How to Change the Oil in a 2003 Cadillac CTS

Written by kyle mcbride
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How to Change the Oil in a 2003 Cadillac CTS
Motor oil lubricates the internal components of the CTS' engine. (Kurbelwelle image by martin filzwieser from

Cadillac equipped the 2003 model-year CTS with a deep-sump type oil pan and canister-type oil filter. A paper element that is housed by the oil filter canister provides oil filtration. The oil pump pressurises the oil, pushes it through the oil filter and returns it to the engine. Water, carbon flakes and metal salts build up over time and cause the viscosity of the oil to break down and lose much of its lubricating properties, necessitating regular maintenance in the form of engine oil and filter changes.

Skill level:

Things you need

  • Jack
  • 4 jack stands
  • Catch pan
  • Allen wrench set
  • Shop rag
  • Wrench set
  • Inch-pound torque wrench
  • Socket set
  • Foot-pound torque wrench
  • Engine oil, 5 quarts
  • Owner's manual

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  1. 1

    Park the CTS on level ground and allow the engine to cool.

  2. 2

    Lift the front and rear of the vehicle with a jack. Secure the vehicle on two sets of jack stands.

  3. 3

    Place a catch pan under the engine oil drain plug. Remove the drain plug with an Allen wrench. Allow the oil to drain from the engine. Wipe the plug with a clean shop rag and check for damage or deformities. Replace the plug if it is damaged.

  4. 4

    Place the drain pan under the oil filter canister. Remove the oil filter canister drain plug with a wrench. Drain the oil filter canister.

  5. 5

    Remove the filter cap from the bottom of the canister with a wrench. Pull the cap and filter out of the canister. Separate the filter element and the cap. Wipe the cap with a clean shop rag. Inspect the cap and cap O-ring for damage and replace if necessary.

  6. 6

    Install the oil filter canister drain plug and torque it to 89 inch-pounds with a 1/4-inch torque wrench and socket.

  7. 7

    Snap the new filter element into the filter cap. Grease the O-ring with some fresh engine oil. Push the element into the canister and torque the filter cap to 18 foot-pounds with a 3/8-inch torque wrench and socket.

  8. 8

    Insert the oil pan drain plug into the drain hole and torque it to 89 inch-pounds with a 1/4-inch torque wrench. Clean up any remaining oil around the drain plugs and the canister with a shop rag.

  9. 9

    Lift the vehicle with a jack and remove the jack stands. Lower the vehicle to the ground.

  10. 10

    Remove the oil filler cap. Add five U.S. quarts of the appropriate viscosity engine oil. Refer to the owner's manual for a temperature/oil viscosity chart. Replace the oil filler cap.

  11. 11

    Start the engine. Observe the engine oil pressure gauge until it registers oil pressure. Turn the engine off and check the drain plugs and canister for leaks. Check and top off the engine oil level as indicated by the dipstick.

Tips and warnings

  • Never get under a vehicle supported by the jack only. Support the weight of the CTS on jack stands.

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