2.5L V6: Diagnosis Mazda MX-6 I

Inspection

1. Inspect cylinder head for cracks or 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.
2. Measure cylinder head bolt length. (Scheme 2) Replace cylinder head bolts if distance is not 5.26-5.29" (133.7-134.3 mm).
3. Ensure cylinder head bolt holes are completely clean. Inspect cylinder block deck surface for warpage. Replace cylinder block if warpage exceeds specification. See «CYLINDER BLOCK»(ref-49161-S19322651942001011500000) under ENGINE SPECIFICATIONS. Inspect camshaft and components. See «CAMSHAFT»(ref-49161-S03740297402001011500000) under REMOVAL & INSTALLATION.

Scheme 2

Scheme 3

1. Install new "O" ring on oil control plug. Coat new "O" rings with engine oil. Install cylinder head gasket on cylinder block, paying attention to identification marks on head gaskets. (Scheme 3)
2. Ensure oil control plug "O" rings are coated with engine oil. Install cylinder head. Apply engine oil on cylinder head bolt threads and cylinder head bolt-to-cylinder head contact surfaces.
3. Install cylinder head bolts with washers and tighten to specification in sequence. (Scheme 2), and also see the «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000). After tightening head bolts to torque specification, put a paint mark on each head bolt. Using paint mark as a reference, further tighten head bolts 85-95 degrees in sequence. (Scheme 2)
4. Install camshafts using proper installation procedure. See «CAMSHAFT»(ref-49161-S03740297402001011500000) under REMOVAL & INSTALLATION. To install remaining components, reverse removal procedure.
5. Before installing valve cover and gasket, apply sealant at specified areas on cylinder head. (Scheme 4) Apply sealant on NEW valve cover gasket, and install gasket in valve cover. Install valve cover and gasket.
6. Install and tighten valve cover bolts to specification in sequence using several steps. (Scheme 5), and also see the «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000).
7. Coat distributor "O" ring and drive blade on distributor with engine oil. When installing distributor, rotate crankshaft so No. 1 cylinder is at TDC on compression stroke.
8. Ensure timing mark on crankshaft pulley aligns with TDC mark on timing belt cover. Align distributor drive blade with groove on distributor body.
9. Install distributor and hold-down bolt. Install remaining components. Tighten all fasteners to specification. See the «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000). Fill and bleed cooling system. See «COOLING SYSTEM BLEEDING»(ref-49161-S36555986632001011500000) under REMOVAL & INSTALLATION. Adjust ignition timing.

Scheme 4

Scheme 5

1. Inspect timing belt for damaged teeth, cracking and oil contamination. Ensure idler pulleys No. 1 and 2 and tensioner pulley rotate freely. Replace damaged components.
2. Inspect timing belt tensioner for signs of oil leakage. Replace timing belt tensioner if oil leakage exists. Measure timing belt tensioner rod protrusion from end of rod to edge of the housing. (Scheme 6) Replace timing belt tensioner if distance is not.550-.630" (13.97-16.00 mm).

Scheme 6

Scheme 7

1. If crankshaft sprocket was removed, align crankshaft sprocket with key in crankshaft. Install crankshaft sprocket on crankshaft with flange toward cylinder block. see scheme 9
2. If camshaft sprocket was removed, align dowel pin in camshaft with hole in camshaft sprocket. Install camshaft sprocket. Coat retaining bolt threads with oil. Install bolt and tighten to specification. See «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000). CAUTION: Ensure camshaft sprocket is installed with identification mark facing outward. Right camshaft sprocket has an "R" identification mark and left camshaft sprocket has an "L" identification mark. see scheme 10
3. Place timing belt tensioner in a press using a flat washer to prevent damage to timing belt tensioner. (Scheme 7) Compress tensioner rod until holes in rod and housing are aligned and install.06" (1.5 mm) diameter pin through holes in housing and rod to hold rod in retracted position. (Scheme 7)
4. Install timing belt tensioner on cylinder block with the upper retaining bolt only, do not fully tighten upper bolt. Install No. 2 idler pulley and tighten to specification. See the «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000). CAUTION: If reusing timing belt, ensure timing belt is installed in original direction of rotation.
5. Ensure all timing marks align. see scheme 10 Install timing belt on sprockets and ensure all slack is on tensioner side. Ensure timing belt fully engages all sprockets.
6. Push outward at bottom of timing belt tensioner and install lower retaining bolt in timing belt tensioner. Tighten both timing belt tensioner retaining bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000).
7. Remove pin from timing belt tensioner, allowing tension to be applied on timing belt. Rotate crankshaft 2 full revolutions clockwise from TDC to TDC. Ensure timing marks on camshaft sprockets and crankshaft sprocket are properly aligned. see scheme 10 If timing marks are not aligned, remove and repeat entire timing belt installation procedure.
8. Timing belt deflection must be checked. Apply 22 lbs. (10 kg) of force at designated area on timing belt and check timing belt deflection. (Scheme 8) Timing belt deflection should be.24-.31" (6.0-8.0 mm). If timing belt deflection is not within specification, replace timing belt tensioner.
9. Install timing belt covers using NEW gaskets. Tighten retaining bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000). Install dipstick tube with new "O" ring. To install remaining components, reverse removal procedure. Tighten fasteners to specification. See «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000).

Scheme 8

1. Inspect components for damage. Measure HLA diameter and bore diameter, and determine oil clearance. Ensure oil clearance is within specification. Replace components if oil clearance is not within specification. See «HYDRAULIC LASH ADJUSTERS»(ref-49161-S24563303612001011500000) under ENGINE SPECIFICATIONS.
2. Hold HLA upright and attempt to compress adjuster using hand pressure only. If plunger moves, replace HLA.

Inspect components for damage. Check camshaft journal diameter, lobe height and runout. Replace camshaft if any measurement is not within specs. See CAMSHAFT under ENGINE SPECIFICATIONS.

Scheme 9

Scheme 10

Scheme 11

1. If installing friction gear, install friction gear on camshaft. Ensure reference mark on friction gear is aligned with reference mark on camshaft gear. Install retaining nut, and tighten it to specification. See «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000).
2. Coat valve lash adjuster, camshaft journals and cylinder head surfaces with engine oil. Install HLAs in original location (if removed). Install camshafts in cylinder head with timing marks aligned. (Scheme 9)
3. Ensure camshaft bearing cap surfaces are clean on cylinder head. Apply sealant at designated areas on cylinder head. (Scheme 10) CAUTION: DO NOT allow sealant to contact camshaft. NOTE: Camshaft bearing caps on right cylinder head are identified by numbers, with No. 1 at timing belt end of engine. Camshaft bearing caps on left cylinder head are identified by letters, with "A" at timing belt end of engine.
4. Install thrust bearing caps (with bolts) loosely. (Scheme 11) Install remaining camshaft bearing caps (with bolts) loosely.
5. Tighten camshaft bearing cap bolts to specification in sequence using several steps. (Scheme 11) See the «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000). DO NOT let camshafts bind.
6. Lubricate new camshaft oil seal. Using hammer and suitable diameter pipe, tap camshaft oil seal into cylinder head. Apply sealant on NEW blind cap. Using soft-faced hammer, tap blind cap into cylinder head.
7. Install coolant outlet. Tighten retaining bolts to specification. Install seal plate. Tighten retaining bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000).
8. Hold camshaft from turning by using a wrench on camshaft hex. Install left and right camshaft pulleys as identified by "L" and "R" stamped on them. Tighten camshaft pulley bolts to specification. See «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000).
9. Apply sealant at specified areas on cylinder head. (Scheme 4) Apply sealant on new valve cover gasket and install in valve cover. Install valve cover and gasket.
10. Install and tighten valve cover bolts to specification in sequence using several steps. (Scheme 5), and also see the «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000). Rotate crankshaft so No. 1 cylinder is at TDC on compression stroke. Ensure timing mark on crankshaft pulley aligns with TDC mark on timing belt cover. Coat distributor "O" ring and drive blade on distributor with engine oil. Align groove on distributor body drive blade.
11. Install distributor and hold-down bolt. To install remaining components, reverse removal procedure. Tighten all fasteners to specification. See «TORQUE SPECIFICATIONS»(ref-49161-S23175338032001011500000). Fill and bleed cooling system. See «COOLING SYSTEM BLEEDING»(ref-49161-S36555986632001011500000) under REMOVAL & INSTALLATION.

1. Inspect components for damage. Ensure relief valve slides freely in bore. Install inner and outer rotors in oil pump body. Using feeler gauge, measure clearance between outer rotor and oil pump body. See «OIL PUMP SPECIFICATIONS»(ref-49161-S10254819152001011500000) .
2. Measure rotor tip clearance between tips of both rotors. Place straightedge across oil pump body, above both rotors. Measure rotor end clearance between straightedge and rotor surface. Replace rotor assembly or oil pump body if any measurement exceeds specification.
3. Measure free length of spring for relief valve. Replace spring if free length is not 1.842" (46.79 mm).

OIL PUMP SPECIFICATIONS