut being bent.
ANSWER : From what you’ve described, the damage was most likely caused from hitting a pot hole. If the damage was from a pot hole on the right side, in some cases it’s possible for the force to transfer over and damage the left side as well. If you’d like a second opinion on this, consider YourMechanic, as a certified technician can come to your home to diagnose your car’s suspension system and confirm these suspicions.

2012 fusion ddamage front pass side trunk shifted to the drivers side. Is this possible
ANSWER : Request that a professional alignment shop use a tram to carefully and completely measure the unibody and compare all such measurements against the data set out in detail in your vehicle’s Factory Service Manual. Using that strategy it will be easy to conclusively and authoritatively determine if the unibody is damaged. If the unibody was damaged in the collision it will have to be repaired, if cost effective, or obviously the insurance company will have to make you whole on your claim for damage. If you have any further concerns, do not hesitate to contact YourMechanic as we are always here to help you.

How to check which (valve/head)gasket is not working& what is the price to fix head gasket ?
ANSWER : The problems you describe (leaking radiator, overheating) often lead to a "blown" or leaking head gasket. For your vehicle, there is only 1 head gasket, which would need to be replaced. This is in addition to any failure of the radiator or other cooling system components.

I recommend having a YourMechanic mobile, professional mechanic come to your location and perform a car is overheating inspection. This inspection will identify failed cooling system components (radiator, head gasket issues) and recommend/quote needed repairs.

Is there grease in the left side front driver side wheel bearing
ANSWER : The wheel bearings on the front of your car are within unitized hub assemblies and thus the grease that is placed within when the hub is manufactured is permanently sealed inside. It will not leak out. If the bearing has failed that is typically due to overtightening of the axle nut when the vehicle is re-assembled during the repair. The nut that holds the CV axle to the hub can ONLY be tightened with a calibrated torque wrench and the nut has to be tightened only to exact value published in the Factory Service Manual. Shops and amateurs will sometimes use an air tool or an ordinary wrench, contrary to the explicit instructions, and the consequence is the axle nut is overtightened and the bearing is guaranteed to fail prematurely. The other common cause of premature bearing failure is the use of cheap aftermarket bearings (or hub assemblies). If you use the OEM (dealer supplied) bearing or a recognizable, reputable vendor such as SKF you will be better off. The grease you are seeing is from another source and that is likely to be the CV outer joint. You can check to see if the outer CV boot is torn or damaged. If so, the grease has come out and CV joint failure is not far off. To get the bearing inspected, and replaced if failed, please request hub assembly inspection/replacement. To obtain service on the CV joint, please request CV joint inspection/axle replacement. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Front driver side tire moves side to side when jacked up
ANSWER : If you can move the tire in and out when on a jack then you may have a few different possible problems. The inner or outer tie rod ends may be worn. Your steering gear may also have worn bushings. I would recommend moving tire back and forth while holding onto the tie rod ends to see if looseness is felt and replace any loose components. An alignment will need to be done after repairs.

Power mirror on passenger side will not retain it’s setting driver side works perfect.
ANSWER : A technician with an advanced scan tool can verify the issue. The mirror system is complex and involves many modules. The Body Control Module is a possible cause, but it’s doubtful; replacement requires reprogramming, which requires special equipment. I would check the driver’s and passenger’s door modules; toggle or move the switch on the driver’s side to see if it causes the problem, and ensure that the mirror glass itself is not loose on the passenger’s side mirror assembly.

Without diagnosing the problem with advanced equipment, the issue is hard to diagnose. A qualified YourMechanic technician can show up to the location of your vehicle with a scan tool to inspect and diagnose your power mirror issue.