At what temperature of the oil you can start the movement: a complete analysis

The question of what temperature of oil to start driving has been one of the hottest debates among motorists for several decades. Some drivers are convinced that it is necessary to warm up the engine to a working temperature of 90 degrees, standing still, while others insist on the immediate start of movement immediately after start-up. The truth, as is often the case in technical matters, lies in the middle and depends on a variety of factors, including the viscosity of the lubricant, engine design and weather conditions.

Modern engines are significantly different from the units of the Soviet era or early foreign cars of the 90s. Engineers changed tolerances between rubbing vapors, introduced new lubrication systems and changed the requirements for the oils themselves. Cold launch. It is the most stressful moment for the engine, and it is the right actions of the driver in the first minutes that determine how long your car will last. Understanding the physical properties of motor oil at different temperatures will help avoid costly repairs.

In this article, we will analyze in detail the physicochemical processes occurring in the engine at low temperatures, determine the optimal parameters of the thermometer for starting the movement and find out why long warming up on idles can be even more harmful than careful driving. We will consider the effect of viscosity, types of oil filters and features of the work. hydrocompensator in the winter.

Physics of the process: how does oil behave in the cold

To understand when to move, you need to understand the behavior of the fluid inside the engine. Motor oil is not just a lubricant, it is a complex mixture of base oils and a packet of additives. When the temperature decreases, its viscosity increases sharply. If in summer the oil resembles water or liquid honey, then in severe frost it turns into a thick jelly or even into a solid mass. Pumpability In this state, it is critically reduced.

In the first seconds after the starter start, the oil pump should capture a thick liquid from the crankcase and apply it under pressure to the most remote points: camshafts, turbines, phase rotators. Until that happens, the engine is running in mode. oil-starve. The main load falls on the crankshaft liners, which, however, have some oil reserve after the previous trip. However, the HRM chain drives and the upper part of the cylinder head are affected first.

⚠️ Attention: It is critical to understand that the temperature sensor on the dashboard shows the temperature of antifreeze, not oil. The liquid in the cooling system warms up faster than the volume of oil in the crankcase, so you can not focus on the arrow of the cooling liquid when deciding to start moving.

There is a concept of “colding temperature”, but it does not mean that the oil has turned into ice. This is the temperature at which the oil loses its mobility. However, even long before the point of solidification, it ceases to effectively lubricate. hydrodynamic wedge - the thinnest film between rubbing parts - at low temperature, either does not form or works inefficiently, which leads to dry friction and mycosadir.

Interestingly, modern synthetic oils behave differently than the mineral counterparts of the past. Due to their molecular structure, they retain fluidity at lower temperatures. However, physics is physics: thick oil requires more effort to pump, creating high pressure in the mainline to the filter bypass valve.

Critical indicators: when the pressure is normal

The main parameter that determines the readiness of the engine to load is not so much temperature as pressure. Once you have turned the ignition key or pressed the Start button, the emergency pressure lamp goes off on the dashboard. This means that the minimum pressure in the system is already there, and the oil pump was able to "push" the system. However, this is only a signal that the engine can be operated in a gentle mode, but not that it is ready for full load.

The time it takes to establish normal pressure depends on the viscosity of the oil and the ambient temperature. In winter, at -20°C, thick oil can circulate through the system for seconds or even tens of seconds after starting. At this point, the main wear of the engine, which is up to 70% of the total mileage life, occurs. That is why it is important to give the pump a few moments to fill the highways.

Consider the dependence of the warming time to the safe start temperature of movement on the type of oil and air temperature:

Type of oil	Air temperature	Time before the start of the movement	Mode first 5 km
Synthetics 0W-30 / 0W-40	-5°C to -15°C	30-60 seconds.	Splendid, up to 2,500 rpm
Synthetics 5W-30 / 5W-40	-15°C to -25°C	1-2 minutes	Very gentle, without any sharp acceleration
Semi-integrity 10W-40	0°C to -10°C	2-3 minutes	Medium, avoid high turnovers
Mineral oil	Below -5°C	Not recommended	Long warming up is required (10+ min)

As can be seen from the table, for modern synthetic oils with an index 0W or 5W Waiting time is minimal. The main task at this point is to let the oil spread through all channels. If you start moving immediately without letting the pump create a stable flow, you risk turning the liners or stretching the GRM chain due to the work of the tensioner without lubrication.

It is worth noting that some modern cars with turbocharged engines have electric oil heaters or additional pumps that are activated at start-up. They help to deliver the lubricant to the turbocharger faster, which somewhat mitigates the requirements for warm-up time on site.

Effect of viscosity on engine heating time

Viscosity is a key parameter that determines how quickly the oil will achieve performance. In the labeling of oils, for example, 5W-30, first digit with a letter W (Winter) indicates low-temperature viscosity. The number 5 indicates that the oil is tested for pumpability at -30°C and 0 at -35°C. The second digit (30, 40) characterizes the viscosity at the operating temperature of the engine (100 ° C).

Using oil with an inappropriate viscosity class in winter can lead to catastrophic consequences. If you pour the oil 10W-40 In the cold, it simply cannot pass through the filter element. The bypass valve will work, and unfiltered oil with metal shavings and combustion products will go to the engine. It's a straight path to bullies.

• 🧊 Class oils 0W remain fluid to extremely low temperatures, providing a quick start and minimal warming up time.
• 🛢️ Class oils 5W They are universal for most regions, but at temperatures below -25 ° C their pumpability drops sharply.
• ⚙️ Oils with high temperature viscosity (e.g., 40 or 50) thicker when heated but colder than class 30 It is not so noticeable if the base oil is of good quality.

It is important to understand that the “working temperature” of the oil is not 40°C or 60°C, but the range from 80°C to 100°C (and higher for sports motors). Only at these values, the oil has passport viscosity and protects the engine as much as possible. Before reaching this threshold, the loads should be minimal.

There is a myth that more liquid oil (for example, 0W-20) protects the engine less. In fact, modern engines are designed with minimal gaps for this viscosity. The use of thicker oil “just in case” leads to the fact that it does not have time to penetrate into narrow gaps, causing oil starvation in critical nodes.

Warming up in place or movement: what engineers say

The debate about the method of warming up is not subdued. Supporters of warm-up on the spot argue that the engine should warm up evenly, and only then you can drive. Engineers and oil manufacturers often write in manuals: “No warming is required, start driving right away.” Where's the truth? The truth, as usual, depends on the context.

Prolonged warming up at idle speeds (5-10 minutes or more) is harmful for several reasons. First, at idling, the engine runs on an enriched mixture, which leads to the washing of oil from the walls of the cylinders with gasoline. Secondly, the engine warms up unevenly: the head of the unit is already hot, and the pistons and cylinders are still cold, which creates thermal stresses. Third, it is simply fuel consumption and environmental pollution.

However, “moving at once” also needs clarification. This means the start of movement 30-60 seconds after start-up, when the pressure in the system fell and the idling speeds stabilized. But you need to move in a gentle mode: without sharp accelerations, at low speeds (up to 2000-2500 rpm), until the engine reaches the operating temperature.

⚠️ Note: You can not give full load on the cold engine, even if you stood for 15 minutes on idle. The oil in the crankcase could warm up, but in the channels of the block head and in the hydrocompensators it is still cold and thick. A sharp opening of the throttle at this point will cause a pressure jump and possible extrusion of the osteoils.

Modern engine control systems specifically keep increased speeds (1000-1200 rpm) in the first minutes after launch. This is not done for rapid warming up, but for rapid warming up of the catalytic converter. Trying to drive straight away can knock down ECU algorithms, although modern systems are adaptive and quickly rebuilt.

The best strategy is a combined approach: short-term warming up in place before a drop in turnover, followed by careful movement. This allows you to warm up the engine under load, but without extreme modes, and faster heat the transmission and hub bearings, which do not warm at all in place.

Features of heating diesel and turbocharged engines

Diesel engines require a more careful attitude to oil temperature than gasoline counterparts. Due to the high degree of compression and high thermal loads, the gaps in the diesel are often smaller, and the lubrication requirements are higher. In addition, diesel engines are longer at operating temperature, especially taking into account modern environmental standards and the presence of particulate filters. DPF.

Turbocharged engines, whether gasoline or diesel, have another vulnerable point: the turbocharger. The turbine shaft rotates at speeds up to 200,000 rpm or more. It is lubricated with the same oil as the engine. In cold start, while the oil is thick, the bearings of the turbine (often slipping, less often rolling) experience tremendous loads. Insufficient lubrication leads to rapid wear of the bushings and bullying of the shaft.

• 🌡️ The turbine heats up very quickly, but the oil in it can coke at a sharp stop of the hot engine, so after the trip you need a cooldown, and before the trip - a careful start.
• ⏱️ The heating time of the diesel engine on site should be slightly longer than that of the gasoline atmospheric, especially in winter, to warm up not only the lubricant, but also the elements of the Common Rail system.
• 🚗 For turbo engines, it is critically important to move the first kilometers of the way without sharp increases in boost pressure, so as not to create peak loads on cold nodes.

Owners of cars with turbines should pay attention to the presence of a preheater. Electric or liquid heaters greatly facilitate cold start, reducing the viscosity of the oil even before the starter is turned on. This extends the life of the turbocharger at times.

It is also worth mentioning the system of changing the phases of gas distribution (VVT-i, VTEC, VANOS). These systems work from the pressure of the oil. If the oil is cold and thick, the system may not work correctly or turn on at all, which will lead to unstable engine operation in the first minutes. Give the system a few seconds to adapt after launch.

Is it harmful to long warming up on idle?

Many old-school drivers are convinced that “7 minutes on singles and the engine will say thank you.” However, current research and practice show the opposite. Long-term idling at low temperatures leads to the fact that the engine operates on an enriched mixture. The fuel does not burn completely and flows down the walls of the cylinders into the crankcase, mixing with oil.

This phenomenon is called “oil liquefaction”. As a result, the oil loses its lubricating properties, and its volume in the crankcase may even increase. In addition, unburned fuel washes the oil film from the piston rings, which leads to increased wear of the cylinders at the moment when you seem to “keep” the engine. Nagaration on candles, valves and pistons with prolonged idling occurs more intensively than during movement.

Another negative factor is condensation. When working cold engine in the exhaust system and in the engine itself is formed a lot of water vapor. With short trips with preliminary long warming, the water does not have time to evaporate and remains in the oil, forming an emulsion. This leads to corrosion of parts and loss of additive properties.

The environmental aspect cannot be ignored either. At idling, the catalytic converter does not enter an effective mode of operation, and the maximum amount of harmful substances is emitted into the atmosphere. In many countries of Europe and the United States, long-term operation of the engine on site is even prohibited by law and is fined.

Thus, the “golden mean” is the time it takes for the oil to disperse through the system and drop the idling turns. It's usually 30-90 seconds. Further warming is more effective to produce in motion, gently working with the gas pedal.

What happens if you ignore the warm-up in a cold?

If you start the engine at -30°C on 5W-40 oil and immediately give the gas, you can get bullies in the cylinders due to the lack of oil film. In the worst case, a break in the HRM chain or a break in the tensioner is possible, since cold oil will not have time to create the necessary pressure in the hydraulic tension system. Repair of the engine after such a start-up can cost tens of thousands of rubles.

Practical recommendations for winter operation

Based on the above, it is possible to formulate a clear algorithm for the driver in the winter. The main rule: do not go to extremes. You do not need to wait until the temperature arrow rises from zero, but you can not tear from place on a cold engine.

Here is a general guide for most modern cars:

1. Start the engine. Let it work at idle speeds from 30 seconds to 2 minutes (depending on the temperature overboard and the viscosity of the oil).
2. Watch your turn. Once they have fallen from elevated (1200-1500) to normal unmarried (700-900), you can start moving.
3. The first 5-10 kilometers move in a gentle mode. Avoid sharp accelerations and engine braking. Do not raise the speed above 2500-3000 rpm.
4. Use heated seats and steering wheels instead of immediately turning the stove on at full power - this will help the engine warm up faster.

Pay special attention to the transmission. If you machine or variatorThey also require warm-up. The cold oil in the automatic transmission is thick, and sharp touching can damage the frictions. After starting the engine, press the automatic transmission selector in all modes with a delay in each position for a couple of seconds so that the oil disperses through the channels of the hydroblock.

⚠️ Note: If you only use your car for short trips (less than 5 km) in winter, the engine may not have time to warm up to operating temperature at all. In this case, it is recommended to make a long trip on the highway once a week to evaporate condensate from the oil and fuel system.

Do not forget about the quality of fuel and technical fluids. In winter, it is better to use fuel with a higher octane number and oils with a lower low-temperature viscosity index. This will ensure a confident start and quick lubrication of all nodes.

Frequently Asked Questions (FAQ)

Do I have to wait until the temperature arrow moves from zero before starting to move?

No, waiting for the rise of the arrow temperature antifreeze is not necessary and even harmful. The engine warms up in place for too long, and the arrow will move only after 5-10 minutes. It is enough to wait 1-2 minutes to stabilize the speed and spread the oil, after which you can start a careful movement.

Can I start moving immediately after the oil pressure lamp is extinguished?

Technically, yes, the lamp goes out when the pressure has reached a minimum threshold. However, in the first seconds, the oil is still very thick and has not filled all the nooks of the lubrication system, especially hydrocompensators and phase rotators. It is better to give the motor 30-60 seconds to work in calm mode.

Is it bad for the turbine if I drive right after launch?

Yeah, it's bad. The turbine rotates at a tremendous speed, and the presence of an oil film is critical for it. In cold start, the oil is thick and slowly flows to the bearings of the turbine. It is necessary to give the pump at least a minute to create a stable pressure before starting the movement.

Which oil is better for winter: 0W-30 or 5W-40?

For winter and cold start-ups is better suited 0W-30. It has better fluidity at low temperatures, which provides faster engine lubrication in the first seconds of operation. However, always follow the recommendations of your car manufacturer as indicated in the service book.

Is it true that the modern engine does not need to be warmed at all?

The phrase “do not need to warm” in the instructions means that long warming up in place to operating temperature is not required. But 30-60 seconds on idle oil circulation is necessary even the most modern engines. Instant start-up under load after launch is still harmful.