Engine System - General Information: Other Ford Ranger II рестайлинг

Material

MATERIAL SPECIFICATION

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. If an overnight drive is done, the fan air or road air blast can cause erroneous readings.

Note. When diagnosing engine oil leaks, the source and location of the leak must be positively identified prior to repair.

Prior to carrying out this procedure, clean all sealing surface areas 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 fluorescent additive 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. If the oil is not premixed, the fluorescent additive 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 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 12 Volt Master UV Diagnostic Inspection 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 the 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. Intake manifold gaskets
3. Cylinder head gaskets
4. Oil filter
5. Oil filter adapter
6. Engine front cover
7. Oil filter adapter and filter body
8. Oil level indicator tube connection
9. Oil pressure sensor

Leakage Points - Under Engine - With Vehicle on Hoist

Examine the following areas for oil leakage

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

Leakage Points - With Transmission and Flywheel Removed

Examine the following areas for oil leakage

1. Crankshaft rear seal
2. Rear main bearing cap parting line
3. Rear main bearing cap and seals
4. Flywheel mounting bolt holes (with flywheel installed)
5. Camshaft rear bearing covers or 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 during the compression test, 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 dead center 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. A leak at the exhaust valve can be heard at the tail pipe. 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 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»(ref-365375-S11190883832010070700000) .
4. Inspect the crankcase ventilation system for: disconnected hoses at the valve cover or throttle body. 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 passage 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 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 - Test Results»(ref-365375-S16019196602010070700000) for pressure range limits.
2. Compression should be consistent across all cylinders. Refer to the «COMPRESSION TEST - Test Results»(ref-365375-S16019196602010070700000) . 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 an Engine Cylinder Leak Detection/Air Pressurization Kit. 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 indicate excessive oil use. A typical engine with normal oil consumption will exhibit a light tan to brown appearance. See «Spark Plug Inspection»(ref-365375-S34256498032010070700000) 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 the engine is complete and verification 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 - 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

1. Check for broken or damaged parts.
2. Check for loose mounting bolts on camshaft caps.

Valve Train Analysis - Camshaft Roller Followers and Hydraulic Lash Adjusters, 4.0L SOHC Engines

1. Check for loose mounting bolts on camshaft carriers.
2. Check for plugged oil feed in the camshaft roller followers, lash adjusters or cylinder heads.
3. Check for collapsed hydraulic lash adjusters.

Valve Train Analysis - Valve Springs

1. Check for broken or damaged parts.

Valve Train Analysis - Valve Spring Retainer and Valve Spring Retainer Keys

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

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.
4. Check collapsed valve tappet gap.
5. Check installed valve spring height.
6. Check for missing or worn valve spring seats.
7. Check for plugged oil drain back holes.

Valve Train Analysis - Camshaft Lobe Lift, 2.3L

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

Scheme 561

1. Remove the valve cover. Refer to «ENGINE - 2.3L»(ref-365364) .
2. Remove the spark plugs. Refer to «ENGINE IGNITION - 2.3L»(ref-365418) .
3. Install the Dial Indicator Gauge with Holding Fixture so the rounded tip of indicator is on top of the camshaft lobe.
4. Rotate the crankshaft using a breaker bar and a socket attached to the crankshaft pulley bolt. Rotate the crankshaft until the base circle of the camshaft lobe is reached. Typical Engine With Valve Tappets
5. 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 indicated reading).
6. To check the accuracy of the original indicator reading, continue to rotate the crankshaft until he vase circle is reached. The indicator reading should be zero. If a zero reading is not obtained, repeat the measurement.
7. If the lift on any camshaft lobe is below specified service limits, install a new camshaft and valve tappets. Refer to «ENGINE - 2.3L»(ref-365364) .
8. Install the spark plugs. Refer to «ENGINE IGNITION - 2.3L»(ref-365418) .
9. Install the valve cover. Refer to «ENGINE IGNITION - 2.3L»(ref-365418) .

Valve Train Analysis - Camshaft Lobe Lift, 4.0L SOHC Engines

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

Scheme 562

1. Remove the valve covers. Refer to «ENGINE - 4.0L SOHC»(ref-365365) .
2. Remove the spark plugs. Refer to «ENGINE IGNITION - 4.0L SOHC»(ref-365419) .
3. Install the Dial Indicator Gauge with Holding Fixture so the rounded tip of indicator is on top of the camshaft lobe.
4. Rotate the crankshaft using a breaker bar and socket attached to the crankshaft pulley bolt. Rotate the crankshaft until the base circle of the camshaft lobe is reached. Typical Engine With Camshaft Roller Followers
5. Zero the Dial Indicator. Continue to rotate the crankshaft until the (1) high-lift point of the camshaft lobe is in the fully-raised position (highest indicator reading).
6. To check the accuracy of the original indicator reading, continue to rotate crankshaft until the (2) base circle is reached. The indicator reading should be zero. If zero reading is not obtained, repeat the measurement.
7. If the lift on any lobe is below specified service limits, install a new camshaft, and new camshaft roller followers. Refer to «ENGINE - 4.0L SOHC»(ref-365365) .
8. Install the spark plugs. Refer to «ENGINE IGNITION - 4.0L SOHC»(ref-365419) .
9. Install the valve covers. Refer to «ENGINE - 4.0L SOHC»(ref-365365) .

Valve Train Analysis - Hydraulic Lash Adjusters

Hydraulic lash adjuster noise can be caused by any of the following

1. Excessive hydraulic lash adjuster gap (collapsed)
2. Incorrectly functioning hydraulic lash adjuster
3. Air in lubrication system
4. Excessive valve guide wear
5. Low oil pressure

Excessive collapsed hydraulic lash adjuster gap can be caused by loose rocker arm seat bolts/nuts, incorrect initial adjustment or wear of hydraulic lash adjuster face, or worn roller hydraulic lash adjuster, push rod, rocker arm, rocker arm seat or valve tip. With hydraulic lash adjuster collapsed, check gap between the valve tip and the rocker arm to determine if any other valve train parts are damaged, worn or out of adjustment.

An incorrectly functioning hydraulic lash adjuster can be sticking, caused by contaminants or varnish inside the hydraulic lash adjuster. The hydraulic lash adjuster can have a check valve that is not functioning correctly, which can be caused by an obstruction, such as dirt or chips that prevent the check valve from closing, or a broken check valve spring. A hydraulic lash adjuster with a leakdown time out of specification can cause hydraulic lash adjuster noise. If no other cause for noisy hydraulic lash adjuster can be found, the leakdown rate should be checked and new hydraulic lash adjusters installed if found to be out of specification.

Assembled hydraulic lash adjusters can be tested with a commercially available leakdown tester to check the leakdown rate. The leakdown rate specification is the time in seconds for the plunger to move a specified distance while under a 22.7 kg (50 lb) load.

Air bubbles in the lubrication system will prevent the hydraulic lash adjuster from supporting the valve spring load. This can be caused by too high or too low an oil level in the oil pan or by air being drawn into the system through a hole, crack or leaking gasket on the oil pump screen cover and tube.

Scheme 563

1. Inspect the sprockets for cracks and worn or chipped teeth.

Camshaft Bearing Journal Diameter

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

Scheme 564

1. Measure each camshaft journal diameter in 2 directions.

Camshaft Journal to Bearing Clearance - OHC Engines

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

Scheme 565

1. NOTE: The camshaft journals must meet specifications before checking camshaft journal clearance. 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 - 2.3L or ENGINE - 4.0L SOHC for the specification.

1. Measure each of the crankshaft main bearing journal diameters in at least 2 directions.

Scheme 566

Crankshaft Main Bearing Journal Taper and Out-of-Round

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

1. Measure each of the crankshaft main bearing journal diameters in at least 2 directions at each end of the main bearing journal.

Scheme 567

Crankshaft Main Bearing Journal-to-Bearing Clearance

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

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

Scheme 568

Scheme 569

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. NOTE: Do not turn the crankshaft while carrying out this procedure. 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 - 2.3L or ENGINE - 4.0L SOHC 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 - 2.3L or ENGINE - 4.0L SOHC for the specification.

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.

Scheme 570

Cylinder Bore Out-of-Round

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

1. Measure the cylinder bore in 2 directions. The difference is the out-of-round.

Scheme 571

Piston Pin Bore Diameter

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

Scheme 572

1. NOTE: Piston and piston pins are a matched set and should not be interchanged. 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 - 2.3L or ENGINE - 4.0L SOHC 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.

Scheme 573

Piston To Cylinder Bore Clearance

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

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

Piston Pin Diameter

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

1. Measure the piston pin diameter in 2 directions at the points shown in illustration. Verify the diameter is within specification.

Scheme 574

Connecting Rod Cleaning

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

Scheme 575

1. NOTE: The connecting rod large end is a matched set. The connecting rod cap must be installed on the original connecting rod in the original position. Do not reverse the cap. Parts are not interchangeable. Mark and separate the parts and clean with solvent. Clean the oil passages.

Connecting Rod Large End Bore

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

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.

Scheme 576

Connecting Rod Bushing Diameter

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

Scheme 577

Scheme 578

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 - 2.3L or ENGINE - 4.0L SOHC for the specification.

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

Scheme 579

1. Remove the connecting rod bearing cap.
2. Position a piece of Plastigage across the bearing surface.
3. NOTE: Do not turn the crankshaft during this step. 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.

Scheme 580

Valve Stem Diameter

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

1. Measure the diameter of each intake and exhaust valve stem at the points shown in illustration. Verify the diameter is within specification.

Scheme 581

Valve Guide Inner Diameter

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

Scheme 582

Scheme 583

1. NOTE: Valve guides tend to wear in an hourglass pattern. The ball gauge can be inserted into the combustion chamber side of the valve guide, if necessary. 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 - 2.3L or ENGINE - 4.0L SOHC for the specification.

1. Measure the installed length of each valve spring.

Scheme 584

Valve Spring Free Length

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

1. Measure the free length of each valve spring.

Scheme 585

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.

Scheme 586

Valve and Seat Refacing Measurements

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

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

Scheme 587

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 - 2.3L or ENGINE - 4.0L SOHC for the specification.

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.

Scheme 588

Valve Seat Runout

Note. Refer to the appropriate ENGINE - 2.3L or ENGINE - 4.0L SOHC for the specification.

1. Use a valve seat runout gauge to check valve seat runout.

Scheme 589

MATERIAL SPECIFICATION

1. NOTE: If these procedures are not followed, rusting of the cylinder bores may occur. 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.

MATERIAL SPECIFICATION

Note. It is necessary to use Loctite® Retaining Compound 620 High Temperature sealant on all 3 valve modular engine cylinder head cup plugs. If not used, the cylinder head cup plugs could leak or seep, causing serious engine damage.

Note. Use threadlock 262 on all other applications.

All core plugs

Scheme 590

Scheme 591

Scheme 592

1. NOTE: Cylinder block core plug shown in illustration, cylinder head core plug similar. Use the Slide Hammer and a freeze plug remover to remove the core plug.
2. NOTE: Oversize plugs are identified by the OS stamped in the flat located on the cup side of the plug. 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. NOTE: Use care during this procedure so as not to disturb or distort the cup sealing surface. NOTE: When installed, the flanged edge must be below the chamfered edge of the bore to effectively seal the bore. Coat the cup-type core plug and bore lightly with sealant and install the core plug using a freeze plug installer. Expansion-type
4. NOTE: Do not contact the crown when installing an expansion-type core plug. This could expand the plug before seating and result in leakage. Coat the expansion-type core plug and bore lightly with sealant and install the core plug using a freeze plug installer.

Scheme 593

Scheme 594

Scheme 595

Scheme 596

Scheme 597

Scheme 598

Scheme 599

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.

Powertrain/Drivetrain Mount Neutralizing

Note. Refer to the appropriate service 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 AND LIFTING»(ref-365369) .
2. Loosen, but do not remove, the powertrain/drivetrain mount fasteners.
3. Lower the vehicle.
4. NOTE: Do not twist or strain the powertrain/drivetrain mounts or damage to the mounts may occur. 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.