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Discussion Starter #1
I took my G8 GT into a shop and asked them to perform an engine and tranny test. The engine results are here for a 122k mileage motor.. They did a compression and head leak test.

Results of the tests are below….

Cylinder compression leakdown
#1 – 148 - 4%
#2 - 145 – 4%
#3 – 145 – 4%
#4 – 137 – 7%
#5 – 148 – 4%
#6 – 143 – 5%
#7 – 147 – 5%
#8 – 145 – 6%

What do you guys think? Healthy? Shop said it looked good.

Tranny checked out okay.

I get a little bump/slip when I accelerate hard from a stop. They believe this is the rear bearings so have suggested a rear end rebuild.

Comments anyone?
 

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There is no slip in bearings. If you are talking about wheel hop it has nothing to do with bearing. Wheel hop is caused by axle twist and soft rubber bushing deflection in the suspension arms and subframe. If the axle or carrier bearings were failing the noise would be constant under load.
 

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Cylinder compression leakdown
#1 – 148 - 4%
#2 - 145 – 4%
#3 – 145 – 4%
#4 – 137 – 7%
#5 – 148 – 4%
#6 – 143 – 5%
#7 – 147 – 5%
#8 – 145 – 6%

Sure would like an explanation of those numbers.
First I thought was percentage based on 150 psi .
But looking at the numbers, they don't stack up.
Lowest number, biggest, percentage ok
Highest number, smallest percentage,
Makes sense, but then there are lower numbers with lower percentages?
 

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I'd guess the percentage is the amount it drops over x time. Looks solid, not great but I'd say normal for 140k mile worn rings. If one or the other was significantly lower then you would suspect a sealing issue, rings, valve seats, head gasket, etc.
 

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What does a rear end rebuild entail?
 

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Discussion Starter #6 (Edited)
Maybe I called the rear work the wrong thing. No tech/mechanic here so..

The shop ordered a Bearing Kit for me. I paid for the kit in advance as he said it was on back order and not available until the mid-end of May.

Here is what is on the invoice..

Bearing Kit includes Timken Tapered Bearings ( Carrier, Front and Rear Pinion, Pilot where applicable), Brush, Cover Gasket (or RTV), Crush Sleeve (or Preload Shim Pack), Marking Compound, Pinion Nut, Pinion Seal, Ring Gear Bolts, Shims (Pinion, Carrier) - $395 US

For the numbers above, the first is the compression, the second is the leakdown for the cylinders. I think.
 

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The bearing kit is to rebuild the rear end i.e. rear differential. At 122,000 miles would merely swap it with one known to be in good condition and call it a day.
 

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And your compression/leakdown numbers are fine. Don't listen to anybody who suggests you have a problem requiring attention there.
 

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I took my G8 GT into a shop and asked them to perform an engine and tranny test. The engine results are here for a 122k mileage motor.. They did a compression and head leak test.

Results of the tests are below….

Cylinder compression leakdown
#1 – 148 - 4%
#2 - 145 – 4%
#3 – 145 – 4%
#4 – 137 – 7%
#5 – 148 – 4%
#6 – 143 – 5%
#7 – 147 – 5%
#8 – 145 – 6%

What do you guys think? Healthy? Shop said it looked good.

Tranny checked out okay.

I get a little bump/slip when I accelerate hard from a stop. They believe this is the rear bearings so have suggested a rear end rebuild.

Comments anyone?
I took my G8 GT into a shop and asked them to perform an engine and tranny test. The engine results are here for a 122k mileage motor.. They did a compression and head leak test.

Results of the tests are below….

Cylinder compression leakdown
#1 – 148 - 4%
#2 - 145 – 4%
#3 – 145 – 4%
#4 – 137 – 7%
#5 – 148 – 4%
#6 – 143 – 5%
#7 – 147 – 5%
#8 – 145 – 6%

What do you guys think? Healthy? Shop said it looked good.

Tranny checked out okay.

I get a little bump/slip when I accelerate hard from a stop. They believe this is the rear bearings so have suggested a rear end rebuild.

Comments anyone?
That is great for for a 122k miles.. sounds like you've taken good care of that motor.
 

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That is great for for a 122k miles.. sounds like you've taken good care of that motor.
I bought a 2009 GT two months ago but, I haven't been able to drive it hardly. DMV has been scheduling visits and I finally get in there tomorrow to get title and tags...
:unsure:
 

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Discussion Starter #12
True. I bought it mid January. However, it will continue to get TLC going forward.

It lived in the southern US. Georgia to Louisiana.
 
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