2021 Cadillac XT6 Problems: 7 Known Issues

On the 2020-2021 Cadillac XT6 3.6L V6 LGX, gM bulletin 21-NA-108 (which superseded PIP5257E) covers engine overheating with the cooling system contaminated by engine oil, and it lists the 2020-2021 Cadillac XT6 with the 3.6L LGX V6 among the affected applications. The failure is not a head gasket in the usual sense: pressurized oil from the main oil gallery migrates into a coolant water jacket through porosity or a thin-wall casting defect in the engine block. Because oil pressure is far higher than coolant pressure, oil pushes into the coolant rather than the other way round, and the surge tank and radiator fill with a thick brown oil-and-coolant emulsion that looks like a milkshake. That emulsion will not carry heat, so the engine overheats, and it plugs the radiator and heater core. GM bulletins 21-NA-147 and 22-NA-240 cover the related diagnosis of a coolant and/or oil leak with the malfunction indicator lamp on. This is engine-code specific — it is an LGX 3.6L casting issue and is not a claim about the 2.0L LSY turbo four also sold in the XT6.

On the 2020-2023 Cadillac XT6, xT6 owners report a "Steering Assist is Reduced — Drive with Care" or "Service Power Steering" message in the driver information center, usually with a noticeable increase in steering effort. GM bulletin 20-NA-215 covers this condition on XT5 and XT6 vehicles built between September 28 and October 22, 2020, and ties it to DTCs C0460 and/or C0545 stored in the power steering module. The XT6 uses a belt-drive electric rack with the motor and control module integrated into the steering gear; per the bulletin, internal components can make interference contact as the wheel turns, grounding and damaging internal electrical parts, which sets the code and the module deliberately cuts or reduces assist rather than allowing erratic assist. Steering is still mechanically connected — the car remains steerable — but effort rises sharply, which is most alarming at parking-lot speeds or in an evasive maneuver. Owners also describe a separate, milder version where assist fades after sustained low-speed maneuvering and returns once the system cools; that thermal derate is normal protection, not a failed rack, and it clears itself.

On the 2021 Cadillac XT6, if you own a 2021 Cadillac XT6, this one is worth a VIN check. GM recalled a limited group of 2021 XT6, XT5 and GMC Acadia vehicles because the fuel supply lines may have been improperly attached and seated at the factory. Lines that are not properly seated may loosen or separate, causing a fuel leak, which increases the risk of a fire. The whole campaign covers 572 vehicles across all of the models listed, so inclusion is the exception rather than the rule for the XT6 — but the potential outcome is serious enough that verifying by VIN is the right move rather than waiting to notice a problem. GM's internal recall number is N212335590, and owner letters were mailed July 1, 2021.

On the 2020-2021 Cadillac XT6, gM bulletin 19-NA-167 covers water leaking into the interior on the 2020-2021 Cadillac XT6 (alongside the 2017-2021 XT5 and GMC Acadia). Owners find wet carpet or headliner at the front and/or rear, on either side, typically after rain or a car wash. The cause is not the sunroof drains that owners and shops usually chase first: it is pinhole voids in the laser braze joint between the roof panel and the outer body ring, and in the seam sealer over it. The bulletin says the pinholes are most often found near the top of the windshield at the A-pillars, or near the top of the liftgate at the D-pillars. Water entering at the D-pillars runs down into the rear of the vehicle, and the bulletin specifically notes that on the XT6 the liftgate actuator may become noisy or inoperative as a result — so an electrical complaint at the tailgate is a symptom of the body leak, not a separate failure. Left alone, trapped water rots carpet padding, grows mold, and corrodes rear body connectors.

On the 2020-2021 Cadillac XT6, gM PIP5608F covers 2020-2021 XT6 vehicles with 9-speed transmissions RPO M3G or M3W when torque-converter clutch shudder occurs on re-apply after a shift at 40 mph or below. GM identifies possible excessive assembly lubricant in the fluid and requires confirmation with TCC slip data or the scan-tool command test.

On the 2020-2021 Cadillac XT6, if your 2020 or 2021 Cadillac XT6 was ordered with the optional Surround Vision feature, it may be part of NHTSA recall 22V709000. GM found that the coaxial cable connectors carrying the rearview camera signal may have been crimped improperly, and a faulty crimp can cause the rearview camera to fail outright or work only intermittently. The practical effect for an XT6 driver is a missing or unreliable rear image when reversing, which NHTSA notes reduces rear visibility and increases crash risk. XT6s without Surround Vision are not covered. The campaign as a whole spans 95,231 vehicles across all the models it includes - that number is for the entire campaign and says nothing about how many XT6s are involved. GM tracks the recall internally as N222378380 and mailed owner letters on January 18, 2023.

On the 2021-2023 Cadillac XT6, owners of 2021-2023 Cadillac XT6 vehicles built before the bulletin's VIN breakpoint report a grinding or groaning noise from the front brakes on the first few stops, particularly after the vehicle has sat overnight. It may feel like the ABS is active even though it is not. GM bulletin 21-NA-142 (current revision January 2025) says the cause may be the front disc brake pad material and has technicians check the pad stamp (GM9130 or GM9140). The same bulletin also covers the Buick Enclave, Cadillac XT5, Chevrolet Blazer and Traverse, and GMC Acadia within listed VIN ranges.