Engine oil is pressured in areas where ambient temperatures are constantly high, like in some areas of north-eastern Asia, the Middle East, Africa, and Latin America, then beyond normal operating temperatures. Although engine heat per se is maximum during combustion, the high baseline of the environment in which it operates causes the temperature of the sump to rise considerably, and regularly brings it nearer to its thermal maximumes even during moderate driving.
People believe that an increase in the quality of oil will resolve the problem of hot weather. Nevertheless, engine oils that have not been developed to operate at high temperatures may experience a rapid oxidation process and suffer the loss of viscosities in the hot weather countries. The secret is in the balancing of formulations: engine oil used by countries with hot climate cannot but be able to remain stable in its viscosity and in its resistance to oxidation in conditions of prolonged high temperatures.
This method will provide uniform film strength, less wear and increased service life. To get a variety of prospects to fulfill these need, explore our engine oil product category.
Why Hot Climate Countries Place Extra Stress on Engine Oil
Even initial requirements of engine lubricants are different in hot climate countries. The ambient temperatures are sometimes above 35-45oc for long periods and this gives a greater initial oil temperature before the engine is even started.
This high base causes a rise of sump temperatures by 10 to 25 o C over temperate regions, promoting thermal stress. Those engines in these regions are often left to work at long high-load conditions – consider heavy traffic or towing or even a fleet of commercial vehicles constantly in motion – aggravating the accumulation of heat. The cooling systems are more vigorous, but fewer and more severe thermal cycles are observed in oil.
The result? Rapid degradation in case the oil is not thermally resilient. Even higher quality oils, without high temperature very robust capabilities, are able to run thin or are deposited too early.
Viscosity Stability at High Temperatures
Protective film can be maintained at a constant level when exposed to heat conditions are likely to degrade lubrication. With increase in temperature, traditional oils become thinner, limit their capacity to separate moving components and prevent contact of metal to metal.
Stability Viscosity Viscosity stability is the tendency of the oil to resist this thinning. Synthetic or well-additized blends that are of high quality retain their thickness much longer at working temperatures (usually 100150 C within the engine). This maintains the strength of oil films on bearings, camshafts and cylinder walls despite the external heat that causes additional load.
A higher starting viscosity is not always good enough–viscosity stability is what is important than starting thickness as the unstable oils become useless very soon. To get a more detailed understanding of the effects of temperature, see our guide on heat and cold effects on engine oil viscosity.
Oxidation Resistance — A Critical Requirement in Hot Climates
One of the major degradation mechanisms in high temperature conditions is oxidation. The heat in the reaction of the molecules of oil and oxygen disaggregates the molecules of the base stocks and the additives.
This results in the production of acids, sludge and varnish, which cover internal surfaces, block the flow of oil and reduce the time taken to drain oil. In hot climate nations, where sump temperature remains high at a longer duration, the rate of oxidation is much higher- in some cases, a 100 C increase in degradation rate doubles the degradation rate.
Strong antioxidant packages and stable base stocks (such as synthetics) in oils prevent such breakdown in much longer times assuring acidity control and cleanliness. Exceptional resistance to oxidation is a direct extension of the oil life and prevention of failures related to the deposits. Find out more on oxidation stability on oxidation stability in engine oil.
Viscosity Index and Its Role in High-Temperature Performance
Stable behavior over temperature variations cannot be compromised by low viscosity index (VI). VI is a measure of how the viscosity of an oil varies with temperature its value being high results in a low temperature-viscosity curve.
Low VI oils in hot climates tend to thin out at high temperatures and this means that the oils do not protect effectively at the time that they are required most. In high-VI formulations (150 and above in good synthetic quality) sufficient thickness is maintained in areas where it matters most, which wear out less under sustained, heavy, heat loads.
It is obvious: unstable oils can fall to dangerous levels of their viscosity within a short time, whereas its stable analogs provide sufficient continuous strength of the film during the duty cycle. To get some real-life information, check our explanation of hot climate engine oil requirements.
Choosing the Right Viscosity Grade for Hot Climate Countries
The choice of SAE grade is a compromise of both cold-flow requirements (even that of the tropics at lows of 2035C) and hot-work protection. Recommendations of manufacturers can be taken as the basis, although regional trends are inclined towards multi-grades that do not thin too much.
Usual options are 10W-40 or 15W-40 in mixed fleet, which offers acceptable high temperature film without compromise in pumpability. The light grades such as 5W-30 are used in modern passenger cars that have strict tolerances, but with superior stability additives.
The expectation: hot viscosity necessary to protect but not too much that will slow down and reduce the performance. Never hesitate to reference OEM specs. See similar instructions on using engine oil for hot climate countries.
Engine Type Differences in Hot Climate Operation
The thermal characteristics of diesel and gasoline engines differ under hot conditions. Trucks and other machinery that use heavy-duty diesels, which dominate the emerging markets, produce higher combustion pressures and exhaust temperatures, stricter loads on oil.
This contributes to a higher soot loading and thermal stress which requires vast detergency and oxidation resistance. assenger cars with gasoline engines experience more city heat cycles involving stop-starts, however, with lower peak loads, nevertheless, with requirements of stable viscosity to prevent shearing when operated over extended periods.
Efficiency may also vary in cooling systems; the older system or one that is heavily loaded may overrun and increase oil requirements. These nuances can be understood in order to match formulations. See more on the topic of differences in our article about diesel vs gasoline engine oils understating the differences.
Comparing Common Oil Grades Used in Hot Climate Markets
Selection of grades is usually application and fleet-driven. A comparison of the popular choices in hot areas would be as follows:
| Oil Grade | Typical Application | High-Temperature Stability |
| 5W-30 | Modern passenger cars | Moderate |
| 10W-40 | Mixed-use vehicles, light commercial | Good |
| 15W-40 | Heavy-duty / fleets, trucks | Very good |
These grades give increasingly high levels of film strength at high temperatures, 15W-40 being able to operate in more rigorous circumstances because of increased hot viscosity. On comparisons further, read our analysis of high-temperature stability.
Regional Market Considerations Beyond Temperature
The central performance in countries with a hot climate is affected by other factors, with temperature being the main one. Equivalent additives are used to facilitate the wear and tear of poor fuel brands: The sulfur legal, or impurities are more active.
Bad driving behaviors such as waiting in traffic jams or overloading enhance heat cycles. Long service periods, which are typical of price sensitive markets require oils that have outstanding performance.
These need to be tackled in a holistic manner to guarantee improved real-life outcomes. To get advice that is specific to markets, best engine oil for high-temperature climates.
Common Misunderstandings About Engine Oil in Hot Climates
There are a number of myths that remain with the users and even certain distributors.
- Also, thicker oil is preferred: With an initially overly thick grade, the oil cannot flow at the start-up (were it hot outside as well) and the pumping costs more to operate and therefore the operating temperature rises, which is not protection, it is heating.
- Having cold-start properties is not important in hot countries: Even night or early morning low temperatures need good pumpability; bad coldness results in early wear.
- Any SAE grade oil will do, however: The additive package, base-stock quality and VI can differ across the board again- achieving the grade does not necessarily guarantee high-temperature retail.
Such premises frequently result in untimely failures when the actual requirements surpass bare minimum requirements.
Conclusion — Heat Resistance Is a System, Not a Single Property
The property that contributes to effective engine oil performance in hot climate countries has emerged as integrated, including constant viscosity over heat ranges, strong oxidation strength, high VI to provide curve flatness, and customized additive systems.
Neither can be considered as a single factor; formulation balance provides reliability in demanding environments that fleets of drivers and drivers of the fleet require. With these features as priorities, operators reduce wear, increase drain frequencies, and keep the engines healthy throughout the service.