1999 Pontiac Montana Knocking noise that disappears

1999 PONTIAC MONTANA
181,000 MILES • 6 CYL • FWD • AUTOMATIC
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JOSH13205
  • MEMBER
  • 2 POSTS
I have just bought the van and was told it has a knock. It had a brand new Jasper motor put in it 60000 miles ago. It is out of the Jasper warranty. It had set for about 4 months. It only knocks for about 30 seconds and then disappears. It sounds like it is from the top of the motor. Could it be the lifters or rockers? Or perhaps something with the spark?
Mar 20, 2010 at 2:28 PM
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JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
The rockers will make more of a ticking noise. It may be cam bearings. Unlike water, steel expands when it gets hot. Thus, if there is excessive play in a bearing, it sometimes will go away as the engine gets hot.
Apr 25, 2010 at 12:44 AM
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