Oil Pump

NOTE: Oil pump is mounted on front engine housing and must be checked or overhauled with front engine cover removed.

Fig 1: Measuring Oil Pump Drive Chain Slack

Courtesy of MAZDA MOTORS CORP.

With front engine cover removed, check oil pump drive chain slack by pressing finger against chain and measuring slack. If measurement exceeds 0.47" (12 mm), replace drive chain. See Fig 1.
With oil pump removed, disassemble in following order: Remove snap ring, rear outer rotor, rear inner rotor, key and middle plate; remove front inner rotor, key, shaft, spring pin and front outer rotor.

Fig 2: Exploded View of Oil Pump Assembly
Courtesy of MAZDA MOTORS CORP.
Insert a feeler gauge between lobes of inner and outer rotors and check clearance. If beyond 0.006" (0.15 mm), replace both rotors.
Check clearance between outer rotor and pump housing with a feeler gauge. If clearance exceeds 0.012" (0.30 mm), replace rotors or housing.
Place a straightedge across pump mounting surface and check rotor end play with a feeler gauge. If beyond 0.006" (0.15 mm), replace pump body or rotors.
To assemble oil pump, reverse disassembly procedure. Install oil pump and tighten bolts. Install sprockets and chain as previously outlined. See ECCENTRIC SHAFT ENDTHRUST ADJUSTMENT .