Mazda Trucks 1987-1993 Repair Guide

Fuel and Engine Oil Recommendations



See Figures 1, 2 and 3

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Fig. Fig. 1: Lubricant specifications sticker located on the underside of the hood-MPV shown

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Fig. Fig. 2: Engine oil viscosity chart

The recommended oil viscosities for sustained temperatures ranging from below 0°F (-20°C) to above 32°F (0°C) are listed in this Section. They are broken down into multi-viscosity and single viscosities. Multi-viscosity oils are recommended because of their wider range of acceptable temperatures and driving conditions.

Mazda recommends that SAE 5W-30 viscosity engine oil should be used for all climate conditions, however, SAE 10W-30 is acceptable for vehicles operated in moderate to hot climates.

When adding oil to the crankcase or changing the oil or filter, it is important that oil of an equal quality to original equipment be used in your truck. The use of inferior oils may void the warranty, damage your engine, or both.

The SAE (Society of Automotive Engineers) grade number of oil indicates the viscosity of the oil (its ability to lubricate at a given temperature). The lower the SAE number, the lighter the oil; the lower the viscosity, the easier it is to crank the engine in cold weather but the less the oil will lubricate and protect the engine in high temperatures. This number is marked on every oil container.

Oil viscosities should be chosen from those oils recommended for the lowest anticipated temperatures during the oil change interval. Due to the need for an oil that embodies both good lubrication at high temperatures and easy cranking in cold weather, multigrade oils have been developed. Basically, a multigrade oil is thinner at low temperatures and thicker at high temperatures. For example, a 10W-40 oil (the W stands for winter) exhibits the characteristics of a 10 weight (SAE 10) oil when the truck is first started and the oil is cold. Its lighter weight allows it to travel to the lubricating surfaces quicker and offer less resistance to starter motor cranking than, say, a straight 30 weight (SAE 30) oil. But after the engine reaches operating temperature, the 10W-40 oil begins acting like straight 40 weight (SAE 40) oil, its heavier weight providing greater lubrication with less chance of foaming than a straight 30 weight oil.

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Fig. Fig. 3: Look for the API oil identification label when choosing your engine oil

The API (American Petroleum Institute) designations, also found on the oil container, indicates the classification of engine oil used under certain given operating conditions. Only oils designated for use Service SG heavy duty detergent should be used in your truck. Oils of the SG type perform may functions inside the engine besides their basic lubrication. Through a balanced system of metallic detergents and polymeric dispersants, the oil prevents high and low temperature deposits and also keeps sludge and dirt particles in suspension. Acids, particularly sulfuric acid, as well as other by-products of engine combustion are neutralized by the oil. If these acids are allowed to concentrate, they can cause corrosion and rapid wear of the internal engine parts.

Non-detergent motor oils or straight mineral oils should not be used in your Ford gasoline engine.

Synthetic Oil

There are many excellent synthetic and fuel-efficient oils currently available that can provide better gas mileage, longer service life, and in some cases better engine protection. These benefits do not come without a few hitches, however; the main one being the price of synthetic oils, which is three or four times the price per quart of conventional oil.

Synthetic oil is not for every truck and every type of driving, so you should consider your engine's condition and your type of driving. Also, check your truck's warranty conditions regarding the use of synthetic oils.

High mileage engines are the wrong candidates for synthetic oil. Older engines with wear have a problem with synthetics: they "use" (consume during operation) more oil as they age. Slippery synthetic oils get past these worn parts easily. If your engine is "using" conventional oil, it will use synthetics much faster. Also, if your truck is leaking oil past old seals you'll have a much greater leak problem with synthetics.


All of these vehicles must use lead-free gasoline. It is recommended that these vehicles avoid the use of premium grade gasoline. This is due to the engine control system being calibrated towards the use of regular grade gasoline. The use of premium grades may actually cause driveability problems. Also, Mazda advises against the use of gasoline with an octane rating lower than 87 which can cause persistant and heavy knocking, and may cause internal engine damage.


If you plan to drive your vehicle outside the United States or Canada, there is a possibility that fuels will be too low in anti-knock quality and could produce engine damage. It is wise to consult with local authorities upon arrival in a foreign country to determine the best fuels available.