Should You Use P Gear or N Gear for Warming Up the Car?

[OLayla]

If the intended direction is reverse, use P gear for warming up the car, as no gear change is needed from warming up to driving; if the direction is forward, you can use either N gear or P gear. Below are detailed introductions to car gears: 1. P gear is the parking gear: When the gear lever is in P gear, the transmission is in neutral, but the output shaft is mechanically locked. The car will remain stationary even without pressing the brake, typically used for long-term parking. When engaging P gear, the car must be completely stationary. Do not engage P gear before the car has fully stopped, and always apply the handbrake. On slopes, engage the handbrake before shifting to P gear. 2. R gear is the reverse gear: When the gear lever is in R gear, the transmission output shaft rotates opposite to the engine's direction, allowing the car to move backward. The car must be completely stationary before engaging R gear. 3. N gear is neutral: When the gear lever is in N gear, the transmission gears are idling, the clutch is disengaged, and the transmission load is minimal. N gear is generally used for short stops. Additionally, use N gear when towing the car. 4. D gear is the drive gear: When the gear lever is in D gear, the transmission gears automatically shift between the lowest and highest gears based on factors like speed and throttle opening, following preset shifting patterns. D gear can be used for driving in most situations.

[StMason]

Just put it in P gear when warming up the car. I do this every day when starting. P gear locks the transmission, so even if the handbrake fails, the car won't roll, which is especially safe. If you warm up the car in N gear, you have to keep your foot on the brake until it goes numb, and over time, the brake pads can easily overheat. I remember one winter when I was driving an old Camry, I warmed it up in N gear and didn't press the brake firmly enough—it almost rolled back and hit a wall, giving me a real scare. Nowadays, automatic transmission technology has improved, and putting it in P gear won't stop the transmission oil pump like in older cars, so there's no need to worry about lubrication issues. The key to warming up is watching the tachometer—once it stabilizes below 1000 RPM, you're good to go. Staying idle for too long can actually cause carbon buildup.

[LaylaLynn]

As an automotive enthusiast who has studied transmission structure manuals, the conclusion is that using P (Park) gear is superior. In P gear, the transmission output shaft is locked by a parking pawl, keeping the vehicle completely stationary. While N (Neutral) gear disengages the drivetrain, there's still a risk of rolling on flat ground, and brakes must be applied on slopes. I conducted an experiment: idling in N gear with brakes applied for five minutes caused brake disc temperatures to surge by 65°C, making the wheel hubs too hot to touch. However, it's important to firmly engage the parking brake after shifting to P gear to reduce strain on the transmission's parking mechanism. Some German vehicle manuals explicitly specify 'P gear idling' - for instance, my BMW 3 Series manual states this requirement in Article 147 on page 147.

[RhettDella]

A veteran mechanic with ten years of experience told me that if a car experiences jerky gear shifts after warming up in P gear, it's likely because the owner didn't wait for the RPM to drop before stepping hard on the accelerator. When the parking pawl in P gear engages the gear, and the transmission fluid hasn't warmed up, forcing a gear shift can cause a 'click' sound and damage the mechanism. The worst case I've seen was a Highlander owner who, after warming up in P gear, immediately shifted to D gear and accelerated hard, resulting in an 8,000-yuan repair bill for the transmission valve body. So the correct procedure is: shift to P gear → wait for RPM to stabilize → press the brake → wait two seconds → shift to D gear.

[LeDaniela]

From a physical principle perspective, the engine load is at its lowest when in Neutral (N) gear, theoretically making warm-up more efficient. However, the actual difference is negligible. I tested a 2.0T Passat: it took 3 minutes and 15 seconds for the coolant temperature to reach 60°C in N gear, while in Park (P) gear, it only took 8 seconds longer. What truly harms the car is turning on the heater immediately after starting in cold regions. Using N gear in this scenario can cause battery voltage fluctuations. I once tested this in Harbin at -20°C: with N gear and the heater on, the voltage dropped to 11V, triggering frantic warnings from the onboard computer. For northern car owners, it's advisable to warm up the car in P gear and turn off high-power electrical devices.

[LeIvan]

Veteran drivers know that in the carburetor era, it was necessary to warm up the car for ten minutes while stationary, but with modern fuel-injected vehicles, it's really unnecessary. I usually start driving slowly in D gear after 30 seconds of ignition, which is more efficient than idling in any gear. However, if stationary warm-up is unavoidable (such as in sub-zero temperatures), according to the SAE (Society of Automotive Engineers) technical report, it's recommended to engage P gear and activate the electronic parking brake. Test data shows that when warming up in N gear, the driveshaft still carries a residual torque of 0.5-1.2 N·m, which actually increases component wear. Last year, when I warmed up my Model 3 in N gear on snowy ground, the driveshaft noise was due to this very reason.