See Figures 1 and 2OIL
Chrysler Corporation recommends the use of a high quality, heavy duty detergent oil with the proper viscosity for prevailing conditions. Oils labeled SG/CC are satisfactory for use in all engines; however, a higher quality oil, labeled SG/CD is preferred.
Oil must also meet viscosity standards. Follow the chart below precisely. Make sure the oil you buy is clearly labeled so as to confirm to both these basic standards.
Use only quality oils. Never use straight mineral or non-detergent oils, that is, oils not equipped with special cleaning agents. You must not only choose the grade of oil, but the viscosity number. Viscosity refers to the thickness of the oil. It's actually measured by how rapidly it flows though a hole of calibrated size. Thicker oil flows more slowly and has higher viscosity numbers-SAE 40 or 50. Thinner oil flows more easily and has lower numbers-SAE 10 or 20.
Chrysler recommends the use of what are called "multigrade'' oils. These are specially formulated to change their viscosity with a change in temperature, unlike straight grade oils. The oils are designated by the use of two numbers, the first referring to the thickness of the oil, relative to straight mineral oils, at a low temperature such as 0°F (-18°C). The second number refers to the thickness, also relative to straight mineral oils, at high temperatures typical of highway driving (200°F (93°C)). These numbers are preceded by the designation "SAE,'' representing the Society of Automotive Engineers which sets the viscosity standards. For example, use of an SAE 10W-40 oil would give nearly ideal engine operation under almost all operating conditions. The oil would be as thin as a straight 10 weight oil at cold cranking temperatures, and as thick as a straight 40 weight oil at hot running conditions.
There are excellent synthetic and fuel-efficient oils available that, under the right circumstances, can help provide better fuel mileage and better engine protection. However, these advantages come at a price, which can be more than the cost per quart of conventional motor oils.
Before pouring any synthetic oils into your vehicle's engine, you should consider the condition of the engine and the type of driving you do. Also, check the manufacturer's warranty conditions regarding the use of synthetics.
Generally, it is best to avoid the use of synthetic oil in both brand new and older, high mileage engines. New engines require a proper break-in, and the synthetics are so slippery that they can hinder this. Most manufacturers recommend that you wait at least 5,000 miles (8000 km) before switching to a synthetic oil. Conversely, older engines are looser and tend to use more oil. Synthetics will slip past worn parts more readily than regular oil. If your truck already leaks oil (due to worn parts and bad seals or gaskets), it will leak more with a slippery synthetic inside.
Consider your type of driving. If most of your accumulated mileage is on the highway at higher, steadier speeds, a synthetic oil will reduce friction and probably help deliver fuel mileage. Under such ideal highway conditions, the oil change interval can be extended, as long as the oil filter will operate effectively for the extended life of the oil. If the filter can't do its job for this extended period, dirt and sludge will build up in your engine's crankcase, sump, oil pump and lines, no matter what type of oil is used. If using synthetic oil in this manner, you should continue to change the oil filter at the recommended intervals.
Cars used under harder, stop-and-go, short hop circumstances should always be serviced more frequently, and for these vehicles, synthetic oil may not be a wise investment. Because of the necessary shorter change interval needed for this type of driving, you cannot take advantage of the long recommended change interval of most synthetic oils.
A prime requirement for gasoline is the use of unleaded fuel only. All the vehicles covered in this repair guide require the use of unleaded fuel exclusively, to protect the catalytic converter. Failure to follow this recommendation will result in failure of the catalyst and consequent failure to pass the emission test many states now require. The use of unleaded fuel also prolongs the life of spark plugs, the engine as a whole, and the exhaust system.
Fuels of the same octane rating have varying anti-knock qualities. Thus, if your engine knocks or pings, try switching brands of gasoline before trying a more expensive higher octane fuel. Fuel should be selected for the brand and octane which performs without pinging.
Your engine's fuel requirements can change with time, due to carbon buildup which changes the compression ratio. If switching brands or grades of gas doesn't work, check the ignition timing. If it is necessary to retard timing from specifications, don't change it more than about 4°. Retarded timing will reduce power output and fuel mileage and increase engine temperature.
Basic engine octane requirements, to be used in your initial choice of fuel, are 87 octane, unleaded. This rating is an average of Research and Motor methods of determination: (R+M)/2. For increased vehicle performance and gas mileage use a premium unleaded fuel, that is, one with a rating of 91 octane. More octane results in better performance and economy in these engines because the ignition system will compensate for their characteristics by advancing the timing.
Gasohol consisting of 10% ethanol and gasoline may be used in your car, but gasolines containing methanol (wood alcohol) are not approved. They can damage fuel system parts and cause operating problems.