There is absolutely no immediate danger for damage when a mineral oil is mixed with a synthetic oil, provided that the quality (classification according API, ACEA or OEM …) is the same. The reason for this is that the different components of these oils are compatible with each other.

Also, engine oils of different viscosities (like 10W30 and 10W40 or 15W40 and 20W50) can be mixed. In fact it happens frequently that different oils are mixed together. It can be unintentionally, without noticing, or simply when the filled-up oil is not available at the moment of topping-up and no other choice is left than to mix different oils.

It should however be kept in mind that mixing mineral and synthetic engine oils is not preferable. The same applies for mixing engine oils of different viscosities. These mixtures may on the longer term have a negative effect on the performance of the engine.

Best is to stick to the quality and viscosity of engine oil being filled-up already and that is meeting all the properties the vehicle manufacturer prescribes. In case topping up of the oil is necessary and the same oil is not available, best is to drain the used oil and fill up the engine with the other oil (and that is meeting OEM prescriptions).

Obviously, oil is slippery and as such reduces friction and prevents wear to occur by developing a lubricant film between the moving components. In case the film brakes down at some location inside the engine and two surfaces start rubbing against each other, likely the engine will not last long anymore.

It prevents the deposit of sludge on the surfaces of the engine by keeping these unwanted products well dispersed in the oil. Particularly soot dispersancy capacity of modern diesel engine oils is very important.

It cools off the moving components of the engine and removes the excess heat. The crankcase oil temperature rises and kept at an acceptable level by the airflow passing along the outside crankcase surfaces or either in an oil cooler installed in the oil circuit.

Furthermore engine oil, amongst a large number of functions can reduce fuel consumption, protect the engine against rust and corrosion, counteract the influence of the combustion acid formation, have detergent capacity and clean the engine inside, protect against ring sticking and formation of lacquer, help sealing engine parts and be compatible with joint materials that are being used.

The engine oil is essential for the proper functioning and acceptable life time of the engine. From a good quality oil the vehicle driver or owner can expect an optimum lubrication whatever the circumstances! A quality oil equals at least the requirements for modern gasoline and/or diesel engines.

Nowadays oil manufacturers or marketers of quality engine oils offer a most complete selection of engine oils, allowing the consumer to easily find the appropriate engine lubricant for the type of engine that is to be serviced.

After some time additives are less active or not so active anymore. Their efficiency in the base oil in which are mixed decreases below acceptable level.

The contamination of the oil starts to become too important so that the oil can't control it and no optimum lubrication takes place. Because of this contaminants, the oil not only becomes darker, but no optimum lubrication takes place anymore.

At a later time the dirty particles can't be kept in suspension any longer. They are deposited in the engine and possibly create as such a dangerous blocking situation.

Usually the viscosity increases during use, in cold as well as in operating temperature. This is due to the oxidation of the oil

Increased oil consumption may start to develop as well.

The risk for dangerous corrosion gets substantially higher.

The protection of the engine and the life span of it is affected in a negative way. Therefore after certain mileages the oil needs to be drained off and renewed. In case of vehicles performing only low annual mileages, oil drains are recommended on time basis rather than on ran distances or working hours.

In general prescribed drain intervals cannot be extended in a sufficiently safe manner without tight laboratory engine oil quality follow up.

First of all, obviously the Petronas oil products data and recommendations are easily accessible for technical support from the manufacturer Petronas Lubricants. Everybody can check easily the suitability of a particular Sunoco oil from the Website and the lubricant recommendations for lots of equipments.

Good and reliable advice is frequently given by the Sunoco specialized distributor or trader who on his turn is supported by the Petronas Lubricants technical department.

Furthermore autoparts shops, garages, retail oil businesses and do-it-yourself oil businesses can help as well by giving advices!

There is quite a difference, for sure !

Indeed, performance in diesel service is not needed for motorbike lubrication! As such, performance additive chemistry is different and balanced for gasoline performance!

Because of mechanical differences between cars and motorbikes (as is often the case with submerged clutches in motorbikes that do not exist in the car world), it is essential to use other oil formulations for your two wheeler than for your car engine. It has more particularly to do with the additives that control the slipping behaviour of the clutch on many motorbikes.

Car engine oils that contain even but a small amount of friction modifier agent won’t allow the clutch to operate properly in many cases, but will annoy the bike rider and on the long time cause wear and clutch problems .

So one can be convinced that there is really an essential difference between oil for a car and oil for a motorbike engine.

The SUNOCO logo was created at the end of the nineteenth century (1894) and has been the symbol for quality and reliability regarding lubricants ever since.

Throughout its history, there have been noticeable changes, but meanwhile the recognizability of the SUNOCO logo has been spread all over the world.

January 1st 2000 was the starting signal for a new and dynamic millennium. SUNOCO emphasized that dynamism through modernising its logo which is still actual.

The logo consists of a yellow checker which originally symbolised a diamond (because of the takeover of the Diamond Oil Company), perforated by a red arrow, which indicated, at that time, the direction of the service station where the SUNOCO products were available.

The brand-name SUNOCO, acronym of (former) SUN Oil COmpany, is placed centrally in the logo.

Petrol and diesel engines have different lubrication requirements.

During development, lubricants undergo a number of tests, some common to diesel and petrol engines and others specific to one or the other type, that categorize their performances. At the end of this process, they are awarded an API, ACEA or OEM compliance standard. These specifications characterize the acceptable functioning of the lubricant in each type of petrol or diesel engine. Lubricants for four-stroke engines usually comply with both petrol and diesel specifications. For example, an API SJ/CF lubricant meets petrol specification SJ and diesel specification CF. But this does not necessarily mean that it will perform in the same way in both petrol and diesel engines.

The engine oil level should be checked regularly to prevent incidents.

A small amount of the oil that circulates in the engine is always burnt (an engine in good condition consumes maximum between 0.2 and 0.5 liters of oil every 1,000 kilometers), but successive top-ups are no substitute for an oil change.

Accordingly, it is natural that an engine consumes a small amount of oil, which can be offset by top-ups between oil changes; however, excessive need for top-ups can be an indication of mechanical problems (leaks, etc).

Semi-synthetic and synthetic oils are made from non-conventional bases using sophisticated chemical processes which confer special properties to the finished product.

First, the high level of viscosity of the base oils used gives the finished lubricant remarkably stable viscosity whatever the temperature. This property is one of its major advantages over mineral oils, made from conventional bases which require a greater number of additives in order to improve viscosity.

The stability of lubrication in all temperatures guarantees optimum efficacy in the cold starting phase which is particularly demanding on the engine, as well as under conditions of extreme heat. Synthetic-based lubricants show greater resistance to oxidation, which gives them longer effective life thus guaranteeing longer engine life.

The use of non-conventional bases, finally, permits the elaboration of more fluid lubricants, without being more volatile; resulting in a reduction of oil consumption. Therefore, choosing a synthetic based oil is the technologically advance choice, for greater efficacy, longevity and controlled oil consumption.

A multigrade oil is one whose properties have been artificially modified to reduce changes in its viscosity with temperature changes.

A multigrade oil will be more fluid at low temperatures and thicker at high temperatures than a monograde oil. Concretely, that means that when the vehicle is not being used (for several hours), the engine oil sinks in the crankcase so that, on starting, it takes a certain amount of time (a few microseconds) to again reach all parts of the engine that need to be lubricated. Since a multigrade oil is more fluid at low temperatures, it reaches the various engine components more quickly than a monograde oil, thereby reducing wear on starting.

Multigrade oil allow "saving fuel" around 1.5% to 3% then monograde oil. Multigrade oils provide better engine protection at low and high temperatures than monograde oils, in that they maintain optimum viscosity over the engine operating temperature range.

The reply is clear and net: NO.

This challenge has been met by the CATALYTIC CONVERTER, whose role is to complete the combustion of the exhaust gas just before they escape into the atmosphere. In order to respect the environment oils must offer a high lubrication property, better detergent and dispersant properties as well as a low sulphur and phosphorous content. These properties are essential for oils that will be used in vehicles equipped with catalytic converters.

The use of a non adapted oil can damage the catalytic converter. Synthetic lubricants are highly recommended because of the intrinsic properties of their base.

There can be several reasons for that :

The relief valve setting may be too low : oil may flow from pump through the relief valve and back to the oil reservoir, this without reaching the point of use. To check the relief setting , block discharge line beyond relief valve and check the line pressure with pressure gage.

The relief valve is perhaps stuck open : this is likely due to dirt or sludge in the valve ! Disassemble and clean. This condition may indicate that the system contains deteriorated (dirty) oil. Then drain oil and fill up the system with new oil, resistant to deterioration.

Leak in the system : system should be checked for leaks. Install pressure gage in discharge line near pump and then block off circuit progressively . When gage pressure drops with gage installed at a given point, leak is between this point and check point just before it.

Broken, worn or stuck pump parts : look for mechanical trouble in pump. Replace worn or broken parts.

Incorrect control valve setting or oil “short-circuited” to reservoir : oil can return to reservoir without meeting any appreciable resistance and only very little pressure will be developed then. Correct valve setting or short-circuit.

Here also several reasons are possible :

The oil viscosity is too high : check oil recommendation. It may be worthwhile to drain the system and install oil of proper viscosity. Unusual temperature conditions may cause oil of proper viscosity for “working temperature” to thicken too much on way to the pump. In this case use of oil with higher viscosity index may cure the trouble.

Internal leakage is too high : check for wear and for loose packing spots . Oil viscosity may be too low. Check recommendations. Under unusual working conditions temperature may go high enough to reduce viscosity of recommended oil too much. Proceed with caution when trying a higher viscosity oil.

High discharge pressure : a too high setting of the relief valve could be the cause. If so reset.

Oil cooler clogged : on any machine equipped with an oil cooler, it is probable that high temperatures are expected. They will give even higher ones in case oil cooler passages are clogged. Try blowing out these passages with compressed air. If this doesn’t work, try solvents.

Poorly fitted pump parts : this may cause undue friction. Look for signs of excessive friction, make sure all parts are in alignment.

Following are possible causes :

Air leaking into system : oil reservoir is to be filled up to normal level and oil intake is below oil surface. Check pump packing, pipe and tubing connections and all other points where air might possibly leak into system. Pour oil over suspected places on the intake side . In case pump noise stops, you’ve found the leak.

Air bubbles in intake oil : if oil level is low or return line to reservoir is installed above oil level, air bubbles will be forming oil in reservoir.

Cavitation (=formation of vacuum in pump) : check for clogged or restricted intake line, plugged air vent in reservoir. Oil viscosity may be too high. Check recommendations !

Stuck pump vanes, valves, pistons : all these may cause (abnormal) noise and or higher noise level

Filter or strainer too dirty and/or filter too small : filters and strainers must be kept clean enough to permit adequate flow. Use hydraulic oil of high quality to prevent rapid sludge formation.

Pump running too fast : determine recommended speed. Check pulley and gear sizes. Do not use motor drive with other than recommended speed.

Pump out of line with driving motor : check alignment. Misalignment may be caused by temperature.