What is the abnormal noise of the engine after the Toyota cold car starts?

1. Hydraulic tappet: Due to low oil pressure or wear of the hydraulic tappet itself, air enters the hydraulic tappet, resulting in abnormal sound.

2. Valve clearance: The valve rocker arm is worn, resulting in excessive valve clearance.

3. Dirty throttle: The throttle is too dirty due to the continuous accumulation of sludge and carbon.

4. Working sound of carbon canister solenoid valve: This is a normal sound and can be used continuously.

5. Three-way catalytic converter: there is a "click" sound within half a minute after the cold car starts, and then there is no sound. This is generally the sound made by the expansion of the three-way catalyst after heating.

6. Timing part: When the cold car is started, there is a relatively large abnormal noise, generally, the timing belt or chain is worn, stretched and loosened, and the chain tensioner loses its tensioning function, resulting in this abnormal noise.

7. Air conditioning belt rubbing sound: If there is noise when the air conditioner is turned on, it may be caused by air conditioning belt rubbing.

8. The fuel tank exhaust valve is not working properly.

9. The fluid in the reflux pump has influence.

10. The internal part of the fuel filter is blocked. There will be abnormal noise and loud noise when the engine is started in a cold car, because the oil can't reach the working temperature, so there will be this problem. In addition, the cold weather will affect the battery voltage, making it difficult to start. If the throttle carbon deposit cannot be solved, check whether the battery voltage is abnormal.