2.5L V6: Other Mazda MX-6 I

FUEL PRESSURE RELEASE

1. Start engine. Remove fuel pump relay (Green) located in fuse block on left side of engine compartment, in front of strut tower. Allow engine to idle until it stalls. Turn ignition off. Install fuel pump relay.
2. Before disconnecting any fuel line connections, cover connection with shop towel to absorb any residual gasoline that may remain in fuel line. Carefully loosen fuel line connection, allowing residual gasoline to be released.

COOLING SYSTEM BLEEDING

1. Fill radiator and coolant reservoir. Start engine and allow to idle until engine is at normal operating temperature. Accelerate engine to 2200-2800 RPM for 5 minutes. Shut engine off and allow engine to cool.
2. Repeat step 1). Remove filler cap. Verify coolant level is near filler neck. If coolant level is not near filler neck, repeat steps 1) and 2). Fill coolant reservoir to the FULL level.

ENGINE

Note. Remove engine and transaxle as an assembly.

Cylinder Head

1. Inspect cylinder head warpage at cylinder block and manifold areas. Resurface or replace cylinder head if warpage exceeds specification. See «CYLINDER HEAD»(ref-49161-S24812642692001011500000) under ENGINE SPECIFICATIONS. CAUTION: Ensure cylinder head height is within specification after resurfacing cylinder head. See «CYLINDER HEAD»(ref-49161-S24812642692001011500000) under ENGINE SPECIFICATIONS.
2. Ensure valve stem installed height is within specification. See VALVES under «CYLINDER HEAD»(ref-49161-S18013324402001011500000) .
3. Ensure cylinder head-to-valve lash adjuster oil clearance is within specification. See «HYDRAULIC LASH ADJUSTERS»(ref-49161-S24563303612001011500000) under ENGINE SPECIFICATIONS.

Camshaft

1. Inspect components for damage. Measure camshaft journal diameter, lobe height and runout. Replace camshaft if it is not within specification. See «CAMSHAFT»(ref-49161-S41359729702001011500000) under ENGINE SPECIFICATIONS.
2. With HLAs removed from cylinder head, install one camshaft in cylinder head without camshaft bearing caps. Check camshaft end play. Install Plastigage on camshaft journals and install bearing caps and tighten to specification. See «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000) .
3. Remove bearing caps and measure bearing oil clearance. Repeat procedure on remaining camshaft. Replace camshaft and/or cylinder head if end play or oil clearance is not within specification. See «CAMSHAFT»(ref-49161-S41359729702001011500000) under ENGINE SPECIFICATIONS.

Valve Springs

Ensure valve spring free length, pressure and out-of-square are within specification. See VALVES & VALVE SPRINGS under ENGINE SPECIFICATIONS.

Valve Stem Oil Seals

1. Lubricate valve stem oil seal with engine oil. Assemble Valve Stem Oil Seal Installer components (49-L012-001), (49-L012-005) and (49-L012-002).
2. Adjust valve stem oil seal installer so depth is set at specified distance for proper valve stem oil seal application. (Scheme 26) Adjust depth to.641" (16.28 mm) for intake valve stem oil seal or.543" (13.80 mm) for exhaust valve stem oil seal. NOTE: Intake and exhaust valve seals are different. Exhaust valve seal has ridges on top and intake valve seal does not. Ensure proper valve stem oil seal is used.
3. Insert valve stem oil seal into installer. Press valve stem oil seal on valve guide until fully seated. Remove valve stem oil seal installer.

Scheme 26

Scheme 27

1. Ensure valve guide inside diameter and installed height are within specification. See «CYLINDER HEAD»(ref-49161-S24812642692001011500000) under ENGINE SPECIFICATIONS. Replace valve guide if inside diameter exceeds specification or valve guide installed height is not within specification. NOTE: Measure valve guide installed height from top of valve guide to cylinder head surface.
2. To replace valve guide, using hammer and Valve Guide Remover (49-B012-005), drive valve guide toward camshaft side of cylinder head. To install, assemble Valve Guide Installer components (49-L012-004), (49-L012-003) and (49-L012-002).
3. Adjust valve guide installer so depth is set at specified distance for proper valve guide application. (Scheme 27) Adjust depth to.579-.602" (14.70-15.30 mm) for intake valve guide, or.480-.504" (12.20-12.80 mm) for exhaust valve guides.
4. Using hammer and valve guide installer, drive valve guide in from camshaft side of cylinder head until valve guide installer contacts cylinder head.
5. Ensure valve guide installed height is within specification. See «CYLINDER HEAD»(ref-49161-S24812642692001011500000) under ENGINE SPECIFICATIONS. If valve guide installed height is not within specification, readjust depth on valve guide installer and adjust valve guide installed height.

Valve Seat

Ensure valve seat angle and seat width are within specification. See CYLINDER HEAD under ENGINE SPECIFICATIONS. Valve seat replacement information is not available.

Valve Seat Correction Angles

Use 75-degree stone to lower valve seat contact area. Use 45-degree stone to raise valve seat contact area.

Valves

1. Ensure valve length, stem diameter, head diameter and valve margin are within specification. See «VALVES & VALVE SPRINGS»(ref-49161-S36093865362001011500000) under ENGINE SPECIFICATIONS.
2. To check valve installed height, ensure valve is within minimum refinish length. See «VALVES & VALVE SPRINGS»(ref-49161-S36093865362001011500000) under ENGINE SPECIFICATIONS.
3. Install valve in cylinder head. Using caliper, measure valve protrusion from top of valve stem to the spring seat on cylinder head. (Scheme 28) If valve stem protrusion is 1.634-1.654" (41.50-42.00 mm), valve and cylinder head can be used without installing washer on valve spring seat.
4. If valve stem protrusion is 1.658-1.692" (42.10-43.00 mm), install washer on valve spring seat so distance is 1.634" (41.50 mm). If valve stem protrusion exceeds 1.697" (43.10 mm) replace cylinder head.

Scheme 28

HYDRAULIC LASH ADJUSTER

Note. If HLAs are persistently noisy, check manufacturer for availability of modified HLAs.

Hydraulic Lash Adjuster (HLA)

1. Store HLAs in upright position, submerged in engine oil. Inspect friction surface of HLA for wear and replace as necessary.
2. To check HLA function, hold HLA in hand. Attempt to compress HLA plunger using finger. If plunger compresses replace HLA. Ensure HLA-to-cylinder head oil clearance is within specification. See «HYDRAULIC LASH ADJUSTER»(ref-49161-S24563303612001011500000) under ENGINE SPECIFICATIONS. Ensure HLA is installed in original location.

Fitting Pistons

1. Measure piston skirt at 90 degree angle to piston pin .650" (16.5 mm) below lowest piston ring groove. Measure cylinder bore diameter just below top of bore, at middle of cylinder bore and just above bottom of cylinder bore and Record measurements.
2. If cylinder taper and out-of-round are NOT within specification, bore cylinder to next oversize. See «CYLINDER BLOCK»(ref-49161-S19322651942001011500000) under ENGINE SPECIFICATIONS. If cylinder taper and out of round are within specification, subtract piston diameter measurement from cylinder bore measurement to determine piston-to-cylinder clearance. See «PISTONS, PINS & RINGS»(ref-49161-S09126852432001011500000) under ENGINE SPECIFICATIONS. If piston-to-cylinder clearance is excessive, replace piston or bore cylinder to next oversize.

Piston Rings

Ensure piston ring end gap and side clearance are within specs. See PISTONS, PINS & RINGS under ENGINE SPECIFICATIONS. Position piston ring gaps in proper areas, with identification mark "R" on ring toward top of piston. (Scheme 29)

Scheme 29

Rod Bearings

1. Ensure connecting rod and connecting rod cap are marked with matching cylinder number for reassembly reference. Piston must be installed so front mark ("R" or "L") is toward timing belt end of engine. see scheme 25
2. Measure connecting rod cap bolt length. measurement is taken from contact surface of bolt head to tip of bolt shank. Replace bolt if measurement exceeds 1.889" (48.00 mm). Coat connecting rod bolt threads with engine oil before tightening to specification. Ensure bearing oil clearance and connecting rod side play are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-49161-S36627178872001011500000) under ENGINE SPECIFICATIONS.

Scheme 30

Scheme 31

Scheme 32

Scheme 33

Scheme 34

1. Before removing crankshaft measure and record crankshaft end play. Note that cylinder block contains a lower cylinder block section. (Scheme 30) Loosen lower cylinder block bolts in sequence using several steps. (Scheme 31) CAUTION: Do not pry on cylinder block except where indicated. (Scheme 32) Note location and length of lower cylinder block bolts for reassembly reference. Bolts must be installed in proper location. (Scheme 34)
2. Remove lower cylinder block retaining bolts. To loosen lower cylinder block, tap on lower cylinder block while prying with a screwdriver at rear of cylinder block. (Scheme 32) Separate lower cylinder block from cylinder block.
3. Measure lower cylinder block bolt length and diameter at specified areas on retaining bolts "A", "B" and "C". (Scheme 33) Replace bolts if not within specification. See «LOWER CYLINDER BLOCK BOLT SPECIFICATIONS»(ref-49161-S32080918972001011500000). NOTE: Lower cylinder block bolts "A" have a No. 4 stamped on top of bolt head and bolts "B" are stamped with an "I". Bolts "C" are the shortest bolts. Bolts "D" are outer bolts. LOWER CYLINDER BLOCK BOLT SPECIFICATIONS Application In. (mm) Bolt "A" Diameter.317-.321 (8.05-8.15) Length Standard 5.34-5.37 (135.7-136.3) Maximum 5.45 (138.5) Bolt "B" Diameter.293-.297 (7.45-7.55) Length Standard 5.34-5.37 (135.7-136.3) Maximum 5.45 (138.5) Bolt "C" Length Standard 4.71-4.74 (119.7-120.3) Maximum 4.76 (121.0)
4. Ensure crankshaft journal diameter, taper and out-of-round are with within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-49161-S36627178872001011500000) under ENGINE SPECIFICATIONS. CAUTION: DO NOT remove fillet roll on crankshaft journals when grinding journals for undersize bearings.
5. Crankshaft journals can be ground for.010" (.25 mm) undersize bearings if diameter is not within specification. Grind crankshaft rod journals to 2.07454-2.0749" (52.690-52.705 mm). Grind main bearing journals to 2.4287-2.4293" (61.688-61.705 mm) for undersize bearings.
6. To check oil clearance, install upper main and thrust bearings in cylinder block. Rear (No. 4) main bearing is wider than all other main bearings. Install lower main and thrust bearings, and lower cylinder block.
7. Coat lower cylinder block bolt threads and bolt-to-lower cylinder block surface with engine oil. Install bolts "A", "B" and "C" in proper location on cylinder block. (Scheme 34) NOTE: Manufacturer does not require lower cylinder block bolts "D" to be installed when checking oil clearance.
8. Tighten bolts to specification in sequence using several steps. Perform STEPS 1 and 2 of illustration. (Scheme 34) Measure inside diameter of main bearings on front and rear main bearings. Subtract crankshaft main journal diameter from main bearing inside diameter to determine oil clearance.
9. Ensure crankshaft main bearing oil clearance is within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-49161-S36627178872001011500000) under ENGINE SPECIFICATIONS.
10. Crankshaft main journals can be ground for.010" (.25 mm) undersize bearings if oil clearance is not within specification. Grind main bearing journals to 2.4287-2.4293" (61.688-61.705 mm) for undersize bearings. CAUTION: DO NOT remove fillet roll on crankshaft journals when grinding journals for undersize bearings.
11. When performing final installation of crankshaft, ensure oil jet is installed in cylinder block. See «OIL JET»(ref-49161-S03404207362001011500000) under ENGINE OILING. Install main and thrust bearings in cylinder block and in lower cylinder block. Rear (No. 4) main bearing is wider than all other main bearings. CAUTION: Ensure thrust bearing is installed on rear (No. 4) main bearing with oil groove facing inward.
12. Coat all bearings and crankshaft journals with engine oil. Install crankshaft. Ensure lower cylinder block and cylinder block sealing surfaces are clean. Apply sealant on cylinder block in specified areas. (Scheme 35) DO NOT allow sealant to enter bolt holes.
13. Install lower cylinder block. Coat lower cylinder block bolt threads with engine oil. Install bolts in proper location on cylinder block.
14. Tighten bolts to specification in sequence using several steps. (Scheme 34) Ensure crankshaft end play is within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-49161-S36627178872001011500000) under ENGINE SPECIFICATIONS. Replace thrust bearing if end play is not within specification.

Scheme 35

Thrust Bearing

1. Install thrust bearing on rear (No. 4) main bearing with grooves facing toward crankshaft (away from cylinder block). Replace thrust bearing if crankshaft end play is not within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-49161-S36627178872001011500000) under ENGINE SPECIFICATIONS.
2. Standard thrust bearing width is .0788-.0807" (2.000-2.050 mm). Oversize thrust bearings are available in 2 different sizes. See OVERSIZE THRUST BEARING SPECIFICATIONS table.

OVERSIZE THRUST BEARING SPECIFICATIONS

Cylinder Block

1. Inspect cylinder block deck surface warpage. Replace cylinder block if deck warpage exceeds specification. See «CYLINDER BLOCK»(ref-49161-S19322651942001011500000) under ENGINE SPECIFICATIONS.
2. Measure cylinder bore diameter just below top of bore, at middle of cylinder bore and just above bottom of cylinder bore. Ensure cylinder bore diameter, taper and out-of-round are within specification.
3. If cylinder bore diameter, taper or out-of-round exceeds specification, bore cylinder to nearest oversize.

Oil Pressure

With engine at normal operating temperature, oil pressure should be 28 psi (2.0 kg/cm 2 ) at 1000 RPM and 48-71 psi (3.4-5.0 kg/cm 2 ) at 3000 RPM.

Scheme 36

CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECS

CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS SPECS