Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL KL]
21 ENGINE NOISE
DESCRIPTION
Engine noise from under hood
POSSIBLE
CAUSE
© Squeal, click or chirp noise
• Improper engine oil level
• Improper drive belt tension
© Rattle sound noise
• Loose parts
(D
Hiss sound noise
• Vacuum leaks
• Loose spark plug
• Air leaks from intake air system
© Rumble or grind noise
• Improper drive belt tensoion
© Rap or roar sound noise
• Exhaust system loose
© Other noise
• Camshaft friction gear noise
• MLA noise
STEP INSPECTION ACTION
1
Is squeal, click or chirp sound present? Yes Check following:
• Engine oil level.
• Drive belts.
No Go to next step.
2 Is rumble or grind sound present? Yes
Check drive belt.
No Go to next step.
3 Is rattle sound present? Yes Check location of rattle for loose parts.
No Go to next step.
4 Is hiss sound present? Yes Check following:
• Vacuum leaks.
• Spark plug loose.
• Intake air system leaks.
No Go to next step.
5 Is rap or roar sound present?
Yes Check exhaust system for loose parts.
No Go to next step.
6 Is knock sound present? Yes Go to flow chart 12 for "KNOCKING/PINGING”.
No
If noise comes from engine internal, check for friction gear
or MLA noise.
7 Verify test results. If okay, return to diagnostic index to service any additional symptoms.
22
VIBRATION CONCERNS (ENGINE)
DESCRIPTION Vibration from under hood or driveline
POSSIBLE
CAUSE
• Loose attaching bolts or worn parts
• Components malfunctioning such as worn parts
STEP INSPECTION ACTION
1 Check following components for loose
attaching bolts or worn parts:
• Cooling fan.
• Drive belt
and
pulleys.
• Engine mounts.
All items okay?
Yes Check following systems:
• Wheels.
• Transaxle.
• Driveline.
• Suspension.
No Readjust or retighten engine mount installation position.
Service as necessary for other parts.
2 Verify test results. If okay, return to diagnostic index to service any additional symptoms.
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