What is the normal idling RPM when warming up a car?
2 Answers
Warm-up RPM should not exceed 3000 to 3500 RPM, and maintaining around 2000 RPM is generally normal. Both summer and winter require warming up the car, with winter requiring a longer warm-up period than summer. After sitting overnight, the lubricating oil on the engine's friction surfaces has mostly dissipated, leaving them without oil film protection. Low temperatures increase the viscosity of the lubricating oil, reducing its adhesion and flowability, which increases resistance when starting the engine. Proper idling warm-up can reduce this wear, thereby extending the engine's lifespan. At low temperatures, metals exhibit reduced elasticity and wear resistance. Only at normal operating temperatures can the engine achieve proper clearance and maintain optimal working conditions.
When it comes to warm-up engine speed, I think most cars idle steadily between 700 and 900 RPM, but it really depends on the vehicle itself. Take my regular gasoline car for example—once the engine warms up after starting, the RPM drops and usually hovers around 750. Temperature has a big impact on it: it might be slightly lower in summer and higher in winter. But don’t underestimate this—if the RPM is unstable, fluctuating up and down, it’s likely an engine issue, like carbon buildup on the spark plugs or a clogged air filter, which needs immediate cleaning. If the warm-up RPM is too high, exceeding 1,000 RPM, it could be related to a faulty idle control system; if it’s too low, below 600 RPM, the car will shake noticeably, indicating potential fuel system or ignition problems. When driving, I usually glance at the dashboard once the engine warms up—stable RPM directly affects fuel consumption and noise levels, so safe driving shouldn’t be taken lightly. If you notice any issues, I recommend getting it checked at a professional shop to prevent bigger problems down the road.
