Pontiac G8 2008-09 & Chevrolet SS 2014+ LSX based RWD 4-door sedans

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Old 03-15-2018, 08:11 AM
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I'm currently looking to purchase a Pontiac G8 GXP. Not a hundred percent sure but do they have AFM or DOD ? Anything in particular I should look for on that car?
Thanks
Old 03-15-2018, 11:28 AM
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The GXP came only with the LS3 and was not equipped with DOD/AFM. Common issues will be the same as the GTs, minus the DOD of course.
Old 03-15-2018, 11:42 AM
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Common issues as in what ? I just started looking , so I haven't done a lot of research just yet
Old 03-15-2018, 01:47 PM
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Front strut mounts and engine mounts tend to self destruct.
Old 03-16-2018, 02:32 PM
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Struts/shocks (discontinued on the GXP).
Strut mounts.
Driver side engine mount.
Driveshaft carrier bearing.
Radiator upper end tank.
Seat bolster trim.
Garbage paint.
A6 transmission tune.
Old 03-25-2018, 05:47 PM
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I have a GXP and here are my issues.

Rear spoiler clear coat is peeling.

Rear door panel seals leaked, had to fix it twice. It's the seal behind the panel that seals the plastic to the actual door. The rubber gasket material fails so the water doesn't pass through the door but it goes on to the rear floor instead.

Headliner died probably as a result of the interior getting wet from the door leaking.

Keep getting a code for either gas cap (replaced still get code) or a sensor in the evap system failing (have sensor but have not replaced since it is on top of fuel tank).
AC stopped pumping cold air, not sure what the deal is there but I would not say this is a GXP specific issue.

I Now have low compression in #2 cylinder. I do not think this is a GXP specific type of issue, just something that failed in my LS3, might be a valve, I have not torn it down yet.

The outer windshield trim/seal has dry rotted.

I have not had the strut issue.
Performance wise it has been great up until the cylinder issue and associated codes.
It's pretty much has the mechanical bits of a 5th Gen Camaro so that stuff is easy to source. If you need interior pieces or need any kind of exterior parts, it maybe a chore to find. I know for a while finding windshield wipers was a real PIA.
Overall, I think it was a better effort by Holden than the GTO (I had a 2005) but like other GM products of that era the interior and the paint simply do not hold up very well.

I have not had any of the other mechanical issues mentioned in previous posts but I suppose I should give it time. I have thought about replacing the two piece drive shaft but I have 75k on mine and that has never been an issue, unlike the one in my dually. If you plan to race it, I would go find a one piece drive shaft for peace of mind. My car is completely stock.

If you want a 4 door hot rod with a LS engine and a manual transmission then this is your ticket.
Old 03-25-2018, 06:00 PM
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I actually just got back from picking mine up . Flew to Florida and drove back to Indiana . Everything seems great so far . I do have tpms light on , but other than that , I LOVE it ! . It did just under 23mpg on a 1100 mile trip .
Old 03-26-2018, 01:06 AM
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We are the original owners of a GT with 54k on it now. The only problem we have had with it was water in the driver's footwell - this was the result of a plug that was placed in the evaporator tube from the factory that dealers typically failed to remove. That was taken care of during the first month we owned the car, and since then, we have not had a single problem with the car.

I keep the car waxed/polished. Very few stone chips, though it sees minimal freeway time.

Every now and then we get a code from the gas cap not being tight. I think the sensor is over-sensitive.

I will mention that the leather and interior trim are high maintenance compared to an F-body. And as stated above, the factory A6 transmission tune sucks.

Last edited by RevGTO; 03-26-2018 at 01:16 AM.
Old 03-29-2018, 01:58 PM
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Strange no one mentioned front ball joints and arm bushings...or the radio/HVAC controls randomly working.
Old 03-29-2018, 02:24 PM
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Good thing I had my mind made up before I started this thread ! LOL
Old 03-29-2018, 11:26 PM
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Originally Posted by Jenson
Strange no one mentioned front ball joints and arm bushings...or the radio/HVAC controls randomly working.
Haven't had a problem with any of these, though I know that the arm bushings are especially common.
Old 03-30-2018, 06:53 AM
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Originally Posted by RevGTO
Haven't had a problem with any of these, though I know that the arm bushings are especially common.
It's the ball joints that fail, and primarily on the lower control arm. Other than being soft the bushings aren't much of a problem.
Old 03-30-2018, 07:59 PM
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Originally Posted by Jenson
Strange no one mentioned front ball joints and arm bushings...or the radio/HVAC controls randomly working.
I have never experienced any of these issues with my GXP but have with other GM vehicles.

When the AC blows it makes a lot of noise. There is a mod to reduce it but am not sure what folks do. You will have to go to a G8 specific forum for that.
Old 03-30-2018, 08:24 PM
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Originally Posted by Marc 85Z28
It's the ball joints that fail, and primarily on the lower control arm. Other than being soft the bushings aren't much of a problem.
Lower control arm bushings are the number one fail issue on G8's; so much so, that GM announced an extended replacement warranty on them a few years ago.
Old 03-31-2018, 03:36 PM
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Originally Posted by RevGTO
Lower control arm bushings are the number one fail issue on G8's; so much so, that GM announced an extended replacement warranty on them a few years ago.
No. The failure was in the ball joint.

I've been through 2 sets of arms on my car (>200K miles), and have replaced several more at work on customer's cars. I'm quite familiar with them, thanks.
Old 04-01-2018, 10:08 PM
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LCA TSB: http://www.g8board.com/forums/99-tsb...all-bumps.html

Ball Joint Campaign (see post 18):http://www.g8board.com/forums/20-g8-...ll-joints.html

Last edited by RevGTO; 04-01-2018 at 10:23 PM.
Old 04-02-2018, 06:49 AM
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Originally Posted by RevGTO
Like I said, ball joints.
Old 04-02-2018, 08:42 PM
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Originally Posted by Marc 85Z28
Like I said, ball joints.
Unquestionably a huge part of the problem. But are you saying that all LCA issues are ball joint problems? There have been many reports of LCA bushing failure as well.

Last edited by RevGTO; 04-03-2018 at 12:26 AM.
Old 04-03-2018, 10:32 AM
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Originally Posted by RevGTO
Unquestionably a huge part of the problem. But are you saying that all LCA issues are ball joint problems? There have been many reports of LCA bushing failure as well.
Not part of the problem, the ball joints are THE problem.

I have never had a front LCA bushing failure on my personal car nor any of the cars that come through my shop. None of the people that I know with G8s have ever indicated a problem.

ALL front LCA issues are due to ball joint failure from contamination.
Old 04-03-2018, 09:46 PM
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Originally Posted by Marc 85Z28
ALL front LCA issues are due to ball joint failure from contamination.
Good info - thanks for the correction. Whether there was misinformation back in the day or my memory had become confused, I had understood that contamination could also destroy the LCA bushings and that was an issue leading to the extended replacement warranty.

I would guess that one reason we haven't had any apparent issues at 55k is that our car is rarely driven in bad weather. But I should check them out, with only a year left on the replacement warranty.

That goes for the OP too.

Last edited by RevGTO; 04-03-2018 at 10:04 PM.



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