4

I bought a Honda Accord LX 2010 model, and I live in Detroit where -10C temperature is an everyday thing. I was advised by my friend to start the engine and let the rpm drop down a bit after which I can start driving the car. So immediately after starting the car it is always in 1500 rpm range. After waiting for a minute or so it drops down to 1200 rpm, after which I start driving it. I just wanted to know: 1. Is it necessary to wait like this for the rpm to drop or am I wasting gas unnecessarily? 2. If it is necessary then how do I know when it is good to start driving the car?

Please note that upon starting the engine, the car is running the front and rear defroster in almost full power, along with the radio.

4

The only requirement for the engine after start before power is applied is that enough oil is flowing to the camshaft, bearings and cylinder walls and piston rings. The cam and bearings are fairly easy to get oil to quickly, depending on oil viscosity this usually happens in less than 20 seconds. The cylinder walls and piston rings are the last to get oil because they are lubricated by splash and spray from the crankshaft. The oil splash works better at higher rpm and lower oil viscosity.

Best practice for the least engine wear in a very cold engine.

  • Use the lowest viscosity oil allowed by the manufacturer.
  • Run the engine without load for 30 seconds before driving.
  • Drive slowly with light loads for the first couple of minutes.

This gives the highest probability of adequate cylinder wall lubrication to reduce wear.

A higher idle rpm is needed when the engine is cold because poor fuel evaporation causes poor running and misfire at low rpm. This has little affect on engine but if anything would tend to improve life due to better piston ring lubrication. The usual design of the control software has the cold high rpm set in proportion with engine temperature at start.

| improve this answer | |
  • Your answer is perfect from the engine perspective, but can you elaborate from the perspective of the battery? Isn't battery wear/damage also a concern due to the weather? – Cool_Coder Feb 12 '17 at 1:11
  • Can you also tell me the reason why the rpm comes down automatically after a minute of idle running the engine? What is the significance of this pertaining the engine quality/life? – Cool_Coder Feb 12 '17 at 1:12
  • Battery: the cold temps do not in and of itself hurt a battery but if the engine has to be cranked longer this lowers state of charge which can have a small effect on battery life. Cold idle speed: see answer amendment. – Fred Wilson Feb 12 '17 at 3:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.