08 Tahoe 6.0L LFA - Bent Rod??? Is That Even Likely?

[iamdub]

I appreciate your candor and I share your sentiment. But what I can I do about it? I'm at his mercy.

I don't like this being with him any less than anyone else would. Honestly, now I'm concerned that if "sludge" clogged the ports from "detergent" in the oil, that caused the lifters to stick enough to grind down the cam, then ... what about the odd-cylinder side? Will I have to replace that next?

I appreciate you being receptive and not getting butthurt about such candor.

More candor: What can you do about it? You can do what was suggested to you a long time ago- remove yourself from his mercy. It was suggested to you multiple times back before this had been drug out (and escalated?) to get your truck back from him, but your replies every time were you essentially surrendering to and defending him. Why? What power does he have over you? There has been so much BS this guy has been feeding you but you sum it up as just jokes cuz he's just a funny guy. If you want a laugh, buy a ticket for ~$30 and go see a comedian. Don't pay $1,600 multiple times and upwards of $4,000 to a "mechanic" for a laugh. If you had agreed to pay him a big stack of cash to replace the motor, would he suddenly get serious and tell you that he was just joking and that you don't need a new motor, that your piston actually IS reaching TDC and that he didn't really see what he told you he saw with his bore scope? Hell no he wouldn't! He keeps throwing stuff at you until he finds something you're not gonna question paying him to do. If you call him out on his lies and put him in a corner, he easily gets out by laughing it off and convincing you he was kidding cuz you two are just two friendly jokester buddies like that. Then he finds another lie to try on you...

Let's say that there actually isn't anywhere else local for you to take it. You could've gotten it and let it sit parked in your driveway for the past few weeks. At least it wouldn't be at this scammer's place having who-knows-what being done to it and likely racking up an unnecessary bill. It'd be safe under your watch and accessible for you to bring somewhere once you found another shop. I'm not believing that there are no other options for you. Bringing it to a reputable and competent shop a city or two away where it could be quickly properly and accurately diagnosed and quickly and probablly cheaply repaired would far outweigh the inconvenience of having to take it a few miles further.

A sticking lifter isn't gonna grind down a cam. It'll just tick until it unsticks. If it doesn't unstick and gets beat up, then it could come apart and do damage from the fragments going into the oil stream, etc. A sticking lifter could possibly get knocked around and rotated if it breaks the retainer tray. THEN it would grind a lobe because the wheel on it would be be sideways on the cam lobe and not rolling. Picture a car being T-***** and pushed sideways with it's wheels skidding on the road- that's what the roller on the lifter would be doing on the cam. Oh- sanding the head or block or whatever he said he sanded... No he didn't. Doesn't matter if the block is aluminum- the cylinders are steel sleeves. The mating surfaces of the block and heads has to be 'perfectly' flat (within .004", I think is what GM specifies). Also, the heads have to have an RA of something like 20-40, which looks like a foggy mirror. You're not gonna get such surfaces by hand-sanding and especially not while in the vehicle. Just more of his lies and technical jargon being used against you.

 

[tiktok4321]

I got it back today. I *know* that he put a lot of his own money into this job. Saw the wear on the camshaft, and where the next lifter was about to fail. Saw the seized lifters. I know that replacing the camshaft alone was worth $300 plus the lifters and gaskets... He said $3k in parts (I'm guessing more like $1000 wholesale) but the 20 hours in labor (book value to replace camshaft) was worth well over what I paid him.

Am I happy that he's charged me $1600 twice this year? No. Am I happy that he's had the truck for 6 weeks, no. I'll probably not have him work on the mechanical engine again. I really think he should have done the job he did this time 6 months ago - even if it was for $3k.

Though not a rebuild, the new cam, new lifters, new gaskets, - and, yes, replacing a broken lifter tray (I saw it) - etc, is better for $1600 than the cheapest used LFA that I can find at around $3300 - uninstalled.

There are still some issues with the hybrid, but that's minimal at this point. The hybrid can't function correctly unless the engine is pristine, and it's getting there.

So, I really do appreciate the additional candor. Next time I need to service it, I'll likely buy that $3300 engine, swap it out, do a full shop rebuild on the old one and sell it to a drag racer.

 

[992dr]

Isn't the LFA basically an aluminum Gen IV 6.0?
If that's the case, you could've bought any Gen IV 6.0. All, you would've needed was a short block.

Sorry you had to deal with that crap. Hopefully its resolved.

 

[tiktok4321]

OK. I lied. It's still got a dead misfire somewhere and it's not coding. In addition, it stalls out when accelerating sending Hybrid system codes that clear after an hour or so of "nice" driving. Going to get the mount replaced soon, and will then have it examined by the dealer. Went the other day, and actually talked to the tech who had been advising the mechanic who was working on my car.

So here are the current theories:

1) Perhaps the ECM wasn't or wasn't properly programmed after the camshaft replacement, causing the misfire
2) Engine mount busted means that the torque on the engine is tugging at the electrical connections and thus upsetting the hybrid control system
3) Electrical connections to the transmission control unit are corrupted or loose
4) Multiple(?) control modules need hardware and/or software upgrades.

How should I direct the dealer to diagnose? The service writer I spoke to was all over the place (only went to set up an appointment).

BTW, I know we're getting out of the mechanical realm of this engine into Hybrid territory that should be in the other room, but there are so few of these out there...

Isn't the LFA basically an aluminum Gen IV 6.0?
If that's the case, you could've bought any Gen IV 6.0. All, you would've needed was a short block.

Sorry you had to deal with that crap. Hopefully its resolved.

I don't know... I would think you're right, but don't know all the extra little electrical hookups the Hybrid adds.

 

[tiktok4321]

Dead misfire was from Cylinder 7 spark plug misfiring. Got that replaced & new engine mount and exhaust ring installed.

Still getting a minor misfire on Cylinder 7. Again, nothing is bringing up P030x codes, but it's enough to upset my transmission and it occasionally stalls out when accelerating from a stop. I don't like being in the middle of an intersection and losing my ICE.

Could be a hybrid issue, now, but in all honestly, the hybrid runs well as long as the ICE is functioning right. I don't have an expensive code reader - just a Bluetooth dongle with Torque. Running the tests, I have had at least one misfire in just about all cylinders, but low counts - except 7 which is in the 50's.

I don't mind pulling the plug and wire again. Maybe it IS a hybrid issue.

 

[swathdiver]

They could have put the wrong camshaft in there. Do you have the part number of the new one they installed?

 

[tiktok4321]

They could have put the wrong camshaft in there. Do you have the part number of the new one they installed?

Unfortunately, no. I just saw the old one with the worn lobes. But if it were wrong, I'd assume a lot more errors. The truck runs often with ZERO misfires, then 7 will start, then a couple more will have a few hiccups.

 

[swathdiver]

It was common wisdom not so long ago to reuse the original camshaft when deleting the AFM components. This led to misfires at idle because the lobes on the AFM cylinders is .002 smaller, enough slack in the valvetrain to throw codes. It's long been obvious that that mechanic knows so much that isn't so.

Well, let's try the simple stuff first. Swap out one at a time, number 7s plug wire then coil then spark plug with another cylinder and see if the misfire moves to the donor cylinder.

 

[tiktok4321]

Iamdub,

My mechanic is an idiot and I shall no longer patronize his business. After cylinder 7 continued to misfire, I took it upon myself to inspect that side of the engine. I already had a set of plugs and wires. I took out all the odd cylinder plugs and what do you know? Cylinder 7 had the wrong plug in it!!

No new misfires!

Now the rest of my problems are hybrid... Ugh. But rest assured, this gentleman will never ever see my vehicle again.

 

[992dr]

I don't know... I would think you're right, but don't know all the extra little electrical hookups the Hybrid adds.

Man, I wish I knew more about the Hybrid models to help you out.

Iamdub,

My mechanic is an idiot and I shall no longer patronize his business. After cylinder 7 continued to misfire, I took it upon myself to inspect that side of the engine. I already had a set of plugs and wires. I took out all the odd cylinder plugs and what do you know? Cylinder 7 had the wrong plug in it!!

No new misfires!

Now the rest of my problems are hybrid... Ugh. But rest assured, this gentleman will never ever see my vehicle again.

I had a similar issue with a shop that worked on my Tahoe. They screwed up my transmission. I dealt with there idiotic employees for a solid year and gave up. I then spent the next 2 years on a a mission and finally figured it out with the help of a member on ls1tech.
Now I have a hard time trusting mechanics.

That's terrible. Something so simple. What a d**k.