You have started up your car and heard a knocking sound from the engine. Sadly, you do not know why the engine knock on startup then goes away and how to stop this awkward noise. Don’t worry. This article is created for you.
We will show you some main factors leading to this problem and some methods to avoid knocking sound in the future.
How To Do If Your Car Makes Noise When Starting Then Goes Away?
Sometimes, you may hear a loud engine noise on startup, lasting for some seconds or a minute. This phenomenon is quite normal in almost all types of cars, and fortunately, you can stop this awkward situation with two basic steps.
Firstly, you have to heat the engine for a while. This method is really useful and effective.
The heating up process can ensure inside components such as the crank and oil are warm enough to perform normally.
The next action you have to take is to bring your vehicle to a professional mechanic store for a checkup. Various factors can be the causes of this buzzing sound after starting car.
Some of them are easy to detect, while there are some underlying issues that only professionals can diagnose and fix.
After identifying and fixing problems, you should do some maintenance process to avoid similar problems which may arise.
Why Does Engine Knock On Startup Then Goes Away? How To Fix It?
Below are five factors that make the engine rattle on startup then goes away. Although you are not a professional, you can easily detect these causes: piston slap, sticky valve lifter, worn engine, worn bearing wear, and oil-drain back.
Piston Slap
Before diving deep into the phenomenon of piston slap, you should understand what a piston is.
Basically, the piston is a thick metal disk that fits with the inside cylinder wall. It is connected to a rod that links them to the crankshaft.
Once the piston goes upward and downward, it forces the crankshaft to move along with it. The rotation created in this procedure will be transferred to your wheels throughout a driveshaft.
When you start or accelerate the engine, you may hear a “piston slap” engine noise. A piston moving up and down during rotation results in the knocking sound.
Especially in cold weather, the piston tends to move more.
The most common causes of piston slap are old pistons or worn-out spark plugs. However, once you heat the engine for a few minutes, there is little chance of this problem.
Sticky Valve Lifter
Another factor leading to a single knock when starting car is sticky valve lifters. Numerous factors create a sticky valve lifter. But, almost all of them are oil-related problems.
For example, the kind of oil you use, the type of oil filter, the condition of oil pumping, mileage, and even any components involving moving them.
If the engine oil doesn’t reach the inside parts correctly, it can cause a sticky lifter and poor engine seals and lead to piston slap or even dodge charger clicking noise when starting.
In this condition, the best solution is to change your engine oil at regular intervals and get your engine usually checked to avoid probable issues.
Worn Engine & Components
Common worn engine components that cause engine knocking noise during startup are water pumps, power steering pumps, exhaust manifold, and alternators.
These noises are considered normal working conditions, and your car will perform appropriately once a specific part fails.
