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Compression test on high mileage LS1?

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Old Sep 18, 2004 | 11:13 AM
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Default Compression test on high mileage LS1?

I have a friend who is looking at getting an older C5, probably with 75k miles or more in order to stay within his budget. What kind of PSI should he look for if he runs a compression test?
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Old Sep 18, 2004 | 11:40 AM
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Anyone.....anyone.....Bueller??
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Old Sep 18, 2004 | 12:58 PM
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I'd do a leakdown test. For that you want less than 5%.
Hope this helps.
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Old Sep 18, 2004 | 06:16 PM
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I guess it should be near 170-175. Do a leak down after compression test.
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Old Sep 18, 2004 | 07:46 PM
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You need to look for consistant #'s on all 8 cylinders, they are all close to the same!
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Old Sep 18, 2004 | 10:13 PM
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Thanks. That's about what I figured but I wanted to make sure.
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Old Sep 18, 2004 | 11:18 PM
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All cylinders should be within 10% of each other.
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Old Sep 19, 2004 | 12:58 AM
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Originally Posted by PetalBombC5
I have a friend who is looking at getting an older C5, probably with 75k miles or more in order to stay within his budget. What kind of PSI should he look for if he runs a compression test?
From the Service Manual: The minimum compression in any one cylinder should not be less than 70 percent of the highest cylinder. No cylinder should read less than 100 psi.
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