GM Cutlass RWD 1970-1987 Repair Guide




The Society of Automotive Engineers (SAE) grade number indicates the viscosity of the engine oil and thus its ability to lubricate at a given temperature. The lower the SAE grade number, the lighter the oil; the lower the viscosity, the easier it is to crank the engine in cold weather.

Oil viscosities should be chosen from those oils recommended for the lowest anticipated temperatures during the oil change in interval.

Multi-viscosity oils (10W-30, 20W-50 etc.) offer the important advantage of being adaptable to temperature extremes. They allow easy starting at low temperatures, yet they give good protection at high speeds and engine temperatures. This is a decided advantage in changeable climates or in long distance touring.

The American Petroleum Institute (API) designation indicates the classification of engine oil used under certain given operating conditions.

Use only oils with the API service designation SF, SF/CC or SF/CD or better for gasoline engines and for diesel engines use only SF/CC and SF/CD or better. Oils of this type perform a variety of functions inside the engine in addition to their basic function as a lubricant. Through a balanced system of metallic detergents and polymeric dispersants, the oil prevents the formation of high and low temperature deposits and also keeps sludge and particles of dirt in suspension. Acids, particularly sulfuric acid, as well as other by-products of combustion, are neutralized. Both the SAE grade number and the API designation can be found on top of the oil can.


See Figures 1 and 2

Every time you stop for fuel, check the engine oil as follows:

  1. Make sure the car is parked on level ground.
  3. When checking the oil level it is best for the engine to be at normal operating temperature, although checking the oil immediately after stopping will lead to a false reading. Wait a few minutes after turning OFF the engine to allow the oil to drain back into the crankcase.
  5. Open the hood and locate the dipstick which will be on either the right or left side depending upon your particular engine. Pull the dipstick from its tube, wipe it clean and then reinsert it.

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Fig. Fig. 1: Pull the dipstick from its tube, wipe it clean and then reinsert it

  1. Pull the dipstick out again and, holding it horizontally, read the oil level. The oil should be between the FULL and ADD marks on the dipstick. If the oil is below the ADD mark, add oil of the proper viscosity through the capped opening in the top of the cylinder head cover.

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Fig. Fig. 2: Pull the dipstick out again and, holding it horizontally, read the oil level.

  1. Replace the dipstick and check the oil level again after adding any oil. Be careful not to overfill the crankcase. Approximately one quart of oil will raise the level from the ADD mark to the FULL mark. Excess oil will generally be consumed at an accelerated rate.


See Figures 3, 4, 5, 6, 7, 8, 9 and 10

Change your oil according to the Maintenance Interval Charts shown in this section.

Oldsmobile recommends that the filter be changed every other oil change, unless the vehicle is driven under those conditions requiring more frequent changes or those in which the time limit expires before the mileage limit. Our recommendation is that, regardless of the interval, the filter should be changed at every oil change. This offers excellent protection against a situation in which the filter becomes clogged, bypassing dirty oil directly to the engine's wearing parts. It also permits a more complete removal of dirty oil from the engine's filter and oil galleries, which hold a quart or more of contaminated fluid. Change the oil in diesel vehicles every 5000 miles (8000 km) On diesels, if you are towing a trailer, if it is dusty, or you are driving trips of four miles or less in below freezing temperatures, change the oil every 2500 miles (4000 km) or three months, whichever comes first.

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Fig. Fig. 3: By keeping inward pressure on the plug as you unscrew it, oil won't escape past the threads

The oil should always be changed while hot, so the dirt and particles will still be suspended in the oil when it drains out of the engine. Hot oil also flows better providing for a more complete removal of old oil. To change the oil and filter:

  1. Run the engine until it reaches normal operating temperature.
  3. Jack up the front of the car and support it on safety stands.
  5. Slide a drain pan of at least 6 quarts capacity under the oil pan.
  7. Loosen the drain plug.Put on a pair of gloves and turn the drain plug out by hand By keeping an inward pressure on the plug as you unscrew it, oil won't escape past the threads and you can remove it without being burned by hot oil.

When you are ready to release the plug, pull it away from the drain hole quickly, to avoid being burned by the hot oil.

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Fig. Fig. 4: Loosen the drain plug

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Fig. Fig. 5: Unscrew the drain plug by hand and let oil drain completely

  1. Allow the oil to drain completely and then install the drain plug. Don't overtighten the plug, or you'll be buying a new pan or a trick replacement plug for stripped threads.
  3. Using a strap wrench, remove the oil filter. Keep in mind that it's holding about one quart of dirty, hot oil.
  5. Empty the old filter into the drain pan and dispose of the filter.
  7. Using a clean rag, wipe off the filter adapter on the engine block. Be sure that the rag doesn't leave any lint which could clog an oil passage.
  9. Coat the rubber gasket on the filter with fresh oil. Spin it onto the engine by hand; when the gasket touches the adapter surface, give it another 1 / 2 - 3 / 4 turn. No more, or you'll squash the gasket and it may leak.
  11. Recheck that the drain plug and oil filter are properly tightened. Remove the oil pan and lower the vehicle.
  13. Locate and remove the oil filler cap and place a funnel in the filler opening.
  15. Refer to the capacities chart in this section for your vehicles specified amount of engine oil.
  17. Refill the engine with the correct amount and