1997 Chevy Monte Carlo Compression is eratic

1997 CHEVROLET MONTE CARLO
123,000 MILES • 6 CYL • FWD • AUTOMATIC
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CROLHEISER
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  • 3 POSTS
This is the 24 valve DOHC 3.4L engine. I did compression check after I installed the new timing belt (replaced the broken belt). I got the following readings: #1 = 170; #2 = 40; #3 = 0; #4 = 180; #5 = 30; #6 = 65. I then took the heads off as I thought valves were bent. Took the heads to engine shop & they said vacumm tested OK, so the heads are good.
Can you tell me why the compression could be out like that when the heads are good?
Thanks,
Feb 4, 2008 at 6:19 PM
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BLACKOP555
  • ✓ASE Certified Mechanic
  • 10,386 POSTS
  • ASE Certified Mechanic
the piston rings could be bad or chances are the cam shaft is worn out and not proplerly functioning. make sure the pushrods arnt bent.
Feb 4, 2008 at 7:20 PM
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