2008 Chevrolet Cobalt engine problems

Key becomes stuck in the driving position and cannot be turned or removed while engine is running. One owner reported the car overheated to 300°F because the engine could not be shut off, resulting in catastrophic engine failure. Multiple owners report the key sticking or becoming difficult to turn.

When: Various mileages; one case involved early failure with stuck key leading to overheating

Symptoms owners cite: Key stuck in driving position and will not release; Key sticks and requires manipulation to turn; Key can be removed while engine is still running; Engine continues running when key is removed; Engine overheating due to inability to shut off

Repairs/costs cited: One owner reported engine was blown/destroyed due to overheating from inability to shut off; dealer mentioned it was a recall issue but would take about a week to repair

Recalls/TSBs owners mention: Dealer advised one owner it was a known recall problem; however multiple owners report 2008 models are not included in the recall despite experiencing identical issues

Fuel leaks from fuel supply lines, tank filler area, or evaporative emission lines. One owner reported the fuel supply line rusted completely through near the driver side rear fender well. Undiagnosed fuel leaks occur at various mileages with strong gasoline odors in and around the vehicle, creating fire hazard.

When: 55,875 miles (one case); appears across various mileages; 6,000 miles (one case)

Symptoms owners cite: Strong gasoline odor in and around vehicle; Gasoline smell while idling, progressing to overpowering smell at highway speeds; Fuel leaking from tank or fuel lines onto ground; Visible fuel leak with no visible fuel on ground (fuel meter dropping); Evaporative emission vapor line rusting and leaking

Repairs/costs cited: One owner paid $150 diagnostic fee at dealer plus repair costs; fuel supply line rusted completely through and was repaired; evaporative emission line also corroded

Recalls/TSBs owners mention: Dealers cited upcoming recalls but refused to repair under warranty; one owner reported knowing of fuel system recall for 2005-2007 models but 2008 was told it was not affected

Fires erupt in the engine compartment, some without warning and during normal driving. One fire occurred at 30 mph during normal operation; another at less than 500 miles with impact during a collision. Owner reported abnormal fuel odor preceding fire. Fires were extinguished by fire department.

When: 119,000 miles (one case); less than 500 miles (one case)

Symptoms owners cite: Fire confined to engine compartment; Abnormal fuel odor in vehicle prior to fire; Fire erupts suddenly beneath hood during driving; Fire quickly engulfed front end of vehicle

Repairs/costs cited: Vehicles were towed; fire department extinguished fires; origin of fires listed as unknown by manufacturer

Recalls/TSBs owners mention: One vehicle was not included in NHTSA fuel system recall campaign 12V459000; manufacturer was not made aware of fire in one case

Catalytic converter fails, causing scraping and grinding sounds, severe power loss, and inability to accelerate above 30 mph. One owner reported identical issue to known recall affecting 2005-2007 models but was denied coverage on 2008 model.

When: Unknown mileage; 2005-2007 models have recall but 2008 not included

Symptoms owners cite: Scraping and grinding sound from engine; Little to no engine power; Cannot accelerate above 30 mph; Loud noise from engine compartment

Repairs/costs cited: $1334.21 for new catalytic converter and two gaskets at dealership; $111.26 rental car expense due to stranded situation

Recalls/TSBs owners mention: Chevrolet acknowledged identical catalytic converter issue affects 2005-2007 Cobalts in Nevada but refused to extend recall to 2008 models despite identical symptoms

Engine dies or stalls suddenly during normal driving at various speeds without warning. Some stalls are one-time events; others are recurring. One owner reports stalling at 70 mph on highway, losing power steering, with restart occurring minutes later. Multiple owners report similar sudden stalls at 25-30 mph and 50 mph.

When: 50,000 miles (one case); 49,033 miles (one case); 60,000 miles (one case); 139,812 miles (one case); highway driving at various times

Symptoms owners cite: Engine dies suddenly while driving; No warning before stall occurs; Engine stalls and restarts after several attempts or minutes; Loss of power steering when engine dies; Repeated stalling over time; Stalling at complete stops and while driving

Repairs/costs cited: Dealers unable to duplicate failures; one crash into ditch as result of stall; owners spent money on repairs with no solution provided

Recalls/TSBs owners mention: Known recall exists (NHTSA 14V047000 for airbags/electrical) but does not cover 2008 models; after airbag recall repair, one owner's stalling problems began; dealers unable to diagnose cause

Cam chain guides break, causing slack in chain and causing it to jump teeth on intake cam, throwing cam out of synchronization and bending intake valves. Reported as very common issue on 2.2 engines but unusual at low mileage. Engine requires complete replacement.

When: Less than 79,000 miles (one case); another case at ~90,000 miles just after warranty expiration

Symptoms owners cite: Engine starts then stalls immediately; Engine will not start at all; White thick smoke from exhaust; Steering wheel vibration when starting car

Repairs/costs cited: Complete engine replacement required; one owner diagnosed by certified mechanic friend; another told by dealer that engine head and valves destroyed, new motor required

Recalls/TSBs owners mention: GM refused warranty repair despite engine being well below 100,000 mile warranty limit (only 79,000 miles), citing it only covers 5 years; manufacturer denied design flaw exists

Check engine light illuminates with 'Reduced Engine Power' warning, causing sudden loss of acceleration and speed reduction. Occurs during rain or wet conditions at highway speeds. Car shakes and traction control light also illuminates. Requires waiting hours for light to reset.

When: Various; recurring issue, including highway driving at 50 mph

Symptoms owners cite: Reduced Engine Power light illuminates suddenly; Car cannot accelerate or slows dramatically; Cannot pick up speed even with gas pedal pressed; Check engine light comes on; Traction control light comes on; Car shakes while condition is active; Occurs during rain/wet driving conditions

Codes mentioned: Check Engine

Repairs/costs cited: Requires waiting hours for light to turn off; multiple occurrences required waiting 2 hours on highway

Coolant level gauge stops reading, check engine light comes on, and A/C stops working. Problem self-corrects before diagnostic can be completed at shop, making diagnosis difficult. May be thermostat or sensor issue but cannot be diagnosed without active fault codes.

When: 40,000 miles (one case); ongoing for couple months in another

Symptoms owners cite: Coolant gauge does not read/display; Check engine light comes on intermittently; Air conditioner stops working; Thermostat becomes inoperable; Problem disappears when taken to shop; No diagnostic codes present when checked

Repairs/costs cited: Shop suspects thermostat or sensor but cannot diagnose without codes; no repairs completed

Engine runs rough, check engine light and service traction light illuminate, and transmission shifts hard. Owner reports feeling like engine will stall. Diagnosed as cylinder misfire but no resolution provided.

When: Unknown mileage

Symptoms owners cite: Engine runs very rough; Service traction light comes on; Check engine light comes on; Hard transmission shifts; Feeling like engine will stall; Shaking

Codes mentioned: Cylinder Misfire

Check engine light illuminates constantly with unknown cause. Suspected oxygen sensor defect but not definitively diagnosed. Cannot be repaired without clear diagnostic code.

When: Unknown mileage

Symptoms owners cite: Check engine light illuminated constantly; Unknown failure cause

Codes mentioned: Check Engine

Engine momentarily loses power while driving uphill on county highway in humid, 80-degree conditions. Engine restarts itself and vehicle continues moving.

When: Unknown mileage

Symptoms owners cite: Engine loses power momentarily while driving uphill; Engine self-restarts

Engine fails catastrophically with white smoke and popping sound at very low mileage with no prior warning. Dealership diagnosed as engine explosion requiring complete replacement.

When: 6,000 miles

Symptoms owners cite: Popping sound from engine; White smoke coming from engine; Engine exploded

Repairs/costs cited: Engine replacement required at dealership

RPMs fluctuate up and down during steady driving; fuel odor detected during idle progressing to very strong smell. Engine does not start easily if sitting more than a few hours. Fuel system does not allow enough fuel to reach engine.

When: Late 2011 onwards; issue has persisted since February 2012

Symptoms owners cite: RPMs go up and down while driving at steady pace; Gasoline smell while idling; Strong fuel odor at highway speeds (70+ mph); Difficult cold start after sitting; Engine runs rough during idle; Requires multiple start attempts after vehicle sits

Repairs/costs cited: Dealership quoted $150 diagnostic fee and double the price for repair; owner refused to pay

Recalls/TSBs owners mention: Dealer acknowledged issue on earlier models but claimed 2008 models do not have the issue despite identical symptoms; manufacturer has not fixed problem