What Causes the Metallic Screeching Sound During Cold Start of a Prado?
4 Answers
The causes of metallic screeching sound during cold start of a Prado include: 1. Loose accessory belt, leading to increased load and belt noise when accelerating; 2. Carbon buildup in the throttle body, causing poor throttle response and dirty idle control valve/throttle plate; 3. Carbon-oil mixture accumulation in the engine intake tract, resulting in buzzing noise during sudden acceleration. Solutions: 1. Inspect generator/compressor/power steering pump belts for looseness and replace/tighten if needed; 2. Check throttle body contamination for cleaning and recalibration; 3. Clean intake tract oil-carbon mixture using specialized intake cleaner; 4. Inspect throttle pedal spring for looseness/fatigue and replace if necessary.
Over the years of driving my Prado, I've encountered the metallic screeching sound during cold starts a few times. The most common issue is belt slippage—when the alternator or AC belt ages, its elasticity deteriorates, causing it to contract in cold temperatures and squeal. That's exactly what happened to my car last time. A quick check involves inspecting the belt surface for cracks or looseness. Additionally, a worn tensioner pulley bearing can produce similar screeching noises; once it loosens up, it becomes unbearably loud during startup. I've also experienced a failing water pump bearing, where insufficient lubrication when the engine is cold makes the metal grinding noise particularly noticeable. My advice? Don’t delay—first, check the belt tension yourself. If something feels off, get a professional mechanic to inspect it. Ignoring such minor issues for too long can lead to serious damage to the chain system. Paying attention to these components during regular maintenance can save you a lot of hassle.
The metallic screeching noise from my Prado during cold starts is really nerve-wracking. The sound most likely comes from the timing chain area, where the tensioner doesn't work well under low oil pressure, causing the chain to rub and produce that harsh noise. Additionally, if the starter gear or flywheel ring gear is worn and doesn't mesh properly, it can also create that kind of noise. I recommend not taking random actions to avoid accidental damage to the vehicle. Going directly to a 4S shop or a reliable repair shop for diagnosis is the safest approach. They can easily check the oil pressure or wheel bearing conditions with instruments and resolve the issue. Ignoring it could lead to high risks of internal engine damage, causing repair costs to skyrocket. Driving safety is no small matter; any unusual noise should be investigated immediately.
Hey, the metallic noise during cold starts on the Prado is quite annoying, most likely an issue with the VVT-i system. Low temperatures increase oil viscosity, leading to insufficient lubrication and causing the valve train to squeak. I've helped a friend fix something similar—just replacing the belt or checking the tensioner did the trick. If the chain tensioner gets stuck, it makes a loud pulling noise during cold starts. Try tightening the belt first; if the situation improves, it's a minor issue. Regular application of good lubricant can prevent bigger problems. Don't wait for the noise to get worse; simple maintenance can avoid major disasters.
