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Engine System - General Information: Other Lincoln MKS I

Mechanical 37 illustrations ~4137 words

MATERIAL CHART

ItemSpecificationFill Capacity
Dye-Lite® Gasoline Engine Oil Leak Detection Dye 164-R3700 (Rotunda)29.6 ml (1 oz)
Motorcraft® SAE 5W-20 Premium Synthetic Blend Motor Oil XO-5W20-QSP (US); Motorcraft® SAE 5W-20 Super Premium Motor Oil CXO-5W20-LSP12 (Canada); or equivalentWSS-M2C930-A
Threadlock 262 TA-26WSK-M2G351-A6

MATERIAL CHART

Note. When repairing engines, all parts must be contamination free. If contamination/foreign material is present when repairing an engine, premature engine failure may occur.

Note. Specifications show the expected minimum or maximum condition. Refer to the appropriate Engine article for the procedure.

Note. If a component fails to meet the specifications, it is necessary to refinish it or install a new component. Wear limits are provided as an aid to determine if the component can be refinished. A new component must be installed when any component fails to meet specifications and cannot be refinished.

Note. This service information contains information, steps and procedures that may not be specific to this engine.

This service information covers general procedures and diagnosis and testing of the engine system, except for exhaust emission control devices, which are covered in the INTRODUCTION - GASOLINE MODELS .

The engine incorporates the following features: Refer to the appropriate Engine article for the procedure.

  1. Crankcase ventilation or breather system
  2. Exhaust emission control system
  3. Evaporative Emission (EVAP) control system

Some engines incorporate a fail-safe cooling system. Refer to the appropriate Engine article for the procedure.

The engine, fuel system, ignition system, emissions system and exhaust system all affect exhaust emission levels and must be maintained according to the maintenance schedule. Refer to the scheduled Maintenance Guide.

Correct engine identification is required to order parts. Refer to the appropriate Engine article for the procedure.

For complete vehicle and engine identification codes, refer to IDENTIFICATION CODES .

Material

ItemSpecification
Dye-Lite® Gasoline Engine Oil Leak Detection Dye 164-R3700 (Rotunda)
Motorcraft® SAE 5W-20 Premium Synthetic Blend Motor Oil XO-5W20-QSP (US); Motorcraft® SAE 5W-20 Super Premium Motor Oil CXO-5W20-LSP12 (Canada); or equivalentWSS-M2C930-A

MATERIAL CHART

There are 2 diagnostic paths that can be followed depending on the type of engine concern. Carry out INSPECTION AND VERIFICATION - Engine Performance or INSPECTION AND VERIFICATION - NVH .

Component Tests

The following component tests are used to diagnose engine concerns.

Engine Oil Leaks

Note. When diagnosing engine oil leaks, the source of the leak must be positively identified prior to repair. If the vehicle is driven extensively between adding the fluorescent additive and performing the leak test, fan air or wind can spread the leaking oil and make identifying the location of the leak difficult.

Prior to carrying out this procedure, clean the cylinder block, cylinder heads, valve covers, oil pan and flywheel with a suitable solvent to remove all traces of oil.

Engine Oil Leaks - Fluorescent Oil Additive Method

Use the 12 Volt Master UV Diagnostic Inspection Kit to carry out the following procedure for oil leak diagnosis.

  1. Add 29.6 ml (1 oz) of gasoline engine oil dye to a minimum of 0.47L (1/2 qt) and a maximum of 0.95L (1 qt) engine oil and fill through the engine oil fill. Thoroughly premix the gasoline engine oil dye or it will not have enough time to reach the crankcase, oil galleries and seal surfaces during this particular 15 minute test. The additive must be mixed well with oil and added through the oil fill. Check the level on the oil level indicator to determine what amount of oil to premix. If it is in the middle of the crosshatch area or below the full mark, use 0.95L (1 qt). If it is at the full mark, use 0.47L (1/2 qt).
  2. Run the engine for 15 minutes. Stop the engine and inspect all seal and gasket areas for leaks using the UV Leak Detector Kit. A clear bright yellow or orange area will identify the leak. For extremely small leaks, several hours may be required for the leak to appear.
  3. At the end of test, make sure the oil level is within the upper and lower oil indicator marks. Remove oil as necessary if it registers above the full mark.

Leakage Points - Underhood

Examine the following areas for oil leakage

  1. Valve cover gaskets
  2. Cylinder head gaskets
  3. Oil cooler, if equipped
  4. Oil filter adapter
  5. Engine front cover
  6. Oil filter adapter and filter body
  7. Oil level indicator tube connection
  8. Engine Oil Pressure (EOP) switch

Leakage Points - Under Engine, With Vehicle on Hoist

Examine the following areas for oil leakage

  1. Oil pan gaskets
  2. Oil pan sealer
  3. Engine front cover gasket
  4. Crankshaft front seal
  5. Crankshaft rear oil seal
  6. Oil filter adapter and filter body
  7. Oil cooler, if equipped

Leakage Points - With Transmission and Flywheel Removed

Examine the following areas for oil leakage

  1. Crankshaft rear oil seal
  2. Rear main bearing cap parting line
  3. Flexplate mounting bolt holes (with flexplate installed)
  4. Pipe plugs at the end of oil passages

Oil leaks at crimped seams in sheet metal parts and cracks in cast or stamped parts can be detected when using the dye method.

Cylinder Leakage Detection

When a cylinder produces a low reading, use of a cylinder leakage tester will be helpful in pinpointing the exact cause.

The leakage tester is inserted in the spark plug hole, the piston is brought up to Top Dead Center (TDC) on the compression stroke, and compressed air is admitted.

Once the combustion chamber is pressurized, the leakage tester gauge will read the percentage of leakage. Leakage exceeding 20% is excessive.

While the air pressure is retained in the cylinder, listen for the hiss of escaping air. A leak at the intake valve will be heard in the Throttle Body (TB). A leak at the exhaust valve can be heard at the tailpipe. Leakage past the piston rings will be audible at the PCV connection. If air is passing through a blown head gasket to an adjacent cylinder, the noise will be evident at the spark plug hole of the cylinder into which the air is leaking. Cracks in the cylinder block or gasket leakage into the cooling system may be detected by a stream of bubbles in the radiator.

Excessive Engine Oil Consumption

Nearly all engines consume oil, which is essential for normal lubrication of the cylinder bore walls and pistons and rings. Determining the level of oil consumption may require testing by recording how much oil is being added over a given set of miles.

Customer driving habits greatly influence oil consumption. Mileage accumulated during towing or heavy loading generates extra heat. Frequent short trips, stop-and-go type traffic or extensive idling, prevent the engine from reaching normal operating temperature. This prevents component clearances from reaching specified operating ranges.

The following diagnostic procedure may be utilized to determine internal oil consumption. Make sure that the concern is related to internal oil consumption, and not external leakage, which also consumes oil. Verify there are no leaks before carrying out the test. Once verified, the rate of internal oil consumption can be tested.

A new engine may require extra oil in the early stages of operation. Internal piston-to-bore clearances and sealing characteristics improve as the engine breaks in. Engines are designed for close tolerances and do not require break-in oils or additives. Use the oil specified in the Owner's Literature. Ambient temperatures may determine the oil viscosity specification. Verify that the correct oil is being used for the vehicle in the geographic region in which it is driven.

Basic Pre-checks

  1. For persistent complaints of oil consumption, interview the customer to determine the oil consumption characteristics. If possible, determine the brand and grade of oil currently in the oil pan. Look at the oil filter or oil-change station tags to determine if Ford-recommended maintenance schedules have been followed. Make sure that the oil has been changed at the specified mileage intervals. If vehicle mileage is past the first recommended drain interval, the OEM production filter should have been changed.
  2. Ask how the most current mileage was accumulated. That is, determine whether the vehicle was driven under the following conditions: Extended idling or curbside engine operation Stop-and-go traffic or taxi operation Towing a trailer or vehicle loaded heavily Frequent short trips (engine not up to normal operating temperature) Excessive throttling or high engine-rpm driving
  3. Verify that there are no external leaks. If necessary, review the diagnostic procedure under Engine Oil Leaks in the «DIAGNOSIS AND TESTING»(ref-375993-S06376438282010103100000) .
  4. Inspect the crankcase ventilation system for: disconnected hoses at the valve cover or TB . loose or missing valve cover fill cap. missing or incorrectly seated engine oil level indicator. incorrect or dirty PCV valve. a PCV valve grommet unseated in the valve cover (if so equipped).
  5. Inspect for signs of sludge. Sludge affects PCV performance and can plug or restrict cylinder head drainback wells. It can also increase oil pressure by restricting passages and reducing the drainback capability of piston oil control rings. Sludge can result from either excessive water ingestion in the crankcase or operation at extremely high crankcase temperatures.
  6. Inspect the air filter for dirt, sludge or damage. A hole in the filter element will allow unfiltered air to bypass into the air induction system. This can cause premature internal wear (engine dusting), allowing oil to escape past rings, pistons, valves and guides.
  7. If the engine is hot or was recently shut down, wait at least 5 minutes to allow the oil to drain back. Ask the customer if this requirement has been followed. Adding oil without this wait period can cause an overfill condition, leading to excessive oil consumption and foaming, which may cause engine damage.
  8. Make sure the oil level indicator (dipstick) is correctly and fully seated in the indicator tube. Remove the oil level indicator and record the oil level.

Detailed Pre-checks

  1. Check the thermostat opening temperature to make sure that the cooling system is operating at the specified temperature. If it is low, internal engine parts are not running at specified internal operating clearances.
  2. Verify the spark plugs are not oil saturated. Oil leaking into one or more cylinders will appear as an oil soaked condition on the plug. If a plug is saturated, a compression check may be necessary at the conclusion of the oil consumption test.

Post Checks, Evaluation and Corrective Action

  1. If test results indicate excessive oil consumption, carry out a cylinder compression test. The cylinder compression test should be carried out with a fully charged battery and all spark plugs removed. See the «COMPRESSION TEST CHART»(ref-375993-S31655312692010103100000) for pressure range limits.
  2. Compression should be consistent across all cylinders. Refer to the «COMPRESSION TESTING»(ref-375993-S31655312692010103100000) . If compression tested within the specifications found, the excessive oil consumption may be due to wear on the valve guides, valves or valve seals.
  3. A cylinder leak detection test can be carried out using a cylinder leakage tester. This can help identify valves, piston rings, or worn valve guides/valve stems, inoperative valve stem seals or other related areas as the source of oil consumption. NOTE: An oil-soaked appearance on the porcelain tips of the spark plugs also indicates excessive oil use. A typical engine with normal oil consumption will exhibit a light tan to brown appearance. See «SPARK PLUG ANALYSIS»(ref-375993-S23856608012010103100000) for details. A single or adjoining, multiple cylinder leak can be traced by viewing the tips.
  4. If an internal engine part is isolated as the root cause, determine if the repair will exceed cost limits and proceed with a repair strategy as required.
  5. Once corrective action to engine is complete and verifying that all pre-check items were eliminated in the original diagnosis, repeat the Oil Consumption Test as described above and verify consumption results.

Valve Train Analysis

The following component tests are used to diagnose valve train concerns.

Valve Train Analysis - Engine Off, Valve Cover Removed

Check for damaged or severely worn parts and correct assembly. Make sure correct parts are used with the static engine analysis as follows.

Valve Train Analysis - Camshafts and Valve Tappets

  1. Check for broken or damaged parts.
  2. Check for loose mounting bolts on camshaft caps.
  3. Check for worn or damaged valve tappets.

Valve Train Analysis - Valve Springs, Valve Tappets Removed

  1. Check for broken or damaged parts.

Valve Train Analysis - Valve Spring Retainer and Valve Spring Retainer Keys, Valve Tappets Removed

  1. Check for correct seating of the valve spring retainer key on the valve stem and in valve spring retainer.
  2. Check for correct seating on the valve stem.

Valve Train Analysis - Valves and Cylinder Head, Valve Tappets Removed

  1. Check for plugged oil drain-back holes.
  2. Check for worn or damaged valve tips.
  3. Check for missing or damaged valve stem seals or guide-mounted valve stem seal.
  4. Check for missing or worn valve spring seats.

Valve Train Analysis - Camshaft Lobe Lift

Check the lift of each camshaft lobe in consecutive order and make a note of the readings.

Scheme 2061

Scheme 2061: Valve Train Analysis - Camshaft Lobe Lift
  1. Remove the spark plugs. Refer to «ENGINE IGNITION - 3.5L GTDI/3.7L»(ref-376041) .
  2. Install the Dial Indicator Gauge with Holding Fixture so the rounded tip of the dial indicator is on top of the camshaft lobe and on the same plane as the valve tappet.
  3. Rotate the crankshaft using a breaker bar and socket attached to the crankshaft pulley retainer bolt. Rotate the crankshaft until the base circle of the camshaft lobe is reached.
  4. Zero the dial indicator. Continue to rotate the crankshaft until the high-lift point of the camshaft lobe is in the fully-raised position (highest indicator reading).
  5. To check the accuracy of the original dial indicator reading, continue to rotate crankshaft until the base circle is reached. The dial indicator reading should be zero. If zero reading is not obtained, repeat Steps 1 through 6.
  6. If the lift on any lobe is below specified service limits, install a new camshaft and camshaft roller followers.
  7. Install the spark plugs. Refer to «ENGINE IGNITION - 3.5L GTDI/3.7L»(ref-376041) .

Scheme 2062

Scheme 2062: Sprockets
  1. Inspect the sprockets for cracks and worn or chipped teeth.

Camshaft Bearing Journal Diameter

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2063

Scheme 2063: Camshaft Bearing Journal Diameter
  1. Measure each camshaft journal diameter in 2 directions.

Camshaft Journal to Bearing Clearance - OHC Engines

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2064

Scheme 2064: Camshaft Journal to Bearing Clearance - OHC Engines
  1. Measure each camshaft bearing in 2 directions. Subtract the camshaft journal diameter from the camshaft bearing diameter.

Crankshaft Main Bearing Journal Diameter

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2065

Scheme 2065: Crankshaft Main Bearing Journal Diameter
  1. Measure each of the crankshaft main bearing journal diameters in at least 2 directions.

Crankshaft Main Bearing Journal Taper and Out-of-Round

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2066

Scheme 2066: Crankshaft Main Bearing Journal Taper and Out-of-Round
  1. Measure each of the crankshaft main bearing journal diameters in at least 2 directions at each end of the main bearing journal.

Crankshaft Main Bearing Journal-to-Bearing Clearance

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Note. Crankshaft main bearing journals must be within specifications before checking journal clearance.

Scheme 2067

Scheme 2067: Crankshaft Main Bearing Journal-to-Bearing Clearance

Scheme 2068

Scheme 2068
  1. Remove the crankshaft main bearing caps and crankshaft main bearing.
  2. Lay a piece of Plastigage across the face of each crankshaft main bearing surface.
  3. Install and remove the crankshaft main bearing cap.
  4. Verify the crankshaft journal clearance.

Connecting Rod Bearing Journal Taper and Out-of-Round

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

  1. Measure the crankshaft connecting rod journal diameters in 2 directions perpendicular to one another at each end of the connecting rod journal. The difference in the measurements from one end to the other is the taper. Verify measurement is within the wear limit.

Cylinder Bore Taper

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2069

Scheme 2069: Cylinder Bore Taper
  1. Measure the cylinder bore at the top, middle and bottom of piston ring travel in 2 directions as indicated. Verify the cylinder bore is within the wear limit. The difference indicates the cylinder bore taper. Bore the cylinder to the next oversize limit.

Cylinder Bore Out-of-Round

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2070

Scheme 2070: Cylinder Bore Out-of-Round
  1. Measure the cylinder bore in 2 directions. The difference is the out-of-round.

Piston Pin Bore Diameter

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

  1. Measure the piston pin bore diameter in 2 directions on each side. Verify the diameter is within specification.

Piston Diameter

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2071

Scheme 2071: Piston Diameter
  1. Measure the piston diameter 90 degrees from the piston pin and 42 mm (1.65 in) down from the top of the piston at the point indicated.

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

  1. Measure the piston diameter 90 degrees from the piston pin and 42 mm (1.65 in) down from the top of the piston at the point indicated.

Piston To Cylinder Bore Clearance

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

  1. Subtract the piston diameter from the cylinder bore diameter to find the piston-to-cylinder bore clearance.

Piston Selection

Note. The cylinder bore must be within the specifications for taper and out-of-round before fitting a piston.

Scheme 2072

Scheme 2072
  1. Select a piston size based on the cylinder bore.
  2. Choose the piston with the correct paint color or specific size grade. Refer to the appropriate Engine article for the procedure.

Piston Pin Diameter

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2073

Scheme 2073: Piston Pin Diameter
  1. Measure the piston pin diameter in 2 directions at the points shown in illustration. Verify the diameter is within specification.

Connecting Rod Cleaning

Note. Do not use a caustic cleaning solution or damage to connecting rods can occur.

  1. Mark and separate the parts and clean with solvent. Clean the oil passages.

Connecting Rod Large End Bore

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2074

Scheme 2074: Connecting Rod Large End Bore
  1. Tighten the bolts to specification, then measure the bore in 2 directions. The difference is the connecting rod bore out-of-round. Verify the out-of-round is within specification.

Connecting Rod Bushing Diameter

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2075

Scheme 2075: Connecting Rod Bushing Diameter

Scheme 2076

Scheme 2076
  1. Use a telescoping gauge to determine the ID of the connecting rod bushing, if equipped.
  2. Measure the telescoping gauge with a micrometer. Verify the diameter is within specification.

Connecting Rod Bearing Journal-to-Bearing Clearance

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Note. The crankshaft connecting rod journals must be within specifications to check the connecting rod bearing journal clearance.

Scheme 2077

Scheme 2077: Connecting Rod Bearing Journal-to-Bearing Clearance

Scheme 2078

Scheme 2078
  1. Remove the connecting rod bearing cap.
  2. Position a piece of Plastigage across the bearing surface.
  3. Install and tighten to specifications, then remove the connecting rod bearing cap.
  4. Measure the Plastigage to get the connecting rod bearing journal clearance. The Plastigage should be smooth and flat. A changing width indicates a tapered or damaged connecting rod or connecting rod bearing.

Valve Stem Diameter

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2079

Scheme 2079: Valve Stem Diameter
  1. Measure the diameter of each intake and exhaust valve stem at the points shown in illustration. Verify the diameter is within specification.

Scheme 2080

Scheme 2080: Valve Inspection
  1. Inspect the following valve areas: The end of the stem for grooves or scoring. The valve face and the edge for pits, grooves or scores. The valve head for signs of burning, erosion, warpage and cracking. The valve margin for wear.

Valve Guide Inner Diameter

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2081

Scheme 2081: Valve Guide Inner Diameter
  1. Use a ball gauge to determine the inside diameter of the valve guides in 2 directions at the top, middle and bottom of the valve guide.
  2. Measure the ball gauge with a micrometer.
  3. If the valve guide is not within specifications, install a new cylinder head assembly.

Valve Spring Installed Length

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2082

Scheme 2082: Valve Spring Installed Length
  1. Measure the installed length of each valve spring.

Valve Spring Free Length

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2083

Scheme 2083: Valve Spring Free Length
  1. Measure the free length of each valve spring.

Scheme 2084

Scheme 2084: Valve Spring Squareness
  1. Measure the out-of-square on each valve spring. Turn the valve spring and observe the space between the top of the valve spring and the square.

Valve and Seat Refacing Measurements

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Note. After grinding valves or valve seats, check valve clearance.

Scheme 2085

Scheme 2085: Valve and Seat Refacing Measurements
  1. Check the valve head and seat. Check valve angles. Check margin width. Be sure margin width is within specification.
  2. Inspect for abnormalities on the valve face and seat. Install a new cylinder head assembly if abnormalities are found.

Valve Seat Width

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2086

Scheme 2086: Valve Seat Width
  1. Measure the valve seat width. If necessary, grind the valve seat to specification. Measure the intake valve seat width. Measure the exhaust valve seat width. Recheck the valve spring installed length after the seats have been ground, and shim the valve springs as necessary to achieve the correct installed spring length.

Valve Seat Runout

Note. Refer to the appropriate ENGINE - 3.5L GTDI or ENGINE - 3.7L for the specification.

Scheme 2087

Scheme 2087: Valve Seat Runout
  1. Use a valve seat runout gauge to check valve seat runout.

Scheme 2088

Scheme 2088: Flexplate Inspection
  1. Inspect the flexplate for: any cracks. worn ring gear teeth. chipped or cracked ring gear teeth.
ItemSpecification
Motorcraft® SAE 5W-20 Premium Synthetic Blend Motor Oil XO-5W20-QSP (US); Motorcraft® SAE 5W-20 Super Premium Motor Oil CXO-5W20-LSP12 (Canada); or equivalentWSS-M2C930-A

MATERIAL CHART

  1. Clean the cylinder bores with soap or detergent and water.
  2. Thoroughly rinse with clean water and wipe dry with a clean, lint-free cloth.
  3. Use a clean, lint-free cloth and lubricate the cylinder bores. Use clean engine oil meeting Ford specification.

Scheme 2089

Scheme 2089: Bearing Inspection
  1. Inspect bearings for the following defects: Cratering - fatigue failure Spot polishing - incorrect seating Imbedded dirty engine oil Scratching - dirty engine oil Base exposed - poor lubrication Both edges worn - journal damaged One edge worn - journal tapered or bearing not seated
ItemSpecification
Threadlock 262 TA-26WSK-M2G351-A6

MATERIAL CHART

All core plugs

  1. Use the Slide Hammer and a freeze plug remover to remove the core plug.
  2. Inspect the core plug bore for any damage that would interfere with the correct sealing of the plug. If the core plug bore is damaged, bore for the next oversize plug. Cup-type
  3. Coat the cup-type core plug and bore lightly with sealant and install the core plug using a freeze plug installer. Expansion-type
  4. Coat the expansion-type core plug and bore lightly with sealant and install the core plug using a freeze plug installer.

Scheme 2090

Scheme 2090: Spark Plug Inspection

Scheme 2091

Scheme 2091

Scheme 2092

Scheme 2092

Scheme 2093

Scheme 2093

Scheme 2094

Scheme 2094

Scheme 2095

Scheme 2095

Scheme 2096

Scheme 2096
  1. Inspect the spark plug for a bridged gap. Check for deposit build-up closing the gap between the electrodes. Deposits are caused by oil or carbon fouling. Install a new spark plug.
  2. Check for oil fouling. Check for wet, black deposits on the insulator shell bore electrodes, caused by excessive oil entering the combustion chamber through worn rings and pistons, excessive valve-to-guide clearance or worn or loose bearings. Correct the oil leak concern. Install a new spark plug.
  3. Inspect for carbon fouling. Look for black, dry, fluffy carbon deposits on the insulator tips, exposed shell surfaces and electrodes, caused by a spark plug with an incorrect heat range, dirty air cleaner, too rich a fuel mixture or excessive idling. Install new spark plugs.
  4. Inspect for normal burning. Check for light tan or gray deposits on the firing tip.
  5. Inspect for pre-ignition, identified by melted electrodes and a possibly damaged insulator. Metallic deposits on the insulator indicate engine damage. This may be caused by incorrect ignition timing, wrong type of fuel or the unauthorized installation of a heli-coil insert in place of the spark plug threads. Install a new spark plug.
  6. Inspect for overheating, identified by white or light gray spots and a bluish-burnt appearance of electrodes. This is caused by engine overheating, wrong type of fuel, loose spark plugs, spark plugs with an incorrect heat range, low fuel pump pressure or incorrect ignition timing. Install a new spark plug.
  7. Inspect for fused deposits, identified by melted or spotty deposits resembling bubbles or blisters. These are caused by sudden acceleration. Install new spark plugs.

Scheme 2097

Scheme 2097: Valve Tappet Inspection
  1. Inspect the valve tappet for damage, especially in the indicated areas. If any damage is evident, inspect the camshaft lobes and valves for damage. Install new components as necessary.

Powertrain/Drivetrain Mount Neutralizing

Note. Refer to the appropriate information and procedure for special instructions on loosening and tightening mount fasteners.

  1. With the vehicle in NEUTRAL, position it on a hoist. For additional information, refer to «JACKING & LIFTING»(ref-375987) .
  2. Loosen, but do not remove, the powertrain/drivetrain mount fasteners.
  3. Lower the vehicle.
  4. Start the vehicle and move it in forward 0.6-1.2 m (2-4 ft). Then move the vehicle in reverse the same distance.
  5. Raise and support the vehicle.
  6. Tighten the powertrain/drivetrain mount fasteners.
  7. Lower the vehicle.
  8. Test the system for normal operation.