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So in the next 2 or 3 months I will be in the market for my first G8 GT. Im sure this has been addressed somewhere else but Ive been doing some searching around and havent really found much on things to look out for when purchasing a used G8 GT. My question is what should I search for (Mainily drivetrain) when I begin my search for the right G8. Do the trannys/rear end have issues? Motor wise is there any common issues on these cars?

Ive owned plenty of GMs but this will my first automatic car (My duramax is the only automatic GM ive owned)
so I just want to make sure Im looking for the right things when i purchase my G8. I am aware that when purchasing a used vehicle, especially with higher mileage, there will always be issues but what are the main common issues these cars have?

Thanks in advance
 

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Really, the only thing that really sux on a G8 GT is the dod 6.0l engine. The dod valves are of a poor design and prone to fail. That being said, failure is not a guarantee. There are many with over 200k on the clock on stock valve trains. It kinda depends on how its treated and how often the oil was/is changed. The 6L80e transmission is pretty solid along with the rear end.
 

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Try and locate a GXP. Has the more bullet proof 6.2L engine.
A rarer G8 model with a price tag to match. Also can be had with a manual trans for those who like three pedals.
Good hunting.
 

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Open the hood. Just because the emblem on the back says G8, that doesn't mean it has a V8 under the hood. Won't be making that mistake again.
 

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I think the only other main issue some of these cars had was the front control arm issue. It would clunk or squeak when hitting bumps. I'm sure most of the bad ones have been replaced by now though.
 

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Discussion Starter #9
I think the only other main issue some of these cars had was the front control arm issue. It would clunk or squeak when hitting bumps. I'm sure most of the bad ones have been replaced by now though.
Thats not to big an issue. I have a lift so i could always just the buhings or the control arm it self. Seems like besides the DOD these cars are pretty solid.

This might seem like a stupid question but does the car need to be tuned after doing a DOD delete? I would suppose so but never done one.
 

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Well, the emblem SAYS G8, and it's a muscular looking car. You would ASSUME it has a V8 engine, wouldn't you?
Not really. Pontiac is the make. G8 is the model. GXP, GT, or base is the trim level. Would never purchase a vehicle before looking under the hood nor take the seller at their "word" unless it's one he(double hockey sticks) of a deal or a restoration project.
 

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I would think that you will have to retune it if you did a dod delete
 

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Definitely some questionable responses in this thread....Anyway, strut bushings of the rubber variety get eaten by this hefty pig. When you pop the hood, look at the strut caps and see if they are popped up more than half an inch off the strut tower. Preferably, they should be sitting right on the strut tower. Easy part to change and lots of replacement options. Someone mentioned the control arms in the front, there are 4 and the bushing is not usually the part that fails, it's the ball joint. Go over some rough pavement during the test drive and listen for clanking/rattling (but can also be endinks). Watch the engine while it's running and check the crank pulley for wobble and listen for lifter tick/squeaking that speeds up with throttle. That is the main failure point of the DOD, not any kind of valves as previously stated. Once you get a cam in there, replace all 16 lifters, don't skimp on parts and yes you will absolutely need a tune once the cam is changed out or if you're staying stock and want to turn off the DOD(turning it off does not change anything mechanically and it is still the weak link). Also, during the test drive, take off from a dead stop with some authority. Listen for a clunking coming from under your seat. Could be the driveshaft center support bearing (2 piece shaft). A general "floatiness" will also be felt if the cars shocks and struts are on their way out. Other than those issues, mechanically there's not much else to really worry about.
 

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Stock V6 exhaust has a single pipe on each side. V8’s have dual tips on each side. If it’s modded, yer on yer own.
 

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Discussion Starter #16
Definitely some questionable responses in this thread....Anyway, strut bushings of the rubber variety get eaten by this hefty pig. When you pop the hood, look at the strut caps and see if they are popped up more than half an inch off the strut tower. Preferably, they should be sitting right on the strut tower. Easy part to change and lots of replacement options. Someone mentioned the control arms in the front, there are 4 and the bushing is not usually the part that fails, it's the ball joint. Go over some rough pavement during the test drive and listen for clanking/rattling (but can also be endinks). Watch the engine while it's running and check the crank pulley for wobble and listen for lifter tick/squeaking that speeds up with throttle. That is the main failure point of the DOD, not any kind of valves as previously stated. Once you get a cam in there, replace all 16 lifters, don't skimp on parts and yes you will absolutely need a tune once the cam is changed out or if you're staying stock and want to turn off the DOD(turning it off does not change anything mechanically and it is still the weak link). Also, during the test drive, take off from a dead stop with some authority. Listen for a clunking coming from under your seat. Could be the driveshaft center support bearing (2 piece shaft). A general "floatiness" will also be felt if the cars shocks and struts are on their way out. Other than those issues, mechanically there's not much else to really worry about.
Thank you this is the type of response I was hoping to receive. I plan to keep the engine internals fairly stock. My first order of business is to address the DOD issue and since im in there replace all the lifters not just DOD and since im going to have to tune it afterwards figure I do headers, intake and crank pulley. Ill go ahead check and change all the bushings and ball joints if need be.

Thanks
 

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I understand your wanting to be pro-active and addressing the DOD issue but keep in mind there are a far greater percentage of 6.0L's out there that have not and will never have lifter problems.
Your call, your G8 but something to think about.
 

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in addition to the dod (hasn't been a problem for me *knocks on wood*) check to see if the LCA recall has been done and just know the paint f'n sucks on this car. Like the worst, most rock chip paint ever known to the car world.

Most everything else is minor.
 

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I understand your wanting to be pro-active and addressing the DOD issue but keep in mind there are a far greater percentage of 6.0L's out there that have not and will never have lifter problems.
Your call, your G8 but something to think about.
This i agree with. Treat her well, change and check the oil and listen for the early warning signs.
 
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