This informational bulletin provides information on close coupled converters and there affect on newly installed engines or engines during there break in period.
full bulletin at NHTSA ↗2005 GMC Sierra engine problems
severe 44 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
44
Recalls
0
Avg fix
$3,100
3fires
When does it fail?
Of the 44 engine complaints filed for the 2005 GMC Sierra, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 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
Owners have filed 44 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.
No new NHTSA engine complaint has been filed on this vehicle in over 10 years — the issue may be aging out of the active population.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This informational bulletin provides information to technicians regarding intake manifold inspection/replacement after severe internal engine damage.
full bulletin at NHTSA ↗This technical bulletin provides repair information for repairing the IP to body harness connector to correct a customer concern for intermittent Malfunction Indicator Lamp (MIL) illuminated with Reduced Engine Power displayed and DTC P2138 set.
full bulletin at NHTSA ↗GENERAL MOTORS: INTERMITTENT MIL/SES/ DTC P2138 WITH REDUCED ENGINE POWER (REPAIR INSTRUMENT PANEL (IP) TO BODY HARNESS CONNECTOR). 2005-08 GM PASSENGERS CARS/LIGHT DUTY TRUCKS (INCL. SATURNS). UPDATED 11/5/10. UPDATED 4/4/11. UPDATED 2/3/16.
full bulletin at NHTSA ↗GMC/CHEVROLET: ENGINES, WITH EGR SYSTEM, HAS LEAKAGE FROM EGR COOLER ENGINE COOLANT INTO THE COMBUSTION CHAMBER. MODEL 2002-15 SILVERADO, SIERRA, 2004-09 KODIAK C4500-C5500, TOPKICK C4500-C5500, 2006-15 EXPRESS, SAVANA.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2005 GMC Sierra, particularly the 2500HD models, has generated 44 complaints centered on critical engine issues. The most frequent complaint—exhaust manifold bolt breakage—appears across multiple narratives starting around 32,000 miles and recurring even after repair. Owners report bolts snapping on both sides of the engine, allowing raw exhaust into the cabin and engine bay. A mechanic cited 12 shops having replaced these on roughly 12 vehicles each; one owner noted over 12,000 vehicles affected industry-wide.
Duramax diesel owners report chronic overheating during towing—the truck's primary function. Temperatures exceed 230°F while pulling loads the truck is rated to handle, forcing drivers off the road and creating highway hazards.
Gasoline models with the 5.3L engine suffer internal coolant leaks from defective CASTECH cylinder head castings (GM TSB 06-06-01-019B), contaminating oil and threatening engine failure. Owners cite $3,100–$5,000 repair costs with dealers dismissing the issue.
Sudden engine power loss and stalling at highway speeds—sometimes accompanied by instrument cluster malfunctions—has stranded multiple owners. One owner's research linked the problem to throttle position sensor failure, though GM's extended warranty excludes 2005 models.
Additional reported failures include blower motor resistor fires, engine fires, cracked cylinder heads, and rough idle that dealers claim is normal.
Same GMC Sierra engine reports on nearby years: 2007 · 2008
Failure modes owners describe
Exhaust Manifold Bolt Breakage
Bolts fastening the exhaust manifold to the cylinder head break or snap off, allowing exhaust leaks into the engine bay and potentially the cabin. Occurs on both gasoline (5.3L and 6.0L) and diesel engines. Owners report this as a widespread problem affecting thousands of vehicles, with dissimilar metals (steel bolts, cast iron manifolds, aluminum heads), heat cycling, and moisture causing premature corrosion and failure.
When: 35,000 to 94,000 miles; some as early as 32,000 miles on previous vehicles
Symptoms owners cite: Check engine light illumination; Exhaust leak/hissing sound; Ticking or knocking noise; Exhaust fumes in cabin or engine bay; Exhaust smell during operation
Codes mentioned: P0420 or similar emissions-related codes (implied from exhaust leaks)
Repairs/costs cited: Exhaust manifold removal, bolt extraction, replacement of bolts, new gaskets and seals, oil dipstick tube replacement if damaged. Owners cite repair costs of $2,500 or more. Some owners report the problem recurring even after dealer repair.
Coolant Loss/Head Casting Defects (CASTECH Heads)
5.3L engines equipped with CASTECH 706 cylinder heads suffer from porosity defects in the casting, causing coolant to leak internally into the oil and oil galleries without visible external leaks. Coolant contamination can lead to engine failure if not addressed. GM issued TSB 06-06-01-019B acknowledging this defect affects roughly 50% of heads from one manufacturing batch in model years 2001–2006. Some owners report cracked cylinder heads as a separate but related issue.
When: Throughout vehicle life; coolant loss detectable at 60,000+ miles
Symptoms owners cite: Coolant loss over time with no visible external leaks; Oil appears milky or diluted with glycol; Coolant may discharge from overflow line on cold start; Engine overheating
Repairs/costs cited: Cylinder head replacement required to prevent engine failure. Repair costs cited at $3,100 to $4,000+ for parts and labor. Dealers sometimes advise only monitoring the issue.
Recalls/TSBs owners mention: GM issued TSB 06-06-01-019B; some dealers acknowledge the defect but do not initiate recalls or warranty coverage despite identifying it as known.
Duramax Diesel Overheating Under Load/Towing
6.6L Duramax diesel engines, particularly 2004.5 and 2005 models, experience chronic overheating when towing or hauling, the primary intended use of these trucks. Engine temperatures exceed safe operating limits (230°F+) and transmission temperatures spike (210°F+). Owners report this is a widespread issue affecting hundreds or thousands of vehicles. Problem manifests during hill climbing, mountain grades, and trailer towing at rated capacity. Cooling fan operates constantly at high noise levels. Dealers cannot replicate or fix the issue; GM acknowledges awareness but offers no documented solution.
When: Occurs consistently during towing/hauling; typically noted within first 2 months of ownership or during initial towing attempts
Symptoms owners cite: Engine temperature gauge reading 230°F or higher during towing; Transmission temperature exceeding 210°F; Loss of power while towing uphill; Engine overheating shutdown; Constant fan noise; Check engine light (on some vehicles)
Repairs/costs cited: No documented repair solution provided by owners. Dealers unable to simulate or fix condition. Some mention buyback involvement by GM, but no parts or procedures are cited.
Recalls/TSBs owners mention: GM acknowledges problem exists but states no solution has been identified; some dealers deny problem; potential buyback arrangements mentioned but not detailed.
Throttle Position/Accelerator Control System Failure
Engine loses power abruptly while driving, with check engine light and 'Reduced Power Mode' or 'Engine Power Reduced' message displayed on instrument cluster. Vehicle may stall or become difficult to restart. Owner research and internet forums indicate throttle position sensor (TPS) failure as likely cause. GM has issued extended coverage for 2008+ models and vehicles up to 10 years/120,000 miles, but 2005 models fall outside this coverage. Similar incidents occur repeatedly even after throttle body replacement.
When: Various mileages reported; one instance at 270,000 miles
Symptoms owners cite: Sudden loss of engine power while driving; 'Engine Power Reduced' or 'Reduced Power Mode' message on display; Check engine light illumination; Engine hard to crank or stalls; Vapor lock appearance (difficulty restarting); Engine dies while stopped or coasting
Codes mentioned: Check engine light (specific codes not detailed in narratives)
Repairs/costs cited: Throttle body replacement, throttle body wire harness repair, throttle accelerator control module replacement, and accelerator pedal assembly repair cited. Despite multiple repairs, failure has recurred.
Recalls/TSBs owners mention: GM has issued extended coverage for 2008+ models (10 years/120,000 miles); 2005 models not covered by this program.
Blower Motor Speed Control Resistor/Relay Failure
HVAC blower speed controller relay connector experiences contact resistance failure, overheating when fan is set to high speed. Undersized connector on the relay controller combined with galvanic corrosion between dissimilar metals (tinted copper wire harness, bare metal relay connector) causes excessive resistance and heat generation. Connector and wire harness burn out, producing heavy smoke. Speed control resistor unit, mounted in the air stream, collects condensation from air conditioning use, leading to corrosion of the resistor board.
When: Occurs when activating high blower speed
Symptoms owners cite: Heavy smoke from HVAC blower system when turned to high speed; Burned connector and wire harness; Blower motor inoperative
Repairs/costs cited: One owner performed workaround: bypassed connector by joining blower motor return wire directly to controller input wire with jumper wire. No formal repair procedure cited. TSB 060139002 mentioned for Engine and Engine Cooling (applied to different model year or context).
Engine Fire/Electrical Fire
Vehicle caught fire in the engine compartment approximately three hours after parking. One instance involved smoke coming from air vents while driving on interstate, with vehicle erupting into flames. Fire originated in engine compartment. Potential electrical or fuel system origin, though specific cause not detailed in narratives.
When: 54,000 miles (one instance); timing unknown for another
Symptoms owners cite: Smoke from air vents/engine compartment; Vehicle erupts into flames; Fire originating in engine compartment
Repairs/costs cited: Vehicle destroyed in fire. One owner cited loss of personal items and missed work due to vehicle loss.
Engine Stalling/Loss of Power While Driving
Engine dies unexpectedly while driving at speed or when coasting to a stop, with no warning signs beforehand. Vehicle becomes immobile and difficult to restart, stranding the driver. Multiple service visits have not resolved the issue. Transmission jumping or hunting also reported in conjunction with stalling.
When: Various mileages; one instance at 5 mph coasting
Symptoms owners cite: Engine stalls without warning while driving; Difficulty restarting engine; Vehicle immobilized for extended periods (10+ minutes reported); Transmission jumping (in one case)
Repairs/costs cited: Multiple dealer service attempts have failed to resolve. No specific repairs successful.
Recalls/TSBs owners mention: GM promised to send representative to investigate; promise not fulfilled per owner report.
Instrument Cluster/Speedometer Malfunction
Speedometer displays erratic readings, becoming stuck at various speeds (47–120 mph) while vehicle is actually at different speeds or parked. Creates safety hazard as driver cannot accurately determine vehicle speed. Check engine light also reported in same narrative as engine stalling.
When: 72,300 miles
Symptoms owners cite: Speedometer stuck at fixed reading; Speedometer displaying 100–120 mph while parked or at actual lower speeds; Inoperative speedometer at startup
Repairs/costs cited: Owner took vehicle to dealer for diagnosis; no repair outcome documented in narrative.
Rough Idle and Engine Stumbling (5.3L)
Engine exhibits rough idle after warm-up with noticeable stumbling and vibration when vehicle is stopped at traffic lights. Cab shakes from the severity of the stumble. Dealership computer diagnostic found no defects and advised this is normal behavior for the 5.3L engine in this model year.
When: After engine warm-up
Symptoms owners cite: Rough idle after warm-up; Engine stumbling at stop lights; Cab shaking from idle quality
Repairs/costs cited: No repair attempted; dealer deemed behavior normal.
Recalls/TSBs owners mention: Dealer stated this is normal for 5.3L engine in this model year.
Cracked Cylinder Head/Cracked Flywheel
Engine develops cracked cylinder head or cracked flywheel. One owner reported knocking noise on start, diagnosed as cracked cylinder by dealership mechanic who stated this is a 'common' problem with the truck. Another owner had flywheel crack, requiring replacement, though problem persisted after repair.
When: 20,000 miles (flywheel); low mileage and regularly serviced (cylinder head)
Symptoms owners cite: Knocking noise on engine start; Metallic knocking sound from engine
Repairs/costs cited: Flywheel replacement attempted but problem persisted. Cylinder head crack repair costs in the thousands; owner stated inability to afford repair.
Recalls/TSBs owners mention: Dealer acknowledged cracked cylinders are 'common' but declined to address under warranty.
Oil Leak/Rear Main Seal Failure
Engine oil leaks from rear main seal area. Oil drips onto hot exhaust pipe and begins to burn, creating potential fire hazard.
When: Unspecified mileage
Symptoms owners cite: Oil dripping from engine; Oil burning on exhaust pipe (smoke/smell); Fire hazard from hot oil on exhaust
Repairs/costs cited: No repair details provided in narrative.
Charge Air Cooler Oil Leak (Diesel)
Charge air cooler leaks residual oil from lower right corner, creating visible puddle or staining.
When: 35,000 miles
Symptoms owners cite: Oil leaking from lower right corner of charge air cooler
Repairs/costs cited: Oil leak noted; repair action not detailed in narrative.
EVAP System/Fuel Cap Issues
Check engine light illuminates due to evaporation (EVAP) system fault. Evaporation vent and filter require replacement.
When: 110,000 miles
Symptoms owners cite: Check engine light illumination
Codes mentioned: EVAP system code (specific code not provided)
Repairs/costs cited: Evaporation vent and filter replacement performed.
Synthesized from 44 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 2 most recent
Engine exhaust manifold bolts break off on 2 different gm 1 ton trucks. Bad/ failed vehicle emissions and a huge repair bill for both trucks. 85,000 miles on both vehicles.
GMC pickup developed coolant loss. Took in and found that head had cracked. Service bulletin revealed 50% of heads for that year came from one manufacturer and had been prone to cracking. Discovered mine indeed had the suspect head and did have the crack as described. Why didn't GMC issue a recall on these and save me $4,000? *tr
Had engine trouble with your 2005 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 2005 GMC Sierra?
It's a meaningful issue. 44 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $3,100.
At what mileage does the engine typically fail?
Across the 38 complaints that reported odometer mileage, most engine failures cluster between 20,615 and 94,500 miles, with the median around 72,300. A quarter of owners report trouble before 20,615; a quarter make it past 94,500. 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/2005/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.