0w40 vs. 5w40 Motor Oil

If you value your car, then it is vital for you to identify the best oil for its engine. Engine is the most significant component in a car, as it facilitates locomotion of the entire car. It is an inherent responsibility for cars owners to determine and utilize the best oils for the engine. The best way for car owners to ensure proper care of car engine is through identifying and using the high quality oil that can be used in the engine (Rudnick, 2013). Oil is said to be the lifeblood for a car engine.

The basic functions of the oil include reducing friction, sealing, protecting moving parts, cleaning and cooling engine (Rudnick, 2013). Oil as a lubricant provides a fluid barrier between moving parts thus preventing wear and tear through friction.

Motor oil that can flow under prevailing weather conditions is written with the index “W” that signifies the behavior during winter. A lower index number for an oil illustrates the greater ability of oil to flow at lower temperatures, while as the temperatures increase, the oil becomes more viscous hence reducing its effectiveness in friction of moving parts. Lacking coating layer of oil to lubricate the moving parts of the engine can lead to overheating, grinding and engine breakdown.

0w40 vs 5w40 ambient temperature


The 0W40 Castrol’s oil is wholly synthetic and it is liquefied engineered to flow like 0 weight oil especially in regions that experience winter temperatures’, but to have viscosity of a 40 weight engine oil when high operating  temperatures’ has been attained. Therefore this ensure that the engine gets the required level of protection immediately after the engine has been ignited (Streather, 2016). 0 weight indicates that the oil flows like 0 weight in cold regions and further it can offer engine protection for 40 weight when the engine attains its full operating temperature.

The advanced synthetic properties provide proprietary anti-wear technology that is necessary for car engine. The exceptional performance of 0w40 offers the viscosity that needed to reserve the engine effective functioning, a property that conventional motor oils lacked. Even after reaching the maximum use, the oil provides excellent fuel performance hence enhancing economic benefits. Some of the exceptional quality of 0w40 is the ability keep engine running as new for a longer time, it improves engine lubrication and reduces chances of wear and tear of moving parts, additionally, it works effectively even at low temperature zones. The oil has been proven to facilitate the ability of engine to utilize low fuel a factor that shows the economical need to use it in your car (Streather, 2016). Further, 0w40 have the exceptional cleaning power of dirty engines and therefore it advances protection and prolongs the effective performance of engine.

0W40 retails at market price of about US $ 0.5 – 0.7 for every 550ml. Most manufacturers recommend 10,000km before replacement of the oil, thus making it economical to use this oil.


The 5w40 engine oil is fully synthetic and it is engineered to flow like 5 weight oil from a cold start in season temperatures and as a 40 weight when oil has attain its standard functioning temperatures.

The prefix number 5 implies that the oil has a viscosity of 5 in areas with temperatures of 0 degrees Celsius while at 100 degrees Celsius, the oil has a viscosity of 40. Therefore, 5W40 is suitable in high temperature zones like Africa (Rudnick, 2013), and most car manufactures claim that it is most suitable oil especially for new cars.

It helps protect engine from friction that causes wear and tear, additionally, it protects engine from deposit build-ups that in turn may destroy the engine after some time, hence proving the economic value of using this oil for your car (Rudnick, 2013). Replacing car engine may be an expensive affair, and therefore using an oil that protects your engine from wear as well as build-up of deposits will help prolong engine life and keep it effective for long.  

Further, the oil ensures efficient engine ignition and swift oil circulation in freezing environments, and gets the parts moving quickly (Streather, 2016). The suitability of using the oil in both cold and hot temperatures makes it efficient and economical for car owners who keep on changing locations, especially long distance travelers who move from one region to another.

The current retail prices for 5W40 is around US $ 0.5 – 0.8 for 550ml, which makes it more economical to use, as it has an operation period of about ten thousand kilometers before replacement.

Differences between 0W40 and 5W40

Regardless of fact that 0W40 and 5W40 performs similar duty, both engine oils are not equal in terms of properties and performance. Therefore, the oil has a viscosity of 5W-40, which implies that at cold environment, it flows like 5 Weight, while in high temperatures, the oil is formulated to flow like 40 weight (Rudnick, 2013). 5W40 is engineered to withstand great pressure and increased temperatures of contemporary gas and turbo[D1]  diesel motor engines.

Both oils have the similar viscosity especially when heated to standard engine operating temperatures’ and therefore this element does not set them apart. Additionally, both oils are engineered to conform to needs of both diesel and petrol engines that makes them share common property (Streather, 2016). When ignited at high temperatures, both 5W40 and 0W40 burns at normal viscosity of 40, which implies the existence of common viscosity at high temperatures.

Additionally, the retail prices of both types oil is almost similar as their prices range between US $ 0.4 – 0.8 respectively.

The major differences between 0W40 and 5W40 engine are depicted in the viscosities variances especially when compared in low temperatures’ environment. 0W40 circulates faster in a car engine particularly during cold weather. Areas that experience high cold winters may have 0w40 as the recommended engine oil for cars, as it is more effective in lubricating car engine in cold weather (Streather, 2016).

On the other hand, 5W40 oil is said to be effective in both cold and hot temperatures’ areas, as it as have 0 weight in cold winter and which may not be effective in hot environment since it becomes too thin in hot temperatures hence reducing efficiency and therefore may not be effective like 5W40  (Streather, 2016). Since 0W40 flows like 0 Weight in cold temperatures while 5W40 flows like 5Weight in cold temperatures, and therefore the viscosity properties especially in cold winter highlights the major differences between the two types of oils.


With the above information regarding the major differences between 0W40 and 5W40, it is easier for a car user to determine the best oil for their engines for more effective performance. As motor oil is the vital component of a car, it is necessary to have adequate information regarding various types of oils and their properties so as one can make an informed choice on the type of oil to use. Therefore, it can be recommended that for car owners living in cold areas to utilize 0W40, while those owner who live in high temperature zones should use 5W40 for their car engines.


Rudnick, L. R. (2013). Synthetics, Mineral Oils, and Bio-Based Lubricants: Chemistry and Technology, Second Edition. Boca Raton, FL: CRC Press.

Streather, A. (2016). Porsche 997 2004-2012: Porsche Excellence. Veloce Publishing.