Ford Explorer, Maintaince And Repair Manual

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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.
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.
CAUTION
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
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104 ENGINE OIL