Why do I hear a knocking sound when I start my car?

If you start up your car and hear knocking noises, this usually means the fuel of the car was not ignited properly. This could be due to low-quality fuel, bad spark plugs, or another reason above. But for many high compression or high performance vehicles, 91 or even 93 octane fuel is necessary.

Why does my car make a noise when it’s cold?

Cold weather can exacerbate underlying car problems, so you may begin to hear squeaks, squeals and other funny noises you haven’t heard before. These noises may be caused by the engine belt, the serpentine belt, the air conditioning compressor or a power steering pump.

How do you fix a knocking noise in your engine?

How to Fix Engine Knocking

1. The first step in trying to fix engine knocking is to upgrade to gasoline with a higher octane rating.
2. Give your engine a tune-up that includes new spark plugs and wires.
3. Regularly change the oil in your vehicle and monitor for a low oil level.

Why does my car sound loud when idling?

Loud idling is usually caused by issues with cylinder compression. When there are problems with cylinder compression, you get an uneven fuel-air ratio. As a result, combustion becomes unusual. Having higher pressure inside the cylinder will result in loud idling noise.

Is it bad to drive on cold engine?

The best way to bring your engine up to operating temperature is to gently drive your car. So the longer you let a cold engine idle, the more fuel you waste and the more you increase the chance of fuel residue build up. Fuel residue build up can lead to poor engine performance and a reduction in mileage.

Why do engine make knocking noise when cold started?

My Tl make a loud knocking sound when I first start it up in the morning or after being parked for at least 6 hours. (summer or winter) After the engine is warm the noise stops and the engine runs like when I first bought the car 4 years ago. Do anyone know what’s causing that to happen?

How long does engine knocking last after cold start?

Knocking is still present but much quieter. It is possible this has been going on longer than the recent oil change, as I can’t hear it in the car. Lasts maybe 30 seconds after cold start (haven’t tried warm start to know for sure). It is louder on the bottom of the engine compared to the top. Attached audio (from under engine) as requested.

What should you do if your car is knocking on cold start?

Smell the dipstick. If it has the odor of gasoline it would be advisable to not start the engine until it has been drained and refilled with the proper oil and the source of the contamination found and repaired.

Where does the knocking come from on a cold start?

I noticed a knocking coming from the engine (closer to bottom of engine than top) on a cold start. It sounds like a rock being knocked against a hard surface. I can only hear the knocking if I am outside of the car, if I am in the car I can’t hear it at all. The knocking lasts for maybe 20-30 seconds.