Is it harm to race the cool engine ?
 

My car was left in the car park for a few days. This morning, I started the engine with the automatic transmission selector lever in the 'Neutral' position, the accelerating pedal was accidentally pressed all the way down for few seconds. What is the bad effect on the engine and other parts of the car?

Chow

Thanks in advance.

It really depends on the car. If your car is newer and has a rev limiter in place, then the damage is probably minimal if at all. If it is an older car and doesn't have one, you would already know because your car probably wouldn't be running right now.

Personally, I wouldn't have thought twice about it if I accidentally pressed the gas pedal down for a few seconds while in neutral (maybe now I would because of wasted gas, but that's all). However, I'm not a car expert so there may be something, like valve damage or something, but I can't speak for that.

The thing to worry about with revving an engine immediately after start up is engine wear due to lack of oil. During the time between cranking and oil getting to all the engine parts a lot of wear can happen. As soon as the oil is circulating through it you are okay. However, doing this once is not going to kill the engine. Just don't make a habbit of it.


BTW, welcome to the site.

Agreed -- not a big deal unless you do it all the time.

The hardest I've been on an engine was running for volunteer EMS/Fire ( with a new '97 Civic DX Coupe, 5-speed). Cold soak, start, high electrical loads (lights/siren), at least 2 redline runups and high RPMs for engine braking, 2.5 minutes to the station, and shut down for at least 2 hours on the average before returning home. Seconds counted, so the vehicle was put through the paces to accomplish the task.

I was warned that it could prematurely blow the head gasket with the wide swings in temps. All that happened was warped rotors with the hard stops. The vehicle was nearly totaled with a rear-end collision while stopped, just driving home. It was just over a year old. Never the same again, for sure.

Welcome, by the way!

RH77

And welcome from Hong Kong!

Never rev a cold engine! Let it warm up for several minutes so that everything warms slowly. The engine might not be properly lubricated if you race the engine off the bat.