There could be several reasons why your car is making noise when you start it, but the noise goes away after a few minutes. Here are a few possible explanations:
Belt or pulley issues: The noise could be due to a loose or worn-out belt or pulley. When the engine starts, the belt may slip or make a squealing sound until it warms up and gains proper tension.
Engine oil viscosity: If the engine oil is too thick when the car is started, it may not lubricate the engine components effectively. As the oil warms up, it becomes thinner and flows more smoothly, reducing friction and eliminating the noise.
Hydraulic lifter noise: Hydraulic lifters are responsible for maintaining proper valve clearances in the engine. Sometimes, they can become noisy if there's an issue with oil flow or if they need adjustment. Once the engine oil circulates and reaches the lifters, the noise may subside.
Exhaust system components: Problems with exhaust system components, such as a loose heat shield or a damaged muffler, can create noise upon startup. As the components heat up and expand, they may align or settle, reducing the noise.
Cold weather effects: Cold temperatures can cause various components of your car to contract, leading to noise upon startup. As the engine and surrounding parts warm up, the noise may diminish.
It's important to note that diagnosing the exact cause of the noise without inspecting the car in person can be challenging. If the noise persists or you notice other issues with your vehicle, it's recommended to have a qualified mechanic examine it to provide an accurate diagnosis and necessary repairs.