GM Celebrity/Century/Ciera/6000 1982-1996 Repair Guide

Fuel and Engine Oil Recommendations

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FUEL RECOMMENDATIONS



Gasoline

All cars covered by this information must use unleaded fuel. The use of leaded fuel will plug the catalyst rendering it imperative, and will increase the exhaust back pressure to the point where engine output will be severely reduced. The minimum octane for all engines is 87 RON. All unleaded fuels sold in the U.S. and Canada are required to meet this minimum octane rating.

Use of a fuel too low in octane (a measurement of anti-knock quality) will result in spark knock. Since many factors affect operating efficiency, such as altitude, terrain, air temperature and humidity, knocking may result even though the recommended fuel is being used. If persistent knocking occurs, it may be necessary to switch to a slightly higher grade of unleaded gasoline. Continuous or heavy knocking may result in serious engine damage, for which the manufacturer is not responsible.

Your car's engine fuel requirement can change with time, due to carbon buildup, which changes the compression ratio. If your car's engine knocks, pings, or runs on, switch to a higher grade of fuel, if possible, and check the ignition timing. Sometimes changing brands of gasoline will cure the problem. If it is necessary to retard timing from specifications, don't change it more than a few degrees. Retarded timing will reduce power output and fuel mileage, and will increase engine temperature.

Diesel

WARNING
Failure to use specified fuels will result in engine damage for which the manufacturer is not responsible. Use of fuel additives is NOT recommended.

At any outside temperature above 20°F (&ndash7°C), Number 2-D diesel fuel should be used, since it will give better fuel economy then Number 1-D. When the outside temperature is below 20°F (&ndash7°C), use either Number 1-D fuel (preferred if available) or a blended Number 2-D. The blended Number 2-D has 1-D fuel in it, but will usually be called just Number 2-D. Check with the service station operator to be sure you get the proper fuel.

Diesel fuel may foam during filling, which is normal. The foam may cause the automatic pump nozzle to turn off before the tank is actually filled. The foaming effect can be reduced by slowing the fill rate.

OPERATING IN COLD WEATHER

All types of diesel fuel have a certain paraffin content. The paraffin components are high in energy content and help to improve fuel economy. Below about 20°F (&ndash7°C), the trouble with paraffin begins. At this temperature, the paraffin components begin turning to wax flakes. Depending upon the temperature, the wax flakes can block either or both of the two fuel filters (tank or engine) and stop fuel from reaching the engine.

Since Number 2-D fuel has more paraffin than Number 1-D (or blended Number 2-D), Number 2-D would be more apt to cause waxing problems (See Fuel Recommendations).

If the fuel tank filter plugs due to waxing, a check valve inside of the fuel tank will open and allow fuel to flow to the engine. Because of the check valve location, not all of the fuel in the tank can be used if the filter remains clogged (check valve remains open). About 4 gallons of fuel will remain in the tank when you run out of fuel. When driving in temperatures below 20°F (&ndash7°°C), be sure to keep the tank more than 1 / 4 full to help prevent running out of fuel if the filter plugs.

If equipped, the fuel line heater should be used when temperatures are expected to be below 10°F (&ndash12°C) and you have Number 2-D fuel in the tank.

WATER IN THE FUEL

Diesel fuel should be purchased from a reputable dealer, since the majority of the water found in a diesel fuel system gets into the system during refueling. Water can cause extensive (and expensive) damage to the diesel fuel system.

This car has a water separator system in the fuel tank and a Water-In-Fuel indicator on the instrument panel. The indicator is designed to illuminate when starting the engine (as a bulb check), or when water is detected in the tank. If the light comes on at any other time, there is probably a fault in the detector circuit. If the engine loses power and begins to run rough without the detector light on, there is probably water in the system. Both the fuel system and the detector circuit should be checked.

If the indicator light comes on immediately after refueling, a large amount of water was pumped into the tank, DON'T run the engine; the fuel system must be purged right away.

If the indicator lights after braking, cornering, etc., a moderate amount of water is in the system. In this case, the water should be removed within one or two days.

OIL RECOMMENDATIONS



Gasoline Engine

See Figures 1, 2 and 3

Under normal conditions, the engine oil and the filter should be changed at the first 7500 miles (12,000 km) or once a year whichever comes first. GM recommends that the oil filter be changed at every other oil change thereafter. For the small price of an oil filter, it's 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.



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Fig. Fig. 1: Oil viscosity selection chart - vehicles since 1987 are designed to use 5W-30 all year

Under severe conditions, such as:



Driving in dusty areas
 
Trailer towing
 
Frequent idling or idling for extended periods
 
Frequently driving short distances - 4 miles (6 km) or so-in freezing weather
 

The engine oil and filter should be changed every 3 months or 3000 miles (4800 km), whichever comes first. If dust storms are ever encountered in your area, change the oil and filter as soon as possible after the storm.



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Fig. Fig. 2: Gasoline oil selection chart

The American Petroleum Institute (API) designation (printed on the oil container) indicates the classification of engine oil for use under certain operating conditions. Oils having an API service designation of SG should be used in your car. The SG rating designates the highest quality oil meant for passenger car usage. It is okay to use an SG oil having a combination rating such as SG/CC or SG/CD for gasoline powered engines. In addition, GM recommends the use of SG/Energy Conserving oil. Oils labeled, Energy Conserving (or Saving); Fuel (Gas or Gasoline) Saving, etc., are recommended due to their superior lubricating qualities (less friction = easier and more efficient engine operation) and fuel saving characteristics. Use of engine oil additives is not recommended, because if the correct oil is purchased to begin with, the additives will be of no value.

Use of engine oils without an SG rating, or failing to change the oil and filter at the recommended intervals will cause excessive engine wear and could affect your warranty.



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Fig. Fig. 3: Look for one of these labels on your oil containers to ensure what is recommended

Diesel Engines

See Figure 4

The engine oil requirements for diesel engines are more stringent than those for gasoline engines, since contaminant build-up in the engine oil occurs much faster in the diesel engine. Also, the diesel contaminants are more damaging to the engine oil.



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Fig. Fig. 4: Diesel engine oil selection chart

Under normal operating conditions, the engine oil and filter MUST be changed every 5000 miles (8000 km), regardless of the time period involved.

Under severe operating conditions, such as those mentioned previously under Gasoline Engines, the oil and filter must be changed every 2500 miles (4000 km) or 3 months, whichever comes first.

In the diesel equipped car, ONLY an engine oil having one of the two following API designations should be used: SG/CC or SG/CD. Period! Don't use any other type of oil.


CAUTION
Failure to use an SG/CC or SG/CD oil will result in excessive engine wear and will probably void the engine warranty. Failure to change the oil and filter at the recommended intervals will have the same results.

In diesel engines, the use of oil in regard to its viscosity is limited. With a diesel, you only have three choices: 10W-30, 15W-40, or straight 30W. Refer to the accompanying chart to choose the engine oil viscosity according to the expected outside air temperature.

OIL LEVEL CHECK



See Figures 5, 6, 7 and 8

The engine oil level may be checked either when the engine is cold or warm, though the latter is preferred. If you check the level while the engine is cold, DO NOT start the engine first, since the cold oil won't drain back to the engine oil pan fast enough to give an accurate reading. Even when the engine is warm, wait a couple of minutes after turning it off to let the oil drain back to the pan.

  1. Raise the hood, pull the dipstick out and wipe it clean.
  2.  
  3. Reinsert the dipstick, being sure that you push it back in completely.
  4.  
  5. Pull the dipstick back out, hold it horizontally, and check the level at the end of the dipstick. Some dipsticks are marked with ADD and FULL lines, others with ADD 1 QT and OPERATING RANGE. In either case, the level must be above the ADD line. Reinsert the dipstick completely.
  6.  
  7. If oil must be added, it can be poured in through the rocker (valve) cover after removing the filler cap on the cover. Recheck the level a few minutes after adding oil.
  8.  
  9. Be sure that the dipstick and oil filler cap are installed before closing the hood.
  10.  

OIL & FILTER CHANGE



Screw-on Oil Filter

See Figures 9, 10, 11, 12 and 13

  1. Drive the car until the engine is at normal operating temperature. A run to the parts store for oil and a filter should accomplish this. If the engine is not hot when the oil is changed, most of the acids and contaminants will remain inside the engine.
  2.  



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Fig. Fig. 5: Remove the oil dipstick and wipe clean



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Fig. Fig. 6: When checking the oil level it should appear to be clean, not dark in color or thick. The level should be between the add and full marks



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Fig. Fig. 7: Turn and remove the oil filler cap



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Fig. Fig. 8: Insert a funnel into the valve cover and add the appropriate amount of engine oil needed

  1. Raise and support the front of the vehicle safely on jackstands to access the oil filter.
  2.  
  3. Slide a pan of at least six quarts capacity under the oil pan.
  4.  
  5. Remove the drain plug from the engine oil pan, after wiping the plug area clean. The drain plug is the bolt inserted at an angle into the lowest point of the oil pan.
  6.  
  7. Use a rag to protect your hands from the hot plug.
  8.  
  9. The oil from the engine will be HOT. It will probably not be possible to hold onto the drain plug. You may have to let it fall into the pan and fish it out later. Allow all the oil to drain completely. This will take a few minutes.
  10.  



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Fig. Fig. 9: Make sure you have a pan ready, loosen the drain plug with a wrench, then place the plug into the drain pan

  1. Wipe off the drain plug, removing any traces of metal particles. Check the condition of the plastic drain plug gasket. If it is cracked or distorted in any way, replace it. Reinstall the drain plug and gasket. Tighten the drain plug snugly.
  2.  



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Fig. Fig. 10: Install the plug and gasket snugly

  1. The oil filter for the V6 gasoline engine is right up front, just behind the radiator. The four cylinder oil filter is at the back of the engine, it is impossible to reach it from above. It is almost as inaccessible from below. It may be easiest to remove the right front wheel and reach through the fender opening to get at the four cylinder oil filter. The oil filter of the diesel V6 engine is located on the passenger side face of the engine block. Use an oil strap wrench to loosen the oil filter; these are available at auto parts stores. It is recommended that you purchase one with as thin a strap as possible, to get into tight areas. Place the drain pan on the ground, under the filter. Unscrew and discard the old filter. It will be VERY HOT, so be careful.
  2.  



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Fig. Fig. 11: Using a wrench loosen and remove the oil filter. Don't forget there is still a small amount of oil inside the filter

  1. If the oil filter is on so tightly that it collapses under pressure from the wrench, drive a long punch or a nail through it, across the diameter and as close to the base as possible, and use this as a lever to unscrew it. Make sure you are turning it counterclockwise.
  2.  
  3. Clean off the oil filter mounting surface with a rag. Apply a thin film of clean engine oil to the new filter gasket.
  4.  



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Fig. Fig. 12: Before installing a new oil filter, coat the rubber gasket with clean oil

  1. Screw the filter on by hand until the gasket makes contact. Then tighten it by hand an additional 1 / 2 - 3 / 4 of a turn. Do not overtighten.
  2.  



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Fig. Fig. 13: Using your hands install and tighten the filter onto the car

  1. Remove the filler cap on the rocker (valve) cover, after wiping the area clean.
  2.  
  3. Add the correct number of quarts of oil specified in the Capacities chart. If you don't have an oil can spout, you will need a funnel. Be certain you do not overfill the engine, which can cause serious damage. Replace the cap.
  4.  
  5. Check the oil level on the dipstick. It is normal for the level to be a bit above the full mark. Start the engine and allow it to idle for a few minutes.
  6.  


CAUTION
Do not run the engine above idle speed until it has built up oil pressure, indicated when the oil light goes out.

  1. Shut off the engine, allow the oil to drain for a minute, and check the oil level.
  2.  
  3. Check around the filter and drain plug for any leaks.
  4.  

Cartridge Oil Filter

See Figure 4

This cartridge type filter is found on some of the mid - model year 2.5L engines.

  1. Drive the car until the engine is at normal operating temperature. A run to the parts store for oil and a filter should accomplish this. If the engine is not hot when the oil is changed, most of the acids and contaminants will remain inside the engine.
  2.  
  3. Raise the car and support on jackstands.
  4.  
  5. Remove the oil pan drain plug.
  6.  
  7. Drain the oil into a drain pan.
  8.  



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Fig. Fig. 14: Cartridge type oil filter

  1. Slowly turn the plug to begin removal and pull downwards.
  2.  

Be sure to stand clear of the flowing oil from this next step.

  1. With a pair of pliers, applied to the tab/boss, remove the filter.
  2.  
  3. Make sure the O-ring/gasket was removed with the filter; if not remove it.
  4.  

To install:
  1. Coat the O-ring/gasket on the end of the filter with clean engine oil.
  2.  
  3. Press the filter into position in the housing by hand.
  4.  
  5. Make sure the filter is fully seated.
  6.  
  7. Check the oil filter O-ring/gasket for any damage and replace it, if necessary. Lube with oil the gasket and install the drain plug.
  8.  
  9. Tighten the plug 1 / 4 turn after gasket contacts, then tighten another 1 / 4 turn.
  10.  
  11. Lower the car, fill engine with proper amount of oil and check for leaks.
  12.  

After completing this job, you will have several quarts of oil to dispose of. The best thing to do with it is to funnel it into old plastic milk containers or bleach bottles. Then, you can locate a service station with a recycling barrel.

 
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