General Service Bulletin 22-7078 - Various Vehicles - Engine Failure Analysis

[Haz]

GENERAL SERVICE BULLETIN Various Vehicles - Engine Failure Analysis	22-7078 23 May 2022
This bulletin supersedes 20-7062.   Summary This article supersedes GSB 20-7062 to update the vehicle model years affected.   This bulletin is a guide to engine failure analysis and preventing repeat engine failure.   Service Information   Determining Root Cause Understanding normal engine wear vs. actual engine damage can increase the accuracy of determining the root cause. If the true root cause of the engine failure is not identified with visual confirmation, an over repair or incomplete repair leading to repeat engine failure may result. Root cause determination and the extent of engine damage is necessary during engine assessment. Inspection areas include:   • Oil filter • Oil pan • Cylinder head and deck surfaces • Camshaft bores, journals and lobes • Crankshaft journals • Cylinder walls and piston skirts • Rod and main bearings   Engine Analysis   Metal in the Oil Pan, Filter and/or Screens – Acceptable Conditions Some metal in the oil pan and filter is expected and considered normal (Figures 1-2).   Figure 1     Figure 2     Some metal shavings in the oil filter are not a concern (Figure 3).   Figure 3     Small specs of metal in the filter media is normal (Figure 4).   Figure 4   Assembly paint is not a concern. Do not confuse with bearing material.   Metal in the Oil Pan, Filter and/or Screens – Unacceptable Conditions Large chunks of metal in the pan and/or filter merit further root cause investigation (Figures 5-6).   Figure 5     Figure 6     Excessive amounts of metal in the oil filter and/or screens require further root cause investigation (Figures 7-8).   Figure 7     Figure 8     Camshaft Bore, Journal and Lobe Inspection   Cam Bore – Normal Wear: Polishing, discoloration, slight porosity or minor scoring (Figures 9-10).   Figure 9     Figure 10     Cam Bore – Damage: Material loss, deep scoring and severe porosity (Figures 11-12).   Figure 11     Figure 12     Camshaft Journals and Lobes - Normal Wear: Polishing, discoloration, minor uniform scoring felt with a fingernail (Figures 13-15).   Figure 13     Figure 14     Figure 15     Camshaft Journals and Lobes – Damage: Material loss/transfer, deep scoring or bluing of the metal are all signs of damage (Figures 16-18).   Figure 16     Figure 17     Figure 18     Crankshaft and Bearing Inspection   Bearings – Normal Wear: Polishing, discoloration, light scoring, light contact with red coating (Figures 19-22).   Figure 19     Figure 20     Figure 21     Figure 22   NOTE: Bearings are designed to manage some debris; therefore, some light scoring found on the bearing surface is not necessarily an indication of engine failure or root cause determination.   Bearings – Damage: Metal transfer, erosion, material loss, coolant contamination, deep scoring, cracking, spun bearing (Figures 23-27).   Figure 23     Figure 24     Figure 25     Figure 26     Figure 27     Crankshaft – Normal Wear: Discoloration, polishing, light scratches (Figures 28-29).   Figure 28     Figure 29     Crankshaft – Damage: Material loss, deep scoring, material transfer (Figures 30-32).   Figure 30     Figure 31     Figure 32     Head and Block Surface Inspection   Head and Block Surface – Normal Wear: Porosity outside sealing surfaces, gasket surface discoloration, light scratches (Figures 33-34).   Figure 33     Figure 34     Head and Block Surface – Damage: Porosity on sealing surfaces, deep gouges, material transfer, warpage (Figures 35-37).   Figure 35     Figure 36     Figure 37     Cylinder Wall and Piston Skirt Inspection   Cylinder Wall – Normal Wear: Slight polishing and/or discoloration, vertical streaking, slight scoring, cross hatch present, light staining (Figures 38-40).   Figure 38     Figure 39     Figure 40     Cylinder Wall – Damage: Deep gouging, impact marks, loss of crosshatch, cracks (Figures 41-43).   Figure 41     Figure 42     Figure 43     Piston Skirt – Normal Wear: Light wear of the coating (Figures 44-45).   Figure 44     Figure 45     Piston Skirt – Damage: Deep scoring, severe coating wear (Figure 46-47).   Figure 46     Figure 47   Preventing Repeat Engine Failures Identifying certain failure modes such as detonation, running lean, oil consumption and/or hydro-locking will help determine if further inspection of components is required to prevent repeat failures.   Piston and Cylinder Wall Damage   Root Cause: Lean conditions or modifications (Figures 48-49)   Figure 48     Figure 49   • Modifications (timing, CNG, incorrect spark plugs) - Overboost (supercharger/turbocharger) - PCM performance chip/programmer   • Lean conditions - Mass air flow (MAF) sensor failure - Damaged air intake   Effect: High cylinder pressure or spark knock • Excessive combustion temperatures • Excessive cylinder pressure • Pre-ignition • Excessive levels of detonation (low octane/poor fuel quality) Damage: Piston and cylinder wall • Spark plug electrode damage • Hole in piston (pre-ignition) • Piston ring land damage (detonation) • Pitted piston face • Cylinder wall scoring Spark plug damage (porcelain fracture or melted electrode) is an indication of excess detonation (Figure 50)   Figure 50     Heat generated from friction can cause cylinder walls to crack. (upper ring land damage) (Figure 51)   Figure 51     Excess detonation causes excess cylinder pressure spikes leading to piston ring land fractures (second ring land is damaged). (Figure 52)   Figure 52     Cylinder Wall Damage (Figure 53)   Figure 53   Root Cause: Fuel/air mixture concerns • Excess oil consumption • Lean/rich conditions • Cylinder misfire Effect: Catalyst damage • Catalyst material begins to deteriorate (turns to dust/sand) • Catalyst material is pulled into the engine Damage: Cylinder wall • Cross hatch is polished away • Vertical scoring • Bearing damage may be present if catalyst material made it to the engine oil. Check for catalyst debris by shaking out the converter onto a clean surface (Figure 54)   Figure 54     Catalyst material can collect on the sides of the piston damaging cylinder wall surfaces (Figure 55)   Figure 55     Valve Damage (Figures 56-57)   Figure 56     Figure 57     Root Cause: Lean condition • Modification or damage to the air induction system • MAF sensor damage/failure • Lack of fuel to the cylinder Effect: Excessive combustion chamber temperatures • Misfire, lacks power • Catalyst damage • Running lean = hot cylinder Damage: Valve and valve seat • Valve tuliping • Valve seat recession (Figure 58)   Figure 58     If cylinder leakage is present past the valves: • Check for valves held open by other valvetrain components • Check for the valve stem sticking in the guide • Inspect for debris between the valve and seat that could hold the valve open Excessive lean conditions can cause valves to overheat and soften. Over time, the valve can stretch and deform against the seat causing the valve to “tulip” creating leakage and a misfire. Comparing total valve height of the suspect valve to a known good valve can help identify issues. A height difference in the suspect valve is an indication of valve tuliping. Valve tuliping is the effect, not the root cause of the concern.   Foreign Object Debris (Figure 59)   Figure 59     Root Cause: Combustion chamber damage • Broken piston/rings • Broken valves • Dropped valve seats Effect: Debris transfer • Original intake manifold transferred to the new engine • Intake manifolds cannot be cleaned in these instances and require replacement Damage: Repeat engine failure • Engine vacuum dislodges debris left in the manifold • Debris will enter the combustion chamber and cause piston/cylinder damage (Figure 60)   Figure 60   • Foreign object debris can cause metal transfer from the piston to the cylinder head • This metal debris can also make it to the intake manifold • The intake manifold must be replaced in these instances to prevent repeat damage Bearing Damage (Figure 61)   Figure 61   Root Cause: PCV system concerns • PCV system damaged • Open breather tube in place of PCV valve • Lack of oil maintenance Effect: Oil consumption • Oil is pulled through the engine and burned off Damage: Bearing damage • Bearing and journal damage from lack of lubrication • An open breather tube fitting mistaken for a PCV valve could be transferred to the new engine leading to repeat bearing failure (Figure 62). During engine replacement, verify the PCV valve is operational and correct for the application. Figure 62   NOTE: Remanufactured Modular 2V V8 and V10 engines do not come with a PCV valve installed. If there appears to be a valve/tube in place on a new Remanufactured 2V V8 or V10 engine, replace it.   Bent Connecting Rod (Figure 63)   Figure 63   Root Cause: Hydrolocking from liquid ingestion • Leaking or stuck open fuel injector • Water ingestion through the air inlet (wet, warped or damaged air filter) Effect: Hydrolocking • Liquid cannot be compressed and will prevent the piston from traveling to top dead center (TDC) Damage: Connecting rod • Connecting rod will bend or break • May occur on more than one cylinder (Figures 64-65)   Figures 64     Figure 65   • Since fluids cannot be compressed, the connecting rod typically suffers from a hydrolock event.   © 2022 Ford Motor Company All rights reserved. NOTE: This information is not intended to replace or supersede any warranty, parts and service policy, workshop manual (WSM) procedures or technical training or wiring diagram information.