What Causes the Boiling Water Sound When Starting the Engine?
3 Answers
Because the engine experiences a significant jolt at the moment of starting, impact sounds may occur in areas with excessively small gaps. Adjusting the deformed gaps can eliminate these abnormal noises. The boiling water sound from the engine is considered an abnormal noise and requires repair. Engine abnormal noises can generally be categorized into: Abnormal noises during cold starts, abnormal noises during rapid acceleration, and abnormal noises during idle. Abnormal noises caused by aging or loosening of the engine mounts. Engine mounts, also known as rubber mounts or engine brackets, are typically installed between the engine and the vehicle body, connecting the two and securing the engine in place. Their most important function is to provide cushioning and vibration damping. Once the engine mounts age or become loose, engine vibrations will intensify. During maintenance, the following aspects should be noted: If components such as the fuel filter, oil filter, air filter, hydraulic oil filter, and various filter screens become excessively dirty, the filtering efficiency will decrease, allowing more impurities to enter the oil passages and cylinders, accelerating wear on mechanical parts and increasing the likelihood of faults. Severe clogging can also prevent the vehicle from operating normally. Excessive piston temperatures in the engine can lead to overheating, melting, and cylinder seizure. Overheating of rubber seals, V-belts, tires, and other components can cause premature aging, reduced performance, and shortened lifespan. Overheating of coils in electrical equipment such as starters, generators, and regulators can easily lead to burnout and scrapping. Vehicle bearings should be kept at an appropriate temperature; overheating will cause the lubricant to deteriorate quickly, ultimately leading to bearing failure and vehicle damage.
As an old hand who's been driving for decades, I've encountered that gurgling sound like boiling water when starting the engine a few times. Experience tells me it's mostly the cooling system acting up. It could be the water pump wearing out and not spinning fast enough, causing poor coolant flow and localized boiling; or the coolant level being too low, making bubbles gurgle as the engine temperature rises; sometimes it's air bubbles trapped in the lines. I remember my car did this last year, turned out the water pump impeller was cracked - spent some money on a new one and it went quiet. You should quickly check the coolant reservoir when the engine's cold, see if the level's at the normal mark - if low, top it up with the proper brand. But for a permanent fix, best take it to a professional shop to check the water pump, thermostat and radiator, to avoid engine overheating and major repairs. Never mess with it when hot, to prevent burns or bursts.
As a car enthusiast who frequently tinkers with engines, this boiling water sound is quite common. It usually stems from water pump issues, such as aging bearings causing unstable rotation and noise; or a stuck thermostat failing to open, causing the coolant to boil as the temperature soars. It could also be due to air bubbles entering the cooling system or minor leaks. After starting the engine, monitor the temperature gauge. If it rises rapidly, shut off the engine to prevent damage. For a quick check: when the engine is cold, open the cap and feel the radiator hose for abnormal vibrations, and listen for the noise source to pinpoint the issue. Regular maintenance includes topping up fluids and periodically flushing the system to prevent corrosion and blockages. If the noise persists, use professional equipment to test for pressure leaks or replace components. Don't ignore it to avoid turning a minor issue into a major one.
