I started to notice changes in performance around 75k miles. Seemed like performance was subpar compared to what was the norm. Seemed to lose some power. Minimal at first, more so just recently around 90k. Oil consumption was starting to accelerate at each oil change at 75k, 80k, 85k, 90k. To the point around 85k and 90k that I would not go over even 1 mile from the 5k threshold without changing…
2020 GMC Sierra engine problems
moderate 155 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
155
Recalls
0
Avg fix
$3,100
When does it fail?
Of the 155 engine complaints filed for the 2020 GMC Sierra, here's the actual mileage breakdown — failures cluster heaviest at 25,000-50,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Engine accounts for 36% of every owner complaint on file for this vehicle — the dominant problem area across 10 categories tracked.
Owners have filed 155 engine complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
The failure pattern owners describe
Owners of 2020 GMC Sierras describe sudden, catastrophic engine failures with no prior warning. The most common complaint is lifter collapse—hydraulic valve lifters fail, typically between 3,500 and 103,000 miles, often causing damage to the camshaft and pushrods. One owner experienced three separate lifter failures in the same truck within 100,000 miles, with a dealer Service Manager stating he would not trust the vehicle for long distances.
Rod bearings seizing up without notice is another recurring failure mode. Owners report driving at highway speed (65–70 mph) when the engine suddenly loses all power, forcing them to coast across traffic lanes to safety. One owner had bearings fail twice in his truck, then seize again on the replacement engine 35,000 miles later—three catastrophic failures total in meticulous maintenance records.
Excessive oil consumption is widespread. Owners report needing to add 1–3 quarts per 5,000-mile service interval despite using the recommended Dexos Gen 3 oil. Dealers cite Bulletin 01-06-01-011M claiming this is normal, leaving owners without recourse. Some owners link this and lifter failures to the Dynamic Fuel Management (DFM) system, with one dealer Service Manager confirming DFM is a design flaw combined with GM's low oil viscosity recommendation.
Many owners note the 2020 models are excluded from the current NHTSA Recall 24V-676 (covering 2021–2024 6.2L engines), despite having identical engines and experiencing identical failures. Repair costs typically range $5,400–$16,000, and owners report zero warranty coverage once mileage exceeds 60,000 miles. Several owners describe spending weeks without their vehicle while dealerships diagnose problems, with no loaner vehicles offered.
Same GMC Sierra engine reports on nearby years: 2018 · 2019 · 2021 · 2022 · 2023
Failure modes owners describe
Lifter collapse or failure
Hydraulic valve lifters collapse or fail, often causing damage to the camshaft and pushrods. Multiple complaints describe lifter failures recurring after repair, with some vehicles experiencing three or more failures.
When: Typically 3,500 to 103,000 miles; some within first 5,000 miles after purchase
Symptoms owners cite: Metallic ticking, knocking, or clicking noise from engine; Loss of power or reduced acceleration; Check engine light (P0305, P0016, P06DD diagnostic codes); Engine misfire; Rough idle or shaking on startup; Multiple warning lights (Service ESC, Service Parking Brake, steering assist reduced, traction off); Vehicle stalling or loss of propulsion
Codes mentioned: P0016, P0305, P06DD
Repairs/costs cited: Lifter replacement costs range from $1,600–$13,000+ depending on extent of damage; many complaints report repeated failures requiring multiple repairs or full engine replacement. Some owners cite dealer labor of $5,400–$6,500 for lifter and related work.
Recalls/TSBs owners mention: Bulletin 01-06-01-011M issued regarding oil consumption (owners report being told this consumption is 'normal'). TSB 22-NA-027 referenced for valve cover issues. 2021–2024 models with 6.2L engine subject to NHTSA Recall 24V-676 and Special Coverage N252508341 (limited to certain model years and engine configurations). 2020 models explicitly excluded from recall despite identical part numbers and engine design.
Rod bearing seizure or failure
Rod bearings spin, seize, or lock up, causing complete engine seizure and loss of propulsion without warning. Metallic debris found in oil pan in some cases.
When: Reported at 63,000 miles, 70,000 miles, and approximately 102,000 miles; some failures recur on replacement engines
Symptoms owners cite: Sudden complete loss of engine power while driving (often at highway speeds 65–70 mph); Loud knocking or popping noise from engine immediately before seizure; Engine refuses to restart; Heavy metal debris in oil pan; No prior warning lights or sounds in many cases
Codes mentioned: P0016
Repairs/costs cited: Engine replacement cost approximately $5,000–$16,275. One owner reports three separate bearing failures in the same vehicle over 65,000 miles of driving; replacement engines also experienced bearing failure (35,000 miles later). Dealers report finding spun rod bearings upon teardown.
Recalls/TSBs owners mention: Owners cite dealers blaming poor maintenance or 'bad oil,' though owners document regular oil changes and proper maintenance. No recall coverage; repairs out-of-pocket. One owner reports GM offering 10% discount on repair as 'goodwill' for vehicle out of warranty.
Camshaft damage (pitting, chrome flaking, lobe damage)
Camshaft chrome coating flakes or pits, causing lobe damage and lifter/pushrod failure. Often secondary damage following lifter failure, but also reported as primary failure.
When: Between 59,000 and 102,000 miles; some concurrent with or shortly after lifter repair
Symptoms owners cite: Metallic knocking or ticking noise; Loss of power; Check engine light; Engine misfire; Bent or damaged pushrods
Repairs/costs cited: Camshaft replacement cost $500–$2,000+ as part of larger engine rebuild (lifter + camshaft replacement $5,400–$13,000 total). One owner reports preemptively replacing camshaft and using solid lifters to eliminate DFM system after initial repair.
Recalls/TSBs owners mention: No specific recall for camshaft defects; covered under general engine failure claims. Dealers have acknowledged the issue as 'common' and linked to Dynamic Fuel Management (DFM) design.
Excessive oil consumption
Engine consumes or loses abnormally high amounts of oil between service intervals, requiring frequent top-offs. Owners report burning 1–3+ quarts per 5,000–6,000 miles, far exceeding manufacturer specification.
When: Reported from initial oil changes (first 6,000 miles) through 90,000+ miles
Symptoms owners cite: Low oil level warnings; White milky residue on oil cap; Burning oil smell; Smoke from exhaust or engine area; High oil consumption (1–3 quarts per service interval)
Repairs/costs cited: Owners perform dealer oil-consumption tests; no repair option offered. Owners report using Dexos Gen 3 (premium) oil as recommended but consumption persists. One owner replaced lifters, camshaft, and installed solid lifters + DFM disable, but oil consumption issue may remain.
Recalls/TSBs owners mention: Bulletin 01-06-01-011M cited by dealers claiming high oil consumption is 'normal' within manufacturer specifications. Dealers offer no remedy.
Engine seizure (sudden total loss of propulsion)
Engine suddenly stops running while driving, leaving vehicle without power. Engine may be locked tight and refuse to restart. Distinct from rod bearing failure in some cases.
When: Reported at 26 miles (towing situation post-purchase), 56,472 miles, 70,000 miles, 96,000+ miles; one case at approximately 250 miles (within days of purchase)
Symptoms owners cite: Complete loss of engine power without warning while driving; Blank instrument panel or loss of electrical function; Engine will not restart or restarts only after long delay; No sound or noise preceding seizure in most cases; Dash goes blank; no attempt from starter; Check engine light (varies)
Codes mentioned: P0016
Repairs/costs cited: Engine replacement cost $7,000–$16,275+ (remanufactured or new). One owner paid $12,653.97 for remanufactured long block; dealer charged double for 'core' retention and refused to allow owner to keep engine for evidence. Repairs not covered under warranty if mileage exceeded 60,000 miles.
Recalls/TSBs owners mention: Dealers initially claim inability to determine cause; some later attribute to 'bad oil' or bearing failure. One case (complaint #38) confirmed to be rod throwage, same as 2021–2024 recall issue. GM does not cover repairs outside warranty period despite known defect.
Dynamic Fuel Management (DFM) system malfunction
DFM system (which deactivates four cylinders at low load) causes all eight cylinders to shut down simultaneously or fails to reactivate cylinders, resulting in random misfire, loss of power, and drivability issues. Dealers and owners link DFM to lifter stress and oil consumption.
When: Reported from 50,000 to 91,000+ miles; some begin early in ownership
Symptoms owners cite: Random misfire and hesitation while driving; Momentary loss of power during acceleration; Rough idle with RPM dips; Transmission shift issues (hard shifting, judder); Check engine light (P0305, P0016 codes); All eight cylinders deactivating instead of four; Ticking or knocking during DFM cycling
Repairs/costs cited: Dealers perform software updates per TSB; many report update does not resolve issue. Owners have installed aftermarket DFM disablers, which resolve misfire but technically void warranty. One owner reports mechanic and dealer acknowledging DFM is a design flaw linked to lifter failure and low oil viscosity recommendation.
Recalls/TSBs owners mention: GM issued TSB (referenced as part of Bulletin 01-06-01-011M) recommending software update and low-viscosity oil (allegedly too thin for this application). Dealer Service Manager stated DFM design flaw is cause of lifter collapse. GM has not issued recall for DFM-related failures in 2020 models.
Severe oil leaks and loose oil filter
Oil filter comes loose or oil pan leaks, spilling large quantities of oil during operation. One complaint describes oil filter three turns loose after dealership service.
When: Reported at 90,000+ miles; one case immediately after oil change service at dealership
Symptoms owners cite: Large puddle of oil under vehicle after parking; Oil cap sitting improperly on air shelf instead of in filler tube; Oil filter loose (approximately 3 turns); Visible oil loss
Repairs/costs cited: Oil filter reinstalled or replaced at dealership; oil level restored. No documented engine damage in reported cases.
Recalls/TSBs owners mention: None documented; treated as service defect rather than design flaw.
Pushrod failure (bent or failed pushrods)
Pushrods bend or fail, causing loss of power, knocking noise, and potential catastrophic engine damage if breakage occurs.
When: Reported at highway speeds (approximately 65–70 mph); one case early in vehicle life
Symptoms owners cite: Loss of power while attempting to pass at highway speed; Loud knocking or popping noise from engine; Check engine light; Multiple warning lights
Codes mentioned: P0016
Repairs/costs cited: Pushrod repair cost not documented separately; typically part of engine rebuild or full replacement ($5,400–$13,000). One owner reports pushrod bending (not breaking) due to camshaft lobe pitting.
Recalls/TSBs owners mention: Diagnosis confirmed by GM dealer; issue linked to camshaft chrome flaking and defective design.
Multiple misfire and loss of power events
Vehicle displays numerous diagnostic trouble codes (40–45+ codes in some cases), loss of power warning, and multiple warning lights without clear root cause identified at dealership.
When: Reported at various mileages from low to high; one recent case (2025) at unspecified mileage
Symptoms owners cite: Check engine light (numerous codes); Loss of power warning message; Vehicle pulling back before accelerating; Increased fuel consumption; Reduced braking assist before stopping; Over 45 diagnostic trouble codes retrieved
Codes mentioned: Multiple (40–45+ codes in one case)
Repairs/costs cited: One owner retrieved 45+ codes from two separate diagnostic scanners (dealership and independent mechanic); recommended dealership service but no repair outcome documented yet.
Recalls/TSBs owners mention: None documented; case ongoing.
Coolant control valve failure (LM2 Duramax diesel)
Coolant control valve fails, triggering reduced engine power mode and limiting vehicle speed on highway.
When: Reported on 2020 model with LM2 Duramax diesel; mileage not specified
Symptoms owners cite: 'Reduced Engine Power' warning message on dashboard; Check engine light; Maximum speed limited to approximately 40 mph; Loss of power while climbing hill on interstate
Repairs/costs cited: Part on nationwide backorder; repair delayed indefinitely. Part replacement cost not documented.
Recalls/TSBs owners mention: GM issued Special Coverage N252508341 for 2021–2022 GMC Sierra 1500 LM2 Duramax models; 2020 models explicitly excluded despite identical part numbers and engine configuration.
Synthesized from 155 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 5 most recent
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving approximately 35 MPH, the vehicle lost automotive power with the check engine warning light illuminated and the message "Vehicle Might Lose Power" displayed. The vehicle remained at the residence, and the contact used a self-diagnostic tool to retrieve a fault code related to the coolant valve D. The contact determined…
Fuel management system caused a lifter to fail (stuck) which resulted in camshaft damage at 77,611 miles. GM refused to cover the repair, although there is a pending class action lawsuit against GM for this very issue. Truck was repaired at a GM dealership - Sunrise Collierville, TN. Repair costs was approximately $7,000. This occurred during a 2.5 hour road trip which put lives at risk. The…
In December of 2023 my 2020 GMC Sierra 1500 was driving down the freeway, experienced a jerking and low oil pressure. Pulled over and shut vehicle off and wouldn't turn back on, engine locked up. The vehicle received a brand new 6.2l replacement motor in April of 2024- $15k in parts and labor. This vehicle was not included in the recent recall, but obviously experienced a similar issue. This was…
Engine lost all power while driving highway speed. Vehicle towed to Cavender Chevrolet dealer in Boerne, TX. Dealer inspected and determined cam bearings damaged. Engine replaced with remanufactured engine.
Had engine trouble with your 2020 GMC Sierra?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2020 GMC Sierra?
It's a documented issue but not catastrophic. 155 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Across the 31 complaints that reported odometer mileage, most engine failures cluster between 40,000 and 121,000 miles, with the median around 76,000. A quarter of owners report trouble before 40,000; a quarter make it past 121,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2020/GMC/Sierra.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.