What does cold start mean for a car?

[Ben]

Cold start of a car refers to starting the engine when the coolant temperature is low. The reasons for car cold start shaking include: 1. Dirty throttle or excessive carbon deposits in the fuel injector; 2. Fuel quality issues; 3. Failure of the coolant temperature sensor; 4. Unstable oil pressure; 5. Aging engine mounts; 6. Faulty spark plugs or ignition coils. The methods to address car cold start shaking are: 1. Read fault codes or data streams to rule out sensor failures; 2. Check if the exhaust gas valve has any issues; 3. Inspect spark plugs, high-voltage wires, ignition coils, fuel injectors, timing marks, fuel pump pressure, and cylinder pressure; 4. Check for problems with the idle speed motor, and clean the throttle and idle speed motor.

[ZacharyAnn]

When I first started driving, I didn't understand what cold start meant either. Later, I figured out it refers to starting the engine when the car is completely cold. Especially on winter mornings, after the car has been parked overnight, the engine metal is ice-cold. At this point, the engine oil's fluidity becomes very poor, settling at the bottom of the oil pan, leaving the piston and cylinder walls in a state of dry friction. That's why the engine sounds particularly loud and shakes violently during startup—it's due to the lack of lubrication between parts. A mechanic once told me that cold start wear accounts for 70% of total engine wear. Later, I noticed on the car's computer that during cold idle, the RPM automatically revs up to around 1200 to warm up quickly. Now, I make it a habit to wait until the idle stabilizes at 800 RPM before driving off, giving the metal parts time to adjust to thermal expansion.

[BlakelyLynn]

I used to think starting a car was as simple as turning the key, but later I learned there's a lot of science behind cold starts. The term 'cold' here doesn't refer to air conditioning, but rather the engine being below its normal operating temperature. Typically, ignition below 80°C counts as a cold start. At this point, the engine oil's high viscosity causes delayed oil filling in hydraulic lifters, resulting in clattering noises from the valve train. What's worse, the catalytic converter hasn't warmed up yet, emitting two to three times more harmful substances than usual. That's why I specifically switched to 0W-grade oil for better low-temperature fluidity. But modern cars are smarter now – mine automatically enriches the fuel mixture during startup, and once the temperature gauge starts moving, it's ready for smooth driving.

[CamilleFitz]

The term 'cold start' sounds technical, but it simply means starting the engine when the car has cooled down. You know, like when you park outside in winter and find the windshield frosted over - that's when starting the engine makes it rattle like it's about to fall apart. The main reason is that the engine oil hasn't circulated yet, leaving metal components inside insufficiently lubricated. Some older cars even emit blue smoke from the exhaust pipe, which are all signs of abnormal cold engine operation. That's why I never stomp on the accelerator when the engine is cold - I always let it idle for 20-30 seconds first. If you notice difficulty starting, it's probably a weak battery that needs immediate inspection.