6.2L Engine Problems

Three engines share a name. Not a build sheet.

"6.2" has been stamped on the valve covers of at least three unrelated V8s since 1982. This sheet separates them and lists what actually breaks on each — symptoms, cause, and what a shop will tell you.

Find your engine by RPO or build year below. Each entry covers the issue owners report most, in the order a mechanic would rule things out — noise first, then oil, then everything downstream of both.

Jump to your engine

• 01 — GM EcoTec3, Gas
• 02 — Ford Modular, Gas
• 03 — Detroit Diesel, Indirect Injection
• At a glance
• When to stop driving

01 — GM EcoTec3, Gas

GM 6.2L V8 — L86 / L87 / LT1 / LT2 / LSA
2014–present
Silverado · Sierra · Tahoe · Yukon · Escalade · Corvette · Camaro
Direct injection, cylinder deactivation

Active Fuel Management (AFM/DFM) lifter failure

The headline issue on this family. To run in 4-cylinder mode under light load, these engines rely on lifters built to collapse on command — and those lifters are the known weak point.

Symptoms: a metallic tick-tick-tick from the top end, worse cold or at idle; check-engine light; misfire codes P0300, P0301, P0304, P0306, P0307; rough idle.
Left unaddressed: a collapsed lifter can shed metal into the oil and take the camshaft with it — a $200 part turning into a $7,000 engine.
Fix: replace the failed lifters, and consider an AFM/DFM delete at the same time — lifters-only repairs have a real recurrence rate within 20,000–60,000 miles.

Caution: new ticking noise on a 5.3L or 6.2L GM V8 — get it looked at before the next long drive. This is the one failure mode on this sheet that gets dramatically more expensive if you keep driving on it.

Excessive oil consumption

Symptoms: needing to top off between changes, low-oil alerts.
Cause: worn piston rings, a tired PCV system, or early-stage lifter wear.

Exhaust manifold bolt breakage

Symptoms: a cold-start tick that fades as the engine warms — commonly mistaken for a lifter tick.
Cause: repeated heat cycling loosens or snaps the manifold bolts.
Fix: replace the full bolt set, not just the broken ones.

Flex-fuel sensor faults (E85 models)

Symptoms: fuel-trim codes P0171, P0172, P0174, P0175; sluggish drivability.
Cause: a bad sensor misreports ethanol content, so the ECM miscalculates fuel delivery.

02 — Ford Modular, Gas

Ford 6.2L V8 "Boss"
2010–2022
F-150 SVT Raptor · F-250/F-350 Super Duty
16 spark plugs, 2 per cylinder

Broken valve springs

Symptoms: rough running, misfires, knocking, sudden power loss; a dropped valve stem can cause serious internal damage.
Cause: the 16 valve springs fatigue under the engine's output, typically showing up past 100,000 miles.

Spark plug & ignition issues

Symptoms: rough idle, hesitation, misfires.
Cause: double the usual plug count means double the failure points. The rear bank sits against the firewall, and plugs are known to break or seize in the head on removal.

Oil leaks & consumption

Symptoms: visible leaks, a burning-oil smell, frequent top-offs.
Common sources: valve cover gaskets (including the right-side cover baffle), oil pan gasket, rear main seal, PCV valve.

Service bulletin: Ford TSB 15-0161 (Oct. 2015) covers excessive oil consumption on 2015–2016 Super Duty trucks built between March 1, 2014 and September 8, 2015.

03 — Detroit Diesel, Indirect Injection

GM 6.2L V8 — Diesel
1982–1993
C/K trucks · Suburban · Blazer
Not related to the later 6.6L Duramax

Crankshaft failure

Symptoms: a sudden loud knock followed by engine failure.
Cause: a worn or defective harmonic balancer stops absorbing vibration properly, and the stress eventually cracks the crank. Aftermarket turbocharging — which the stock bottom end wasn't built for — makes it markedly worse.

Glow plug failure

Symptoms: hard cold starts, especially in winter.
Complication: the plugs are prone to swelling in the head, making them difficult to remove intact.

Overheating & head gasket failure

Symptoms: climbing coolant temperature, coolant loss, white exhaust smoke.
Cause: a factory cooling system that's undersized for the engine's heat output under load, leading to blown gaskets and cracked heads or blocks over time.

Context: reputation aside, this engine is generally dependable kept stock and maintained. Its worst failures show up when it's pushed past factory spec — heavy towing, turbocharging, or a neglected cooling system.

At a glance

When to stop driving and get it looked at

Any one of these is worth a shop visit before the next trip:

• A new tick, knock, or tap from the engine, especially on cold start
• A check-engine light paired with a misfire code
• Oil you're topping off between scheduled changes
• Rising coolant temperature or a visible coolant/oil leak