Engine System-General Information: Other Mercury Montego III

Engine Oil Leaks

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 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. Clean the engine with a suitable solvent to remove all traces of oil.
2. Add Gasoline Engine Oil Dye 164-R3705 to the engine oil. Use a minimum 14.8 ml (0.5 ounce) to a maximum 40 ml (1.35 ounce) of fluorescent additive to all engines.
3. 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 necessary for the leak to appear.

Leakage Points - Underhood

Examine the following areas for oil leakage

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

Compression Pressure Limit Chart

COMPRESSION PRESSURE LIMIT CHART

If one or more cylinders reads low, squirt approximately one tablespoon of engine oil meeting Ford specification on top of the pistons in the low-reading cylinders. Repeat the compression pressure check on these cylinders.

Cylinder Leakage Detection

When a cylinder produces a low reading, use of the Engine Cylinder Leak Detection/Air Pressurization Kit will be helpful in pinpointing the exact cause.

The leakage detector is inserted in the spark plug hole, the piston is brought up to top dead center on the compression stroke, and compressed air is admitted.

Once the combustion chamber is pressurized, a special gauge included in the kit will read the percentage of leakage. Leakage exceeding 20 percent 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 tailpipe. Leakage past the piston rings will be audible at the positive crankcase ventilation (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, 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 Guide. 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 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 portion of this section.
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 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 past 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 in this section for pressure range limits.
2. Compression should be consistent across all cylinders. For additional information, refer to «Compression Test - Compression Gauge Check»(ref-233008-S12621303832006052400000) . If compression tested within the specifications found in this section, 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 indicates excessive oil use. A typical engine with normal oil consumption will exhibit a light tan to brown appearance. See «Spark Plug Inspection»(ref-233008-S30583830892006052400000) 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 all pre-check items were eliminated in the original diagnosis, repeat the «Oil Consumption Test»(ref-233008-S02886180582006052400000) as described above to 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 - Engine Off

1. Check for loose mounting bolts on camshaft caps.
2. Check valve shim to camshaft gap.

Valve Train Analysis - Engine Off, Camshaft - Engines

1. Check for broken or damaged parts.

Valve Train Analysis - Valve Springs

1. Check for broken or damaged parts.

Valve Train Analysis - Engine Off, 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 - Engine Off, 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 or guide-mounted valve stem seal.
4. Check valve tappet shim gap.
5. Check for missing or worn valve spring seats.
6. Check for plugged oil metering orifice in cylinder head oil reservoir (if equipped).

Static checks (engine off) are to be made on the engine prior to the dynamic procedure.

Valve Train Analysis - Engine Off, Camshaft Lobe Lift - OHC Engines

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

Scheme 298

1. Remove the valve covers.
2. Remove the spark plugs.
3. Install the special tool so the rounded tip of indicator is on top of the camshaft lobe and on the same plane as the valve tappet.
4. 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.
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 indicator reading).
6. To check the accuracy of the original indicator reading, continue to rotate crankshaft until the base circle is reached. The indicator reading should be zero. If zero reading is not obtained, repeat Steps 1 through 6.
7. Install the spark plugs.
8. Install the valve covers.

Valve Train Analysis - Engine Off, Valve Tappet

Valve tappet noise can be caused by any of the following

1. Excessive valve tappet shim gap
2. Excessive valve guide wear

Excessive collapsed valve tappet shim gap can be caused by incorrect initial adjustment or wear of valve tappet shim face.

For additional information, refer to the valve train shim and gap inspection procedure in the appropriate engine section.

Scheme 299

1. Inspect the timing chain/belt and the sprocket. Install new components as necessary. Refer to the appropriate engine article for the procedure.

Scheme 300

1. Measure each camshaft journal diameter in 2 directions. If out of specification, install new components as necessary. Refer to the appropriate engine article for the procedure.

Valve and Seat Refacing Measurements

Scheme 301

1. Check the valve head and seat. Check valve angles. Check margin width. Refer to the appropriate engine article for the procedure. 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.

Material

MATERIAL

Scheme 302

1. Use a slide hammer or tools suitable to remove the cylinder block core plug.
2. Inspect the cylinder block plug bore for any damage that would interfere with the correct sealing of the plug. If the cylinder block plug bore is damaged, bore for the next oversize plug.
3. Coat the cylinder block core plug and bore lightly with Threadlock 262 and install the cylinder block core plug.

Cup-Type

1. Use a tool suitable to seat the cup-type cylinder block core plug.

Expansion-Type

1. Use tool suitable to seat the expansion-type cylinder block core plug.

Scheme 303

Scheme 304

Scheme 305

Scheme 306

Scheme 307

Scheme 308

Scheme 309

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. Clean the 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 fused deposits, identified by melted or spotty deposits resembling bubbles or blisters. These are caused by sudden acceleration. Install new spark plugs.
7. Inspect for overheating, identified by white or light gray spots and with 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.

Scheme 310

Scheme 311

1. Inspect the roller follower for flat spots or scoring. If any damage is found, inspect the camshaft lobes and hydraulic lash adjuster for damage.