GM Corvette 1963-1982 Repair Guide

Fluid Changes

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ENGINE OIL & FILTER



The mileage figures given in your owner manual are the Chevrolet recommended intervals for oil and filter changes assuming average driving. If your Corvette is being used under dusty, polluted, or off-road conditions, change the oil and filter sooner than specified. The same thing goes for cars driven in stop-and-go traffic or only for short distances.

Always drain the oil after the engine has been running long enough to bring it to operating temperature. Hot oil will flow easier and more contaminants will be removed along with the oil than if it were drained cold. You will need a large capacity drain pan, which you can purchase at any store which sells automotive parts. Another necessity is containers for the used oil. You will find that plastic bottles, such as those used for bleach or fabric softener, make excellent storage jugs. An ecologically desirable solution to the used oil disposal problem is to find a cooperative gas station owner who will allow you to dump your used oil into his tank.

Chevrolet recommends changing both the oil and filter during the first oil change and the filter every other oil change thereafter. For the small price of an oil filter, it cheap insurance to replace the filter at every oil change. One of the larger filter manufacturers points out in its advertisements that not changing the filter leaves one quart of dirty oil in the engine. This claim is true and should be kept in mind when changing your oil.

CHANGING YOUR OIL



See Figures 1 through 12

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Fig. Fig. 1: Using a wrench, loosen the oil pan drain plug ...



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Fig. Fig. 2: ... then quickly withdraw the plug and allow the oil to drain into a pan



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Fig. Fig. 3: Use a strap-type wrench to loosen the oil filter ...



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Fig. Fig. 4: ... then remove the filter by hand



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Fig. Fig. 5: The oil filler cap is usually located on the rocker arm (valve) cover-1979 Corvette shown



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Fig. Fig. 6: Fill the crankcase with the proper amount and grade of engine oil, then check the oil level



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Fig. Fig. 7: Before installing a new oil filter, lightly coat the rubber gasket with clean oil



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Fig. Fig. 8: Unfasten the automatic transmission pan retaining bolts



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Fig. Fig. 9: After the fluid has drained, completely remove the fluid pan



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Fig. Fig. 10: Unfasten the retaining screw ...



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Fig. Fig. 11: ... then remove the filter from the valve body



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Fig. Fig. 12: Replace any necessary gaskets, seals and/or O-rings

  1. Run the engine until it reaches normal operating temperature.
  2.  
  3. Jack up the front of the car and support it on safety stands.
  4.  
  5. Slide a drain pan of at least 6 quarts capacity under the oil pan.
  6.  
  7. Loosen the drain plug. Turn the plug out by hand. By keeping an inward pressure on the plug as you unscrew it, oil wont escape past the threads and you can remove it without being burned by hot oil.
  8.  

Dispose of waste oil properly; dont pollute the environment. Avoid prolonged skin contact with used oil either directly or from oil-saturated clothing.

  1. Allow the oil to drain completely and then install the drain plug. Dont overtighten the plug, or youll be buying a new pan or a trick replacement plug for damaged threads.
  2.  
  3. Using a strap wrench, remove the oil filter. Keep in mind that it holding about one quart of dirty, hot oil.
  4.  

1963-67 Corvettes use a cartridge type oil filter. On these models, loosen the center bolt on the filter housing and remove the housing along with the filter. If possible, replace the housing-to-block seal during installation and do not overtighten the housing bolt. Aftermarket adaptors are available to adapt the new style spin-on filters to earlier engines. Some prefer the convenience of a spin-on filter, though the cartridge type filter actually offers a greater filtering area.

  1. Empty the old filter into the drain pan and dispose of the filter.
  2.  
  3. Using a clean rag, wipe off the filter adapter on the engine block. Be sure that the rag doesnt leave any lint which could clog an oil passage.
  4.  
  5. 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 youll squash the gasket and it will leak.
  6.  
  7. Refill the engine with the correct amount of fresh oil. See the "Capacities" chart.
  8.  
  9. Crank the engine over several times and then start it. If the oil pressure gauge shows zero, shut the engine down and find out what wrong.
  10.  
  11. If the oil pressure is OK and there are no leaks, shut the engine off and lower the car.
  12.  
  13. Wait a few minutes and check the oil level. Add oil, as necessary, to bring the level up to Full.
  14.  

MANUAL TRANSMISSION



No intervals are specified for changing the transmission lubricant, but after extended heavy duty operation it may be a good idea. The vehicle should be on a level surface and the lubricant should be at operating temperature.

  1. Position the vehicle on a level surface.
  2.  
  3. Place a pan of sufficient capacity under the transmission drain plug.
  4.  
  5. Remove the upper (fill) plug to provide a vent opening.
  6.  
  7. Remove the lower (drain) plug and let the lubricant drain out.
  8.  
  9. Replace the drain plug.
  10.  
  11. Add lubricant with a suction gun or squeeze bulb. The correct lubricant is SAE 80W-90 GL-5 Gear Lubricant, or SAE 80W GL-5 for cold climates. Refer to the Capacities and Pressures Chart for the correct quantity.
  12.  

AUTOMATIC TRANSMISSION



The fluid should be drained while the transmission is warm.

  1. Using a jack, raise the front of the vehicle and support it safely with jackstands. If the transmission pan has no drain plug, visually check that you can gain access to all of the transmission pan bolts. If you can, proceed to step 8; if not, proceed to step 2.
  2.  
  3. Place a jack under the transmission with a block of wood (a piece of a 2X4 will do) between the jack and the transmission pan.
  4.  
  5. Raise the jack until the wood block contacts the transmission pan.
  6.  
  7. Remove the crossmember-to-transmission mount bolts and the crossmember-to-frame bolts.
  8.  
  9. Raise the transmission SLIGHTLY-just enough to take the weight of the transmission off of the crossmember.
  10.  
  11. Turn the crossmember sideways and remove it.
  12.  
  13. Place a jackstand close to the transmission tailshaft. Lower the jack until the transmission rests on the stand. Remove the jack and the wood block.
  14.  
  15. Place a drain pan under the transmission pan. If the pan has a drain plug, remove it and allow the fluid to drain.
  16.  
  17. If the pan does not have a drain plug, remove the pan bolts from one side of the pan and loosen the rest of the bolts. This will allow the pan to partially drain. Remove the remaining pan bolts and carefully lower the pan away from the transmission.
  18.  

If the transmission fluid is dark or has a burnt smell, transmission damage is indicated. Have the transmission checked professionally.


CAUTION
If the pan sticks, carefully tap sideways on the pan with a rubber mallet or a plastic hammer to break the pan loose. DO NOT dent the pan. Avoid prying the pan off-this can bend the pan or crack the transmission case.

  1. Empty the pan, remove the gasket material, and clean the pan with solvent (carburetor cleaner works well).
  2.  
  3. Remove any gasket material which may remain on the transmission case.
  4.  
  5. Remove the transmission filter from the valve body. The filter may have either a fibrous or screen filtering element and is retained by one or two fasteners.
  6.  
  7. Install a new filter using a new gasket or O-ring (TH400).
  8.  

If the transmission uses a filter having a fully exposed screen, it may be cleaned and re-used.

  1. Install the pan using a new gasket. Tighten the bolts to 12-14 ft. lbs. in a crisscross pattern. Recheck the bolt torque after all of the bolts have been tightened once.
  2.  
  3. Add either Dexron or Dexron II transmission fluid through the filler tube. See the Capacities Chart to determine the proper amount of fluid to be added.
  4.  


CAUTION
DO NOT OVERFILL the transmission; foaming of the fluid and subsequent transmission damage due to slippage will result.

  1. With the gearshift lever in PARK, start the engine and let it idle. Do not race the engine.
  2.  
  3. Move the gearshift lever through each position, holding the brakes. Return the lever to PARK, and check the fluid level with the engine idling. The level should be between the two dimples on the dipstick, about 1 / 4 in. below the ADD mark. Add fluid, if necessary.
  4.  
  5. Check the fluid level after the vehicle has been driven enough to thoroughly warm up the transmission. Details are given under Fluid Level Checks earlier in this information. If the transmission is overfilled, the excess must be drained off.
  6.  

REAR AXLE



Refer to the Maintenance Intervals chart for information on when to change the fluid.

  1. Run the vehicle so the lubricant reaches operating temperature.
  2.  
  3. Position a drain pan under the rear axle.
  4.  
  5. Remove the axle housing cover and gasket and drain the lubricant.
  6.  
  7. Clean the gasket sealing surfaces and install the cover with a new gasket.
  8.  
  9. Tighten the cover bolts in a crosswise pattern to 20 ft. lbs.
  10.  
  11. Add 4 oz. of rear axle lubricant additive (GM 1052358).
  12.  
  13. Use a suction gun or a squeeze bulb and refill the differential housing to a level within 3 / 8 " of the filler plug with rear axle lubricant (GM 1052271) or equivalent. (See the Capacities Chart).
  14.  
  15. Install the filler plug.
  16.  

COOLANT



Refer to the Cooling System information under Routine Maintenance. Observe the recommended specifications for aluminum, if necessary.

 
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