2017-2019 Buick LaCrosse Parts Guide: What Owners Replace First

The LaCrosse 3rd Gen ran from 2017-2019 and is the last full-size Buick sedan. After enough of these come across the parts counter you start to see the same short list of components over and over. Here is what owners of this generation actually end up buying, and what to know before you order.

Interior

The usual tell is carpet that stays damp under a worn factory mat. How the vehicle gets used moves this interval more than the odometer does.

Common parts in this group: floor liners, carpet floor mats, console lids, seat covers, shift knobs.

Worth knowing: Genuine trim matches grain and color code, which universal parts never quite do.

Exhaust and Emissions

The usual tell is a check engine light that appears after fueling and clears itself. Heat is the accelerant on this one, which is why it shows up faster here than up north.

Common parts in this group: catalytic converters, oxygen sensors, DEF injectors, diesel particulate filters, EVAP purge valves.

Worth knowing: Catalytic converters are emissions-certified parts, and substrate loading is what the downstream oxygen sensor is judging.

Brakes

The usual tell is a squeal that shows up cold and disappears after two or three stops. Mileage is a rough guide here. Load, heat and road surface matter more.

Common parts in this group: brake pads, brake rotors, brake calipers, brake hoses, wheel speed sensors.

Worth knowing: Pad compound changes brake torque, and brake torque is one of the inputs the stability control system assumes it knows.

Drivetrain and Transfer Case

The usual tell is a four wheel drive light that flashes and never engages. Catch it early and it is a parts bill. Ignore it and it becomes a parts and labor bill.

Common parts in this group: transfer case encoder motors, front differential actuators, u-joints, CV axles, driveshaft center bearings.

Worth knowing: Transfer case shift motors and encoders are matched to the specific case, and the module reads their position directly.

Heating and Air Conditioning

The usual tell is a clicking or ticking behind the dash when you change temperature. How the vehicle gets used moves this interval more than the odometer does.

Common parts in this group: cabin air filters, blower motors, blower motor resistors, A/C compressors, condensers.

Worth knowing: R-1234yf systems on newer GM vehicles use different oils and fittings than older R-134a systems.

Ignition and Engine Management

The usual tell is a check engine light that flashes under load, which means raw fuel is going into the converter. Heat is the accelerant on this one, which is why it shows up faster here than up north.

Common parts in this group: spark plugs, ignition coils, camshaft position sensors, crankshaft position sensors, oxygen sensors.

Worth knowing: Coil primary resistance affects dwell, and the ECM is calibrated for the factory value.

Before You Order

Have the VIN ready. On a LaCrosse the same model year can carry two or three different engines and several suspension packages.
Check the SPID label in the glove box or console for your RPO codes.
Front and rear parts are rarely the same number, even when they look identical.
If the part is electrical, confirm the fit before you order. Electrical parts are not returnable at any GM dealer, including us.

Shops and fleets can set up wholesale pricing at gmpartsclub.com/wholesale. Everyone else can start at our Buick OEM parts catalog or search for LaCrosse parts.