What Causes the Sizzling Sound When Starting a Cold Engine?
2 Answers
The sizzling sound when starting a cold engine is caused by the valves. After the car has been parked for an extended period, the engine oil flows back to the oil pan, leaving the top of the engine, specifically the valve chamber, with insufficient oil. Since the valves lack the sealing and lubrication provided by the oil, this can result in the sizzling noise. Additionally, sometimes the car's belt may be loose, leading to a similar sound. In such cases, it is advisable to visit a repair shop to have the belt checked and tightened appropriately to see if the issue resolves. Regular maintenance of the belt is essential, ensuring it is neither too loose nor too tight. You can manually check the belt's tension by pulling on it; if it feels excessively loose or tight, it's best to have it inspected by a professional. Furthermore, if the sizzling sound occurs when applying the brakes while driving, it indicates that the brake pads have worn down to their limit and are now grinding against the brake discs. In this situation, immediate inspection and repair at a service center are necessary to identify the exact cause of the noise and avoid further driving under such conditions.
My car also had the issue of a squealing noise during cold starts last year, and it took a long chat with an experienced mechanic to figure it out. The most common cause is wear on the starter motor gear, which can produce a metal grinding sound if the gears don’t mesh properly during ignition. Another possibility is aging or loose alternator belts—when cold, the belts harden and slip, creating a friction noise similar to a rubber band about to snap. If the battery voltage is insufficient, the starter motor may struggle to turn, also causing unusual sounds. In my case, replacing the battery eliminated the noise, but I still recommend getting the starting current tested with professional equipment at a repair shop. Don’t ignore cold-start noises; failing to address them promptly could lead to complete starter motor failure.
