2003–2007 Cadillac CTS

2003-2007 Cadillac CTS — Oil and Filter Change

By Ray Delgado ✓ Certified Mechanic · Published Sep 24, 2026 · Updated Oct 14, 2026

🔧 Easy 30–45 minutes $44 DIY

Save $130 by doing it yourself! Shop cost: $174

Quick answer: Oil and Filter Change on a 2003–2007 Cadillac CTS is rated Easy and takes about 30–45 minutes. You'll need 6 tools for this job, and parts cost about $44. This guide walks you through the full job step by step, including the mistakes to avoid.

Quick Video Tutorial

Parts You Need

Total Cost

$44.00

Oil spec 3.6L LY7 V6

Capacity 6.0 qt with filter Viscosity 5W-30 (alt: 10W-30)

Part Name	Part Number	Price	Buy
5W-30 engine oil (6 quarts)	—	$35.00	Amazon
Cartridge oil filter with O-ring	—	$9.00	Amazon

About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.

💡 Pro tip: Order all parts at once to save on shipping

Step-by-Step Instructions

Follow these steps carefully

Warm the engine and secure the car

Let the CTS idle for 2–3 minutes to thin the oil, then park on a level surface and set the parking brake. The first-generation CTS needs about 6 quarts of 5W-30. Open the hood.

Remove the engine cover and oil cap

Pull the plastic engine cover straight up off its mounting studs to access the top of the engine. Twist off the oil fill cap to vent the crankcase for faster draining. Set the cover somewhere clean — its underside collects grime you do not want in the engine.

🔧 Mechanic's note — Ray Delgado

Do yourself a favor like I do: I set the cover somewhere clean — I've seen grime from the underside drop straight into the engine.

Drain the oil from underneath

Raise the front on ramps or jack stands and locate the drain plug on the oil pan. Place the drain pan underneath, loosen the plug with a wrench, and finish by hand. Let it drain for 10 minutes until the stream becomes occasional drips.

Replace the top-side cartridge filter

Unscrew the cap with a filter socket, lift out the old paper element, and wipe the housing. Install the new element, lubricate the fresh O-ring with clean oil, and thread the cap back on snugly — do not overtighten the plastic.

🔧 Mechanic's note — Ray Delgado

Trust me on this one: Install the new element, lubricate the fresh O-ring with clean oil, and thread the cap back on snugly — do not overtighten the plastic.

Reinstall the plug and add oil

Thread the drain plug back in by hand and snug it with the wrench. Lower the car if raised. Pour in 6 quarts of 5W-30 through the fill tube, then reinstall the fill cap and press the engine cover back onto its studs.

Check the level and leaks

Start the engine for 30 seconds, shut it off, wait 2 minutes, and confirm the dipstick reads full. Look underneath for leaks at the plug.

Recycle the old oil and filter

Seal the used oil in containers and bag the old cartridge for the recycling drop-off. Most parts stores take both free of charge. Record the mileage — plan the next change at 5,000–7,500 miles depending on oil type and driving conditions.