2.5l 4-cyl - VIN [d] Ford Taurus I

ENGINE IDENTIFICATION

Note. For engine repair procedures not covered in this article, see ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION article in the GENERAL INFORMATION section.

Engine may be identified by the Vehicle Identification Number (VIN) at top of instrument panel near windshield on left side of vehicle and visible from outside. VIN number is also stamped on Safety Certification Decal on left front door lock face panel and on Engine Identification Label on valve cover.

The VIN number contains 17 characters. The 8th character identifies the engine and the 10th character identifies the model year. To determine if the engine is High Swirl Combustion (HSC) or High Swirl Output (HSO), use the emission calibration number label located on the drivers door or pillar.

ENGINE IDENTIFICATION CODES

Removal

1. Relieve fuel system pressure by disconnecting electrical connector at inertia switch, then cranking engine for 15 seconds. On ATX automatic transaxle equipped models, remove timing window cover at transaxle and rotate engine until flywheel timing marker is aligned with timing pointer. Mark crankshaft pulley at 12 o'clock position (TDC). Rotate crankshaft pulley mark to 6 o'clock position.
2. On all models, disconnect battery negative cable. Mark hood hinge position and remove hood. Remove air cleaner assembly. Drain cooling system. Remove upper radiator hose at engine. Remove all wiring and vacuum lines as necessary.
3. Disconnect crankcase ventilation hose at valve cover and intake manifold. Remove fuel lines at throttle body. Disconnect ground wire at engine. Remove accelerator cable and throttle valve control cable at throttle body. Discharge air conditioning system and remove pressure and suction lines from compressor (if equipped).
4. On manual transaxle equipped models, remove engine damper brace. On all models, remove drive belt, water pump pulley, and air cleaner-to-canister hose. Raise and support vehicle. Drain engine oil and remove oil filter. Disconnect starter cable and remove starter motor.
5. On automatic transaxle equipped models only, remove converter nuts and position mark previously made on crankshaft pulley as close to 6 o'clock position (BDC) as possible with converter stud visible. NOTE: Flywheel timing marker must be in 6 o'clock (BDC) position for proper engine removal.
6. Remove engine insulator nuts. Disconnect exhaust pipe from manifold. Remove canister bracket and halfshaft bracket from engine. Remove lower engine-to-transmission attaching bolts. Remove engine from vehicle.

Installation

To install, reverse removal procedure. Check fluid levels. Start engine and check for leaks.

1. Disconnect negative battery cable. Drain cooling system. Remove air cleaner assembly. Remove heat stove tube at heat shield. Disconnect throttle cable. Mark and remove vacuum lines and electrical connectors.
2. Remove 3 nuts attaching exhaust manifold-to-inlet pipe. Remove exhaust manifold heat shield assembly. Disconnect oxygen sensor. Disconnect throttle linkage. Remove thermactor check valve hose at tube. Remove EGR and bracket. Disconnect coolant inlet tube at intake manifold.
3. On all models, mark and disconnect fuel lines to carburetor. Remove heater hose at fitting located under intake manifold. Remove intake manifold bolts and stud. Remove intake manifold. Remove exhaust manifold bolts. Remove exhaust manifold.

Inspection

Clean and check gasket mating surface. Check surfaces for warpage. Intake and exhaust manifold warpage should not exceed .005" (.12 mm) overall. Cylinder head mating surface should not exceed .007" (.18 mm) warpage overall.

1. Position exhaust manifold on cylinder head with Exhaust Manifold Alignment Studs (T84P-6065-B) in holes No. 2 and 3. (Scheme 2) Install attaching bolts in remaining holes. Remove guide studs and install bolts. Tighten exhaust manifold bolts in 2 steps and sequence. (Scheme 2)
2. Coat new intake manifold gasket with sealer. Position intake manifold and gasket on cylinder head. Tighten bolts to specifications and in sequence. (Scheme 1) To complete installation, reverse removal procedure. Tighten all bolts/nuts to specifications.

Intake Manifold Tightening Sequence. Scheme 1

Exhaust Manifold Tightening Sequence. Scheme 2

1. Remove negative battery cable. Drain cooling system at lower radiator hose. Disconnect heater hose at fitting located under intake manifold. Disconnect upper radiator hose at cylinder head. Remove air cleaner assembly.
2. Mark and disconnect vacuum lines. Disconnect electric cooling fan switch. Mark and disconnect spark plug wires at spark plugs. Remove distributor cap with wires. Remove accessory drive belts, alternator and mounting bracket from cylinder head.
3. Remove PCV hose. Remove valve cover. Disconnect fuel supply and return lines. Disconnect throttle cable. Disconnect EGR tube at EGR valve. Remove choke cap wire. Raise vehicle. Remove exhaust inlet pipe from exhaust manifold. Disconnect oxygen sensor. Lower vehicle.
4. Remove rocker arm bolts. Keep all components in order to ensure installation to original location. Remove fulcrums and rocker arms. Remove push rods.
5. Remove cylinder head bolts. Remove cylinder head with intake and exhaust manifolds attached. DO NOT lay cylinder head flat. Damage to spark plugs and/or gasket surface may result.

Clean combustion chambers before disassembly of cylinder head. Clean gasket mating surfaces. Check cylinder head for warpage. Warpage limit is .003" (.08 mm) in any 6". Overall cylinder head warpage is less than .007" (.18 mm). Clean and tap cylinder head bolt holes in cylinder block.

Note. Cylinder head bolts on intake/exhaust side are longer than spark plug side of cylinder head.

1. Use 2 old cylinder head bolts and cut the head off, to use as guide pins. Slot top of old bolts for screwdriver access. Install fabricated guide pins in Nos. 7 and 10 hole. (Scheme 3) Coat new head gasket with sealer and install gasket. Ensure marked side of gasket is in proper position.
2. Position cylinder head through guide pins and install cylinder head. Install cylinder head bolts until snug. Remove 2 guide pins and install 2 cylinder head bolts. Tighten cylinder head bolts in 2 steps and sequence. (Scheme 3)
3. Align crankshaft sprocket timing mark with camshaft sprocket timing mark. Install push rods, rocker arms and fulcrums on No. 1 intake and exhaust, No. 2 intake and No. 3 exhaust. Tighten rocker arm bolts to specifications. Completely collapse lifter by applying pressure on push rod before rotating engine.
4. Rotate crankshaft 180 degrees. Install push rods, rocker arms and fulcrums on No. 2 exhaust, No. 3 intake and No. 4 intake and exhaust. Tighten rocker arm bolts to specifications. Completely collapse lifters and rotate crankshaft 180 degrees.
5. To complete installation, reverse removal procedure. Tighten all bolts/nuts to specifications. Change oil and filter. Fill fluid levels. Start engine and check for leakage.

Cylinder Head Tightening Sequence. Scheme 3

CAMSHAFT FRONT COVER & TIMING CHAIN REMOVAL & INSTALLATION

Note. Front cover, front oil seal and camshaft procedures can only be performed with engine removed from vehicle.

1. With engine and transaxle removed as an assembly, remove oil dipstick. Remove accessory drive belts. Remove crankshaft damper bolt and washer. Remove crankshaft damper with Remover (T77F-4220-B). Remove front cover oil seal using Seal Remover (T74P-6700-A). Remove bolts from front cover and necessary oil pan bolts.
2. Pry top of front cover away from cylinder block. Remove front cover and gasket. Check timing chain and components. See INSPECTION below. Align camshaft sprocket and crankshaft sprocket timing marks. Remove camshaft sprocket retaining bolt and washer. Slide camshaft sprocket, crankshaft sprocket and timing chain assembly forward. Remove as an assembly.

1. Clean gasket mating surfaces. Check timing chain tensioner blade for wear. Check timing chain vibration damper for wear, located inside front cover. Check timing chain deflection by rotating crankshaft counterclockwise to take up slack on left side of chain. Mark a reference point on cylinder block and measure from this point to chain.
2. Move crankshaft in opposite direction to take up slack on right side of chain. Force left side of chain out with fingers. Measure distance between reference point and chain. The difference between the 2 measurements is the deflection. If the deflection is not within specifications, replace components as necessary. Refer to the «TIMING CHAIN SPECIFICATIONS»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) table.

TIMING CHAIN SPECIFICATIONS

1. Clean and inspect components before installation. Align camshaft sprocket and crankshaft sprocket timing marks. Slide timing chain and sprockets into position. Install camshaft bolt and washer. Ensure flat side of washer faces camshaft sprocket.
2. Oil timing chain, sprockets and tensioner after installation. Apply Sealing Compound (B5A-19554-A) to new front cover gasket and position gasket on cover. DO NOT install front cover oil seal until cover is installed on block.
3. Install Front Cover Aligner (T84P-6019-C) on crankshaft. Install front cover and gasket. Install front cover bolts and tighten to specifications. Remove aligner.
4. Coat hub of crankshaft with Polyethylene Grease (DOAZ-19584-A). Using Pinion Seal Installer (T83T-4676-A), install new front cover seal. To complete installation, reverse removal procedure. Tighten bolts/nuts to specification. Fill fluid levels and check for leakage.

1. Remove engine and transaxle. Drain engine oil. Remove accessory belts and pulleys. Remove cylinder head. See «CYLINDER HEAD»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) . Position No. 1 cylinder on TDC. Mark spark plug wires and remove from spark plugs. Remove distributor cap and wires. Mark distributor-to-engine and remove distributor assembly.
2. Using a magnet, remove lifters. Keep in order of removal to ensure lifters are installed to original location. Remove front cover. See «CAMSHAFT FRONT COVER & TIMING CHAIN REMOVAL & INSTALLATION»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d__camshaft-front-cover-timing-chain) . Check camshaft end play. See «CAMSHAFT END PLAY»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d__camshaft-end-play) .
3. Remove timing chain and sprockets as an assembly. See «CAMSHAFT FRONT COVER & TIMING CHAIN REMOVAL & INSTALLATION»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d__camshaft-front-cover-timing-chain) . Remove tensioners. Remove camshaft thrust plate. Pull camshaft out front of engine, using care not to damage journals or bearings.

Clean all components and gasket mating surfaces. Check clearance of camshaft-to-bearings. Check lift of each lobe in consecutive order and record each reading. See CAMSHAFT LOBE LIFT .

Coat camshaft lobes and journals with SAE 50 engine oil. Slide camshaft in through front of block. Install thrust plate. Ensure camshaft turns freely. To complete installation, reverse removal procedure. To install push rods and rocker arm assemblies, see step 3) in INSTALLATION under CYLINDER HEAD . Tighten all bolts/nuts to specifications.

CAMSHAFT BEARINGS

Note. Camshaft bearings are prefinished to size. No reaming is required for standard or .015" undersize journal diameters.

Remove engine, camshaft, crankshaft, and rear bearing bore plug. Using Camshaft Bearing Replacer (T65L-5260-A) and instructions, remove camshaft bearings. Install camshaft bearings with replacer. Ensure oil holes in bearings and block are aligned. Install new rear bearing bore plug. To complete installation, reverse removal procedure.

CAMSHAFT END PLAY

Position dial indicator point on camshaft sprocket. Pry camshaft fully rear and zero indicator. Pry camshaft fully forward and note dial indicator reading. Replace thrust plate if not within specifications. Camshaft end play must be .009" (.23 mm).

CAMSHAFT LOBE LIFT

1. Camshaft lobe lift can be checked with camshaft installed or removed. Check camshaft lobe lift in consecutive order and record readings. With camshaft removed, measure distance between major and minor diameters of each lobe. The difference in reading is lobe lift.
2. With camshaft installed, remove valve cover. Remove rocker arm bolt. Remove fulcrum and rocker arm. Install a dial indicator, with a cup shaped pointer, on top of cylinder head. Place push rod in cup shaped pointer in same plane as push rod movement.
3. Install remote starter and leave ignition switch off. Use remote starter and rotate crankshaft until push rod is in lowest position. Zero dial indicator. Rotate crankshaft slowly until push rod is in fully raised position. Record reading and repeat procedure for remaining lobes. Replace camshaft and lifters if not within specifications. See «ENGINE SPECIFICATIONS»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) tables.

Front-To-Rear

I-E-I-E-E-I-E-I.

VALVE SEATS

Note. Valve seat replacement information not available at time of publication.

Refacing

Use only a 60 degree angle grinding stone to remove stock from bottom of all seats. Use a 30 degree angle grinding stone to remove stock from top of all seats. Valve seat must be a true 45 degree finished angle. Intake seat width should be .080" (2.03 mm) and exhaust seat width should be .090" (2.29 mm).

1. Mark all components prior to removal for installation reference. Thoroughly clean cylinder head and valves, using care not to damage surfaces. Remove valves. Check valve-to-guide clearance of each valve in its respective valve guide.
2. Install a valve and hold against seat. Install Valve Stem Clearance Tool (T65T-6505-H) on valve stem, until it is fully seated. Tighten tool set screw firmly. Allow valve to drop away from seat and tool to contact upper guide surface.
3. Install dial indicator with pointer against center portion of tool. (Scheme 4) Move clearance tool back and forth in-line with dial indicator pointer. Keep clearance tool on upper guide surface. Record dial indicator reading.
4. Divide dial indicator reading by 2. This total is the valve-to-guide clearance. If not within specifications, replace valve(s) with next available oversize valve. Ream valve guide until clearance with valve is within specification. Refer to appropriate «ENGINE SPECIFICATIONS»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) tables.

Valve-To-Guide Clearance. Scheme 4

Inspect valve springs for cracks or damage. Measure installed height. Installed height should be 1.49" (37.9 mm). Measure free length and out-of-square. Maximum out-of-square is .060" (1.52 mm). Check spring tension at a specified length. See ENGINE SPECIFICATIONS tables. Replace springs as necessary.

HYDRAULIC LIFTER

Before replacing a hydraulic lifter for noisy operation, ensure the noise is not caused by improper collapsed lifter gap, worn rocker arms, push rods, or valve tips.

Remove cylinder head and related parts. Using a magnet, remove lifters. Place lifters in a rack so they can be installed in original positions. If the lifters are stuck in their bores by excessive varnish or gum, it may be necessary to use Hydraulic Lifter Puller T70L-6500-A or equivalent to remove the lifters. Rotate the lifter back and forth to loosen any gum and varnish which may have formed. Keep the assemblies intact until they are to be cleaned.

If a hydraulic lifter has been disassembled and cleaned, ensure to fill it with test fluid before installing it in the engine. New lifters already contain test fluid.

Install new (or cleaned) hydraulic lifters through push rod openings with a magnet. Install cylinder head and related parts.

COLLAPSED LIFTER SPECIFICATIONS

COLLAPSED LIFTER CLEARANCE

1. Using a feeler gauge and straightedge, check cylinder block head surface for flatness. Surface should be flat within .003" (.08 mm) over entire surface. Check cylinder bore for wear, taper, out-of-round and piston fit. See «ENGINE SPECIFICATIONS»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) tables.
2. Use only equal parts of kerosene and SAE 20 motor oil for honing cylinder bores. Install and tighten main bearing caps to specifications before cylinder refinishing. Use ONLY a spring-loaded type cylinder hone. After honing, allow cylinders to cool. Thoroughly clean bore with detergent and water solution.
3. Rinse solution in bore thoroughly with clean water. Wipe bores clean with lint free cloth. Lubricate cylinder bores with engine oil. Tap cylinder head bolt threads in cylinder block.

OIL PAN

1. Disconnect negative battery cable. Raise and support vehicle. Drain crankcase. Drain coolant by removing lower radiator hose. Remove roll restrictor (MTX only). Disconnect starter cable.
2. Remove starter. Disconnect exhaust pipe from oil pan. Remove engine coolant tube located at lower radiator hose, at water pump and at tabs on oil pan. Position air conditioner line off to side. Remove oil pan.

OIL PAN SPECIFICATIONS

PISTON & ROD ASSEMBLY

Note. The following procedures are with oil pan, oil pump and cylinder head removed. Ensure components are marked, to ensure installation to original position and location.

1. Ensure pistons and rods are installed in cylinder from which they were removed. Ensure notch on piston faces front of engine. Ensure oil hole in rod and notch on piston are in proper position. (Scheme 5) Check piston fit before assembling piston on rod. Refer to «FITTING PISTONS»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d__fitting-pistons). Check rod bearing clearance.
2. Check piston pin fit. If not within specifications, remove pin and measure pin bore in piston and rod. Replace as necessary. If piston pin is to be replaced, replace piston and pin as an assembly. See «ENGINE SPECIFICATIONS»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) tables.

Piston & Rod Alignment. Scheme 5

FITTING PISTONS

1. Check piston-to-bore clearance. See «ENGINE SPECIFICATIONS»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) tables. Standard size pistons are color coded Red, Blue or Yellow on the piston dome. See «PISTON SIZE CODE»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) table.
2. If bore diameter is in lower one-third of specifications, use a Red coded piston. If bore diameter is in middle one-third of specifications, use a Blue coded piston. If bore diameter is in upper one-third of specifications, use Yellow coded piston. The Yellow coded piston is .004" (.10 mm) oversize. Use proper size piston to acquire specified clearance.

PISTON SIZE CODES

FITTING RINGS

1. Select proper rings for bore diameter. Place ring square in cylinder bore, below normal ring wear area. Measure the ring end gap. If ring end gap is less than specifications, remove necessary amount from end of ring. If ring gap is greater than specifications, use a different set of rings. Ensure rings are installed in cylinder bore in which they were measured.
2. Check side clearance of rings after installing on piston. Ensure clearance is within specifications around entire circumference. If lower lands of piston have high steps, replace piston. Replace piston and rings if side clearance is not within specifications. Properly set ring ends on piston before installing into cylinder. (Scheme 6) See «ENGINE SPECIFICATIONS»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) tables.

Piston Ring End Gap Spacing. Scheme 6

CRANKSHAFT & ROD BEARINGS

Note. Following procedures are with oil pan and oil pump removed.

CONNECTING ROD BEARINGS

1. Use Plastigage method to check clearance of main and rod bearings. See «ENGINE SPECIFICATIONS»(/ford/taurus/i-1985-1991/remont/mechanical/#25l-4-cyl-vin-d) tables. If replacing standard size bearings, use new bearings which fit with the minimum specified clearance.
2. If desired clearance cannot be obtained with standard bearing, try a standard bearing in combination with an undersize bearing. Standard bearings may be used with a .001" (.025 mm) or .002" (.050 mm) undersize bearing. Tighten all bolt/nuts to specifications.

Install dial indicator on front of engine with pointer on end of crankshaft. Pry crankshaft fully rear and zero indicator. Pry crankshaft fully forward and note reading. If end play exceeds specifications, replace thrust bearing. If end play is less than specifications, remove thrust bearing and inspect surfaces. Replace as necessary. See ENGINE SPECIFICATIONS tables.

1. Remove transaxle. On manual transaxle models, remove clutch disc, pressure plate and flywheel. See appropriate CLUTCHES article. On automatic transaxle models, remove flexplate. See appropriate TRANSMISSION SERVICING article.
2. Use an awl and punch a hole into the metal surface of the seal. Use care not to damage sealing surfaces. Install Jet Plug Remover (T77L-9533-B) and remove oil seal.

Check crankshaft seal surface for wear and replace as necessary. Coat crankshaft seal area and lip of oil seal with engine oil. Using Rear Crankshaft Seal Replacer (T81P-6701-A), install oil seal. Tighten bolts on seal replacer evenly, to ensure seal is installed squarely. To complete installation, reverse removal procedure.

FRONT CRANKSHAFT OIL SEAL

Remove accessory belts. Remove bolt and washer from crankshaft damper. Remove crankshaft damper with Differential Side Bearing Puller (T77F-4220-B1). Use Seal Remover (T74P-6700-A) and remove front oil seal. Coat new seal with Long-Life Lubricant C1AZ-19859-B). Use Pinion Oil Seal Installer (T83T-4676-A) and install new oil seal. To complete installation, reverse removal procedure.

ENGINE OILING SYSTEM

Engine oiling is a full pressure system. Oil pump is bolted to bottom of engine block inside oil pan. An intermediate shaft attached to distributor drives the oil pump.

Crankcase Capacity

Crankcase capacity for the 2.3L engine is 4.5 qts. (4.3L) with filter change. The 2.5L engine is 5 qts. (4.7L) with filter change. DO NOT change oil without changing filter.

Normal Oil Pressure (Hot)

Normal oil pressure is 55-70 psi (3.9-4.9 kg/cm 2 ) at 2000 RPM.

Removal & Installation

Remove oil pan. Remove oil pump and pick-up tube attaching bolts. Remove oil pump assembly. Remove pick-up tube from oil pump. To install, reverse removal procedure. Install new gaskets. Fill oil pump inlet port with engine oil. Rotate oil pump shaft until oil flows from outlet.

Remove cover. Clean all components in solvent and dry with compressed air. Check inside of housing, outer race and rotor for wear and damage. Replace pump assembly if necessary. Measure inner rotor tip clearance. Measure rotor end play. Check relief valve spring and replace pump assembly as necessary. See OIL PUMP SPECIFICATIONS table.

OIL PUMP SPECIFICATIONS

WATER PUMP

Disconnect negative battery cable and drain cooling system. Remove thermactor pump and bracket assembly. Remove accessory belts. Remove water pump inlet tube. Remove water pump retaining bolts. Remove water pump and gasket. Clean gasket mating surfaces. Coat new water pump gasket with Perfect Seal Sealing Compound (B5A-19554-A) and position on engine block. To complete installation, reverse removal procedure.

Note. For further information on cooling system capacities and other cooling system components, see ENGINE COOLING SYSTEMS article.

2.5L Engine Serpentine Belt Routing. Scheme 7

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

GENERAL ENGINE SPECIFICATIONS

VALVE SPECIFICATIONS

VALVE SPECIFICATIONS

PISTON/PIN/RING SPECIFICATIONS

PISTONS, PINS & RINGS SPECIFICATIONS

BEARING SPECIFICATIONS

CRANKSHAFT MAIN & CONNECTING ROD BEARINGS

VALVE SPRING SPECIFICATIONS

VALVE SPRINGS SPECIFICATIONS

CAMSHAFT SPECIFICATIONS

CAMSHAFT SPECIFICATIONS

See also:
• ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION
• TIMING CHAIN SPECIFICATIONS
• CAMSHAFT FRONT COVER & TIMING CHAIN REMOVAL & INSTALLATION
• CAMSHAFT END PLAY
• CAMSHAFT LOBE LIFT
• FITTING PISTONS