Chevrolet Blazer/Jimmy 1969-1982 Repair Guide

Fuel and Engine Oil Recommendations




All engines through 1971 are designed to use fuel of 91 research octane or higher. All 1972 and later engines, except those with a catalytic converter, use unleaded or low-lead fuel. All engines with a catalytic converter must use unleaded fuel.

Your engine's fuel requirement can change with time, mainly due to carbon buildup changing the compression ratio. If your engine pings, knocks, or runs on, switch to a higher grade of fuel and check the ignition timing as soon as possible. If it is necessary to retard timing from specifications, don't change it more than about four degrees. Retarded timing will reduce power output and fuel mileage and increase engine temperature.

Should you plan to operate your Blazer or Jimmy in a foreign country, you can contact the Chevrolet or GMC Owner Relations Department to obtain information on required engine modifications or adjustments and the quality of the fuels available there. Be sure to supply your vehicle's Vehicle Identification Number (VIN) and the engine's compression ratio if available.


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Fig. Fig. 1 Gasoline engine oil viscosity chart

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Fig. Fig. 2 Look for the API oil identification label when choosing your engine oil

Only oils labeled SE/SF are approved under warranty for use in 1972 and later models. Oils labeled SD were approved for 1971 and earlier models, since the higher quality SE rated oils were not generally available at that time. SE/SF oils should now be used in all models. Non-detergent oils are specifically not recommended. You can find the SE/SF marking either on the top or on the side of the oil container; the