Is the 2020 Gmc SIERRA DENALI reliable?

The 2020 Gmc SIERRA DENALI has 10 complaints filed with NHTSA (0.5x the segment average). Our reliability verdict: excellent. Most common issue: ENGINE problems.

What are common problems with the 2020 Gmc SIERRA DENALI?

Top problems: ENGINE (6 complaints, avg repair $500); BRAKES (2 complaints, avg repair $500); ELECTRICAL (1 complaints, avg repair $500). Issues typically appear around 50K miles.

Are there any recalls on the 2020 Gmc SIERRA DENALI?

No recalls have been issued for the 2020 Gmc SIERRA DENALI.

How much does it cost to insure a 2020 Gmc SIERRA DENALI?

Estimated US average full-coverage insurance for the 2020 Gmc SIERRA DENALI is approximately $1,607/year (sedan-midsize class). Actual quotes vary heavily by state, driver age, driving record, and credit — see the interactive insurance estimator on this page for state-specific pricing.

2020 Gmc SIERRA DENALI

Problems, Recalls & Reliability Report

Excellent Reliability

Quick Summary

The 2020 Gmc SIERRA DENALI has 10 owner complaints filed with NHTSA — that's 0.5x the segment average of 19. The most common issue is engine problems (60% of all complaints), specifically: i noticed several spots of oil on my driveway, i then inspected the underside of the engine (l5p) and noticed oil dripping from several bolts and lines. my vehicle, a 2020 2500hd denali diesel, has only 2,200 miles on it from normal highway driving..

Total Complaints

Recalls Issued

—/5

Safety Stars

0.5x

vs Segment Avg

Known Problems(top 4 of 4)

ENGINE

6 complaints

60%

• I NOTICED SEVERAL SPOTS OF OIL ON MY DRIVEWAY, I THEN INSPECTED THE UNDERSIDE OF THE ENGINE (L5P) AND NOTICED OIL DRIPPING FROM SEVERAL BOLTS AND LINES. MY VEHICLE, A 2020 2500HD DENALI DIESEL, HAS ONLY 2,200 MILES ON IT FROM NORMAL HIGHWAY DRIVING.
• TWO ISSUES BROKEN VALVE SPRING CAUSED ENGINE TO SHUT DOWN, SECOND SERVICE BRAKE, BRAKE FAILURE LIGHT, SERVICE ESC, SERVICE TRAILER BRAKE MESSAGES CAUSING BRAKE FAILURE
• KNOCKING COMING FROM ENGINE - NOTICEABLE UNNECESSARY NOISE IN WHICH DEALER CAN NOT FIX THE PROBLEM

Typical onset: 50K miles Est. repair: $500

“I NOTICED SEVERAL SPOTS OF OIL ON MY DRIVEWAY, I THEN INSPECTED THE UNDERSIDE OF THE ENGINE (L5P) AND NOTICED OIL DRIPPING FROM SEVERAL BOLTS AND LINES. MY VEHICLE, A 2020 2500HD DENALI DIESEL, HAS ONLY 2,200 MILES ON IT FROM NORMAL HIGHWAY DRIVING.”

— NHTSA complaint filing

Estimated Insurance Cost for 2020 Gmc SIERRA DENALI

Estimate only, not a quote. Modeled from NAIC + HLDI averages for a hypothetical 35-year-old driver with clean record + full coverage. Your actual quote depends heavily on your age, driving history, credit, ZIP code, and insurer.

Your state (affects local premium average)

Full coverage / year

$1,607

Full coverage / month

$134

Liability only / year

$611

vs US avg

-4%

How this estimate is calculated

US base full-coverage premium$1674

× state (US)1.00x

× vehicle class (sedan-midsize)0.96x

× theft risk1.00x

× safety rating1.00x

× vehicle age1.00x

= Full coverage estimate$1607

Coverage assumed: 100/300/100 liability + comprehensive/collision, $500 deductibles. Data sources: NAIC 2024 + HLDI loss studies.

Maintenance & Warranty

Recommended Gmc SIERRA DENALI Service Intervals

Oil change

8K mi / 12 mo

Tire rotation

8K mi

Brake fluid

36 months

Transmission fluid

45K mi

Engine coolant

150K mi

Spark plugs

100K mi

Cabin air filter

23K mi

Engine air filter

45K mi

Differential (AWD/4WD)

45K mi

Uses GM Oil Life System. Full-size trucks may have shorter differential and transfer case intervals if used for towing.

"Severe service" conditions (heavy towing, extreme temps, city stop-and-go) typically halve these intervals. Always consult your vehicle's owner's manual for the authoritative schedule.

Gmc New-Vehicle Warranty Coverage

Bumper-to-bumper (basic)

3 yr / 36K mi

Powertrain

5 yr / 60K mi

Hybrid/EV battery

8 yr / 100K mi

Corrosion (rust perforation)

6 yr / 100K mi

Roadside assistance

5 yr / 60K mi

These are the terms for a new Gmc. If you're buying a used 2020 SIERRA DENALI, remaining coverage is usually pro-rated from the vehicle's original in-service date. Not all coverage transfers between owners — check with a Gmc dealer for VIN-specific remaining warranty.

Estimated Repair Costs

ENGINE(~50K mi)

$500

BRAKES(~50K mi)

$500

ELECTRICAL(~50K mi)

$500

SPEED CONTROL(~50K mi)

$500

Estimates based on average reported repair costs. Actual costs vary by location, shop, and severity.

🔍 Pre-Purchase Inspection Checklist

Based on 10 owner complaints for this specific year, here's what to check or ask about:

☐
ENGINE: I NOTICED SEVERAL SPOTS OF OIL ON MY DRIVEWAY, I THEN INSPECTED THE UNDERSIDE OF THE ENGINE (L5P) AND NOTICED OIL DRIPPING FROM SEVERAL BOLTS AND LINES. MY VEHICLE, A 2020 2500HD DENALI DIESEL, HAS ONLY 2,200 MILES ON IT FROM NORMAL HIGHWAY DRIVING.
Typically appears around 50K miles. Repair cost ~$500
☐
BRAKES: TWO ISSUES BROKEN VALVE SPRING CAUSED ENGINE TO SHUT DOWN, SECOND SERVICE BRAKE, BRAKE FAILURE LIGHT, SERVICE ESC, SERVICE TRAILER BRAKE MESSAGES CAUSING BRAKE FAILURE
Typically appears around 50K miles. Repair cost ~$500
☐
ELECTRICAL: The contact owns a 2020 GMC Sierra Denali. The contact stated while driving 65 MPH at night, the vehicle stalled and the “Shift to Neutral and Restart Vehicle” message was displayed. The contact was unable to restart the vehicle and was unable to visibly see the roadway. The contact was able to park
Typically appears around 50K miles. Repair cost ~$500
☐
SPEED CONTROL: The contact owns a 2020 GMC Sierra Denali. The contact stated while driving 75 MPH, the Adaptive Cruise Control feature became inoperable. The contact stated that when the vehicle got too close to another vehicle, the Adaptive Cruise Control feature failed to activate as designed. The vehicle was no
Typically appears around 50K miles. Repair cost ~$500
☐
General: Get a pre-purchase inspection from an independent mechanic ($100-$200)