2007 Grand prix gxp 5.3 liter, "bad engine". What should I be expecting?

A coworker told me his friend has a 2007 Pontiac grand prix gxp with a 5.3 liter that he says needs an engine. No other details yet as to whats actually wrong, whether its a knock, overheating, etc. Its supposedly really clean and has 122,000 miles. I'm told I can buy it for a few hundred or its going to the junkyard. Is there a common engine failure on these? Its seems strange to me that an LS motor blow at 120k. Would this be a cylinder deactivation engine, and if so what was the common fault on those? I know I've heard it discussed here a few times but I can't remember. Any help would be appreciated as I will probably have to act fast before it heads to the junkyard.

If it's clean I would buy it and just replace the engine, might be something simple like a broken flex plate or major like a locked up engine due to lack of oil?

Enough neglect will kill anything, so it could be properly blown up.

We see the odd ls with bad roller and lobe on the cam. Plus the cylinder deactivation either broken, or causing oil burning.

Never assume the bad motor diagnosis from someone else is correct, unless they hand you a piece of connecting rod.

Just last year one of neighbors was told she had seized engine on a Buick, when she really had a starter failure.

I assume you know that this came with the aluminum block LS motor

In reply to HappyAndy:

I know thats the truth, but this diagnosis did come from a reputable local shop. I was going to talk to the shop owner and try to get a more detailed story on the failure.

Always assume bad motor when paying for a non runner, never assume when diagnosing

That said, it has the AFM/DOD 5.3 which have trouble with the cylinder deactivation system and do send metal into the oil. It has bitten several of us on the forum. If it does need an engine, you can grab one for under a grand and delete the AFM system in the computer

I don't know where anna ohio is but i'd be willing to buy it at $350 or under, if they give it to you for pull a part price(around 180 right now) and you want to make a few bucks

I believe these FWD 5.3s have a different block than all other 5.3s, so it's important to consider that they're not as common to find if you'd need a replacement.

STM317 wrote: I believe these FWD 5.3s have a different block than all other 5.3s, so it's important to consider that they're not as common to find if you'd need a replacement.

this is true.

In reply to patgizz:

Yeah, I should have added to my earlier comments to always pay for a non runner as if it really is a bad engine.

When it turns out not to be that, you win the game.

Have you bought it yet?

Its funny, when the guy first told me about the car he didnt know which engine it had. I assumed a NA 3800 because it was the most common. I was thinking about replacing the engine and keeping it for a DD because my current daily gets about 12 mpg. When he told me today that its a v8 car it eliminated the gas saver option. So its makes less sense to own but it became more intriguing. Funny how that works.

Can the engine come out of the top or does it have to go out the bottom?

If it has the metal in oil that Patgizz describes i assume full engine replacement or a professional rebuild is the only option, no fixing what is there. Is that correct?

Ive experienced that you could get away with bearings, crank turning, and cam/lifter set and cleaning the heads, but most people don't shut them down immediately when they hear something. I shut ours down the day i heard the knock and it still ate one rod bearing hard enough to need crank work

If you get it for junkyard price the heads are worth more than you'll pay for the whole car as it has the ls2 243/799 heads.

I've done w bodies out the top and from the bottom. Never done an ls4 though but I'd assume due to getting flywheel clear of bellhousing with low clearance from balancer to rh frame rail it's coming out the bottom as an assembly

Also ed morad up here in cleveland is a w body dismantler and usually has a good ls4. You can delete AFM in hptuners easily, if you're close i can do that for the cost of the tuning credits.

In reply to gearheadmb:

It is much easier to drop the engine out the bottom. I've had to do it both ways.

Pull the subframe after supporting the engine then drop the engine and trans out while lifting the car just enough up and over the lump sitting there.

Car-Parts.com shows that Morad in Cleveland has an engine but it is $1,000 with 125k miles on it. Not really close by since Anna, OH is off I-75, south of Lima but north of Dayton.

The guy wants $600. The googles make it sound like the trannys are hand grenades in these things. I dont like the prospect of buying it, having another $1000 in an engine, and then finding out i need a trans as well. Ive got myself about 65% talked out of it.

Yeah $600 is too much. Either same as the junkyard will pay or pass.

gearheadmb wrote: The guy wants $600. The googles make it sound like the trannys are hand grenades in these things. I dont like the prospect of buying it, having another $1000 in an engine, and then finding out i need a trans as well. Ive got myself about 65% talked out of it.

Yeah, transmissions were pretty spindly. And if the trans goes, the engine is even that great to have as swap fodder because the LS4 has an oddball bellhousing and some other unique features that prevents it from being easily swapped.

gearheadmb wrote: The guy wants $600. The googles make it sound like the trannys are hand grenades in these things. I dont like the prospect of buying it, having another $1000 in an engine, and then finding out i need a trans as well. Ive got myself about 65% talked out of it.

So $600 for car, $1k for engine, another $1k for trans maybe, and you're truckin'. I fail to see how this is a problem?

Searching manuals indicates that the drivetrain comes out the bottom. I could probably get it out the top if I were determined, remove damper/accessories in chassis and unbolt the trans and shift it over as far to the driver's side as possible. Maybe.

If "we" listened to the internet, we would be walking everywhere barefoot, maybe.

In reply to Knurled:

Its a problem because i dont want to spend $2600 on a car i absolutely dont need and only sort of want. i fully admit 303 hp and flappy paddles should make a grand prix more fun than it has any right to be. But it doesnt fill any needs i currently have. I already have a v8 fun car. I already have a daily that gets crappy mileage. I cant see laying out $2500-3000 and doing the job in my garage, without a hoist, when i dont even have any more inside parking.

Now, if there was one of these for the same money that was wrecked, but i knew the powertrain was good, and i had a fiero sitting around, well that would be a horse of a different color.

Spend the time and money with a new motor, install, flip for 3k with 1-1500$ in profit?

For what it's worth, when I mentioned it to some people I know, they instantly went "How the body?"

If the subframe's falling out and the rocker panels are air covered up by plastic cladding, forget it. If it's solid, then repaired that is an $8-10k car...

Heck, I either have to fix or replace my Volvo by March 2018 (won't pass emissions), that'd be a fine car to replace it with. V8 W-bodies were on my shortlist because I think the concept is absolutely silly.

http://www.autotrader.com/cars-for-sale/vehicledetails.xhtml?listingId=443168761&zip=44070&modelCode1=GP&referrer=%2Fcars-for-sale%2Fsearchresults.xhtml%3Fzip%3D44070%26engineCode%3D8CLDR%26showcaseOwnerId%3D72401%26startYear%3D1981%26listingType%3Dused%26endYear%3D2017%26modelCodeList%3DGP%26makeCodeList%3DPONT%26modelCode1%3DGP%26mmt%3D%255BPONT%255BGP%255B%255D%255D%255B%255D%255D%26listingTypes%3Dused%26showcaseListingId%3D448125541%26makeCode1%3DPONT%26engineCodes%3D8CLDR%26firstRecord%3D0%26searchRadius%3D200&showcaseOwnerId=72401&listingTypes=used&showcaseListingId=448125541&startYear=1981&numRecords=25&makeCode1=PONT&firstRecord=0&endYear=2017&searchRadius=200&makeCode1=PONT&modelCode1=GP

Here's one with the same mileage in OH for $8k.

I'm tellin' ya, between me and two of the people I work with, if you don't want it, get us a phone number, one of us'll probably buy it.

Heck, if the $600 car has the same fugly chrome wheels as that Autotrader car, sell 'em, put steel wheels and hubcaps on it like a W-body should have (and eliminate a major problem at the same time - chromed wheels SUUUUUCK for rim leaks), and I could probably scrounge enough leftover stock pistons and rods to convert that engine to 5.7l for free if the LS4 casting is like the other aluminum 5.3s and can be bored out to LS1 size.

Not that the 4T65 needs to be abused more, but that's what torque management in the computer is for. If it were mine, I wouldn't just disable torque management, I'd crank it up more. I'd also leave the DoD alone because it really does work well if you drive in the parameters where it functions.