Used Buick Enclave 2nd Gen (2018-2024): Buyer's Guide

The 2018, 2019, and 2020 Buick Enclaves left the factory with the wrong transmission fluid. General Motors issued TSBs to address it, but if the dealer or prior owner never did the flush, that shudder at 40 mph is still there, waiting for you on the test drive. That's a $200 fix if you catch it early. It's a full transmission rebuild if you don't.

The 2nd gen Enclave (2018-2024) is a legitimate three-row SUV with a usable third row, a smooth V6, and a quiet cabin that punches above its price class on the used market. It shares a platform with the Chevrolet Traverse and GMC Acadia, which means documented issues carry across all three. Buy smart and you get a comfortable family hauler. Buy blind and you inherit someone else's deferred maintenance on a $720-per-year repair bill.

This guide covers what separates a solid 2nd gen Enclave from a problem vehicle, year by year.

This Generation at a Glance

The 2nd gen Buick Enclave launched for 2018 on GM's C1XX platform, shared with the Chevrolet Traverse and GMC Acadia. It ran through the 2024 model year before the 3rd gen (2025+) arrived with a turbocharged 2.5L four-cylinder. Every 2018-2024 Enclave uses the same engine, same basic structure, and the same 9-speed transmission throughout its run.

Key within-generation changes:

• 2018-2020: Twin-clutch AWD system available on Premium and Avenir trims; incorrect factory transmission fluid on 2018s
• 2021: Conventional AWD replaces twin-clutch across all trims; transmission software matured; fewer complaints
• 2022: Mid-cycle refresh with new exterior, push-button gear selector, wireless Apple CarPlay and Android Auto standard, full ADAS suite standard across all trims
• 2023-2024: Minor tech updates; Consumer Reports rates 2023 as "much more reliable than average"

The 2024 is the final year of the 2nd gen. The 2025 is a different vehicle entirely — smaller turbo four, different platform, different ownership profile.

FWD improves city driving by about 2 mpg. AWD owners report real-world highway figures of 24-28 mpg at 65-70 mph. See full year listings at /market/buick/enclave.

Powertrain and Drivetrain Breakdown

The 3.6L LGX V6: The Engine You're Buying

Every 2nd gen Enclave uses GM's LGX 3.6L V6, a natural-aspirated direct-injection engine rated at 310 hp and 266 lb-ft of torque. The LGX is the 4th evolution of GM's 3.6L family, and it's meaningfully better than the earlier LLT and LFX versions that earned the 3.6L its timing chain reputation.

The LGX does not have the catastrophic timing chain stretch pattern that plagued 2008-2017 Enclaves. That problem was largely specific to the older engine variants. When you read online about Enclave timing chains, most of those threads predate 2018.

What the LGX does have: oil consumption. GM specifies up to one quart per 2,000 miles as acceptable. Most owners never hit that mark, but some 2020-2021 owners report losing 2.5-3.5 quarts between oil changes. If the oil change history is sparse or overdue, the camshaft actuators, which need consistent oil pressure to function, may have been running dirty. Failed actuators show up as rough idle and P0010/P0011/P0014 codes. Repair: $400-$800 per actuator.

The engine's known expensive maintenance items: water pump (typically fails at 80k-120k miles, $600-$900 parts and labor), and spark plugs at the 60k interval ($200-$350). Neither is catastrophic, but both are negotiating points on higher-mileage units.

Engine inspection checklist: Check the oil dipstick before the test drive (cold start reveals much). If the oil is black and gritty at under 5,000 miles since the last change, that engine has been run hard on degraded oil. Ask for the maintenance record. If it doesn't exist, price in two oil changes and a fresh fuel system check.

The 9-Speed Automatic: Best in 2021+, Risky in 2018

The GM 9T65 nine-speed transmission is in every 2nd gen Enclave. The transmission itself isn't fundamentally flawed. The 2018-2020 problem traces to one specific cause: GM's factory fill used an incorrect transmission fluid that degraded quickly, causing the torque converter clutch to shudder at 35-50 mph under light throttle.

TSB 18-NA-091 addressed the issue for 2018 models with a TCM software update and full transmission fluid flush. PIP5608C addressed 2019 models. Recall 20V668 covered a separate but related issue: missing bolts on the start/stop accumulator endcap could leak transmission fluid onto hot engine components, creating a fire risk. The recall affected 2018-2020 Enclaves.

Forum consensus on EnclaveForum.net going back to 2018 is consistent: if the flush was done, the shudder resolves and the transmission behaves normally. If it wasn't done, the shudder persists and can progress to full torque converter failure over time.

By 2021, GM had the fluid chemistry and TCM calibration sorted. Owners on EnclaveForum.net consistently describe the 2021+ transmission as smooth and seamless. The J.D. Power reliability score for the 2021 Enclave was 84/100, the highest in the upper midsize SUV segment that year.

What to check on any 2018-2020: During the test drive, hold light throttle at 40-45 mph. A rhythmic vibration through the seat and floorboards that follows engine RPM is the TCC shudder. If present, ask for proof that the TSB flush was completed. If no service records exist, a flush costs $150-$250 and should be considered mandatory pre-purchase maintenance.

AWD: Two Systems, One Name

The 2nd gen Enclave offered two distinct AWD systems that both go by "AWD" in listings. They are not the same thing.

2018-2020 Twin-Clutch AWD (Premium and Avenir trims only): GM's electronic twin-clutch positraction system (RPO code G99) could actively distribute torque between rear wheels, not just between front and rear. It improved cornering grip and wet-weather traction noticeably. It was available only on Premium and Avenir trims with AWD. Base Essence AWD models did not receive it.

2021-2024 Conventional AWD (all trims): GM quietly removed the twin-clutch system for 2021, citing complexity. All 2021-2024 AWD models use a conventional rear-differential setup with no torque vectoring. It's simpler and more reliable, but not as capable in challenging conditions.

If you specifically want the twin-clutch system for winter driving, you need a 2018-2020 Premium or Avenir with AWD. Verify the RPO sticker in the glovebox shows G99. If you just need competent AWD for light snow and rain, the 2021+ conventional system handles it without fuss.

A note for 2026: GM is actively investigating an AWD fault on the 3rd gen C1XX platform (2024-2026 Traverse, Acadia, 2025-2026 Enclave) that triggers "Service All Wheel Drive" warnings. That investigation does not apply to the 2018-2024 2nd gen Enclave covered in this guide.

Trim-Specific Notes

The 2nd gen Enclave ran three core trims from 2018-2024, with a Sport Touring package added at the 2022 refresh.

Essence (base): Leather, heated front seats, 8-inch touchscreen, standard 7-passenger configuration. Gets you in the vehicle without drama. No ventilated seats, no Bose, no HUD. From 2022: wireless CarPlay/Android Auto, full ADAS suite.

Premium: The practical sweet spot. Adds ventilated and heated front seats, Bose 10-speaker audio, head-up display, surround-view camera, heated second-row seats, power-folding third row, wireless charging, and panoramic sunroof standard. This trim gets the most second-hand recommendation from long-term owners, because it has the features that matter daily without the Avenir price premium.

Avenir: Top trim with distinctive Avenir-exclusive exterior (waterfall grille, unique wheels, badging), upgraded Pelle Lusso leather seating, power side-step running boards, and optional premium ride suspension with continuously variable damping. The optional suspension improves ride quality over rough pavement noticeably.

One thing to know about the Avenir's optional premium suspension: if it's equipped, factor in potential failure. The continuously variable dampers are expensive to replace ($1,500-$2,500 per corner). For most buyers, the coil-spring suspension on Essence and Premium delivers 90% of the ride quality for none of the risk.

Sport Touring Package (2022+): Added to the Essence trim with the 2022 refresh. Blackout grille, 20-inch sport wheels, body-color exterior trim. Cosmetic only. No mechanical differences. Worth a small premium on the used market if you like the aggressive look.

Which Model Years to Target

The 2021 is the sweet spot for most buyers. The transmission software and fluid chemistry were sorted, the J.D. Power score peaked, and the price-per-feature ratio is favorable compared to 2022+. The conventional AWD change in 2021 is a net positive in reliability terms for buyers who don't need torque vectoring.

The 2020 is polarizing. Some sources call it the "best year" based on reliability surveys. Six NHTSA recalls tell a different story from a safety standpoint. The issues were real: a cracked frame rail that reduced crash protection, an airbag diffuser that could separate during deployment, a fuel pump that could stall the engine without warning. Every one of those recalls is a dealer-level fix at no cost — but every one needs to be verified before you buy. A 2020 with clean recall history is a solid vehicle. A 2020 with open recalls is not.

The 2018 needs homework. More NHTSA complaints than any other 2nd gen year. Most stem from the transmission fluid issue, which has a $200 fix. But if that fix wasn't done, the clock on torque converter wear has been running for 6-8 years. Pull the service history. If transmission service isn't documented, either negotiate down to cover it or walk.

Pre-Purchase Inspection Checklist

Run the VIN through /tools/recall-lookup before you go to the test drive. Know which recalls were filed against that specific vehicle and verify dealer completion in the service paperwork.

Transmission (2018-2020):

• During test drive at 35-50 mph under light throttle, note any rhythmic vibration through the seat. That is TCC shudder.
• Ask specifically whether TSB 18-NA-091 (2018) or PIP5608C (2019) was performed. Look for it in the service record.
• For any 2018-2020, verify NHTSA Recall 20V668 (start/stop accumulator) was completed.

Engine:

• Check oil level and quality cold. Add-a-quart between changes is within GM spec, but chronic low oil means inspect the camshaft actuators.
• Look for any oil seepage around the timing cover, valve covers, or oil pan. Light seepage is normal past 80k miles. Active leaks need addressing.

Air Conditioning:

• On a warm day, run the AC on maximum for 10 full minutes with the blower on high.
• Listen for a clunk or groan at startup (seized or failing compressor).
• If the air does not get noticeably cold within 3-4 minutes, the AC system has a problem. Budget $800-$1,200 for compressor replacement, more if refrigerant lines are involved.

Panoramic Sunroof (all Avenir, Premium, and most models with panoramic roof):

• Fully open the sunroof and shine a flashlight along the channel at each corner.
• Gently pour a small amount of water into the front and rear channels and watch for it to drain freely through the drain tubes.
• Inspect the headliner for brown staining, warping, or water damage near the A and D pillars. Stains mean the drains have clogged and leaked into the cabin.
• Clogged drains are a $100-$200 shop repair. Headliner replacement runs $600-$1,500.

AWD System:

• On gravel or loose pavement, make a tight circle at low speed. You should feel all four wheels pulling evenly. Clunking or grinding from the rear suggests a rear differential or coupling issue.
• For 2018-2020 Premium/Avenir AWD: confirm G99 (twin-clutch) on the RPO sticker (glovebox door), if that system matters to you.

Infotainment and Electronics:

• Power on the vehicle and immediately check the infotainment screen. Blank screens or a blue screen at startup are documented across this generation.
• Test the rear camera, blind-spot monitor, and OnStar connectivity.
• On 2021-2022 models, verify airbag-related recalls were completed: roof rail airbag connector and (for 2021) airbag calibration software.

Running Costs

AC compressor: Budget this as an expected cost on any 2nd gen with 60k+ miles. $800-$1,200 parts and labor is the typical repair. Some owners have needed the full refrigerant line system serviced alongside it, pushing the total to $1,500-$2,000. It is not a question of if on high-mileage examples — it is when.

Transmission service: Any 2018-2020 without a documented flush should have one done immediately. $150-$250. This is cheap insurance for a $3,000+ transmission rebuild.

FAQ

Is the 2nd gen Buick Enclave reliable? It's average to slightly below average for the segment, with a RepairPal annual repair cost of $720 compared to a $652 segment average. The worst years in the generation (2018, 2020) had specific fixable issues. A well-maintained 2021 or later with clean service history is a genuinely solid vehicle that owners report running past 200,000 miles.

What is the best year for the 2nd gen Buick Enclave? The 2021 scores highest on J.D. Power (84/100, top in segment), has a matured transmission, and carries fewer documented problems than 2018-2020. The 2022 is the pick if you need wireless CarPlay, Android Auto, and a modern ADAS suite standard on all trims.

Does the Buick Enclave have a timing chain problem? The 2008-2017 Enclaves (1st gen, LLT/LFX engines) had documented timing chain stretch. The 2018-2024 models use the newer LGX engine, which does not have the same timing chain pattern. Regular oil changes with dexos1 full synthetic prevent most LGX engine concerns.

What does the Buick Enclave 9-speed transmission shudder feel like? A rhythmic buzz or vibration through the seat and floorboard at 35-50 mph under light throttle. It comes from the torque converter clutch engaging and slipping due to contaminated fluid. It is distinct from normal road noise. The fix is a transmission fluid flush, documented under TSB 18-NA-091 (2018 models) and PIP5608C (2019 models).

How long does the AC compressor last on a Buick Enclave? Most owners see failure somewhere between 60,000 and 90,000 miles. Some fail earlier. Repair is $800-$1,200 for the compressor alone. Forum threads on EnclaveForum.net and Edmunds owner reviews consistently flag this as an expected cost of ownership, not a one-off failure.

Bottom Line

Run every VIN through a recall check. On 2020 models specifically, verify all six NHTSA campaigns are closed, including the frame rail crack. The 2021 Buick Enclave with the conventional AWD and documented transmission service is the mechanical sweet spot of this generation. If you need wireless CarPlay and fully standard ADAS, step to the 2022 refresh.

The Enclave's strengths — quiet cabin, usable third row, strong V6 — age well. Its costs — AC compressor, sunroof drain maintenance, transmission fluid on early examples — are predictable. Predictable costs you can negotiate. Surprises you can't. Track price drops on specific trim and year combinations at usecarscout.com.

Data sourced from NHTSA recalls database, EPA fuel economy data, and real owner experiences from EnclaveForum.net, BuickForums.com, Edmunds owner reviews, and CarComplaints.com. See the full Buick Enclave market data for pricing and inventory.