5.3l Denali Purchase

[Cshults]

Hi all,

New to the forum and am here because I am looking at purchasing a 07-09 Envoy Denali. I'm coming off the last 13 years with my 01 Platinum Edition Bravada and it's been a great, reliable vehicle.

I figured the 5.3l envoy would be at least as solid as the Bravada but have come across some scary stories involving lifters collapsing due to a fuel management system I didn't even know existed on these vehicles, ultimately causing thousands of dollars in repair bills.

The ones I am looking at have between 60k-85k miles on them and appear to be in good/very good condition but pictures always make things look great.

Anyhow, I'm now second guessing purchasing one but from what I can tell it seems like this collapsing lifter problem can be completely avoided by simply disconnecting the fuel management system, is this true?

Secondly, are there any other major telltale things to look for on these vehicles? I want to do the best I can to avoid buying a money pit.

Thanks for any advice

 

[mrrsm]

Welcome to GMT Nation...

If you want to find one that does not have Rust and Body Cancer 'eating it out of house and home' visit this site and find the Zip-Codes for Major Florida Cities (Miami, Jacksonville. Orlando, Tampa Bay Area) and plug those into THIS site and hopefully you'll locate a Good One.

It would be worth finding put how much the Fleet Carrier Transport Fees would be to have the thing transported up to a Local Dealership instead of buying ANYTHING that is a Decade or More in Age and purchasing a NIGHTMARE either from the Rust Belt-Salted Road Regions with Harsh Winters or from a Flood Plain area. The LAST thing you want to become is the "U-Boat Commander" of the "SS Rust-Oleum".

Florida's "Lemon Law" Protection may or may not apply for an out-of-state purchaser of any In-State Used Vehicle. If nothing else... this site will give you some idea on what is available in The Nation that is worth your time and effort researching:

Used GMC Terrain Denali for Sale (with Photos) - CARFAX

Find the best GMC Terrain Denali for sale near you. Every used car for sale comes with a free CARFAX Report. We have 646 GMC Terrain Denali vehicles for sale that are reported accident free, 453 1-Owner cars, and 650 personal use cars.

www.carfax.com

Brian from Briansmobile1 has a Video on his Youtube Channel that explains the problem with "Sticky Lifters" and demonstrates the straightforward method on How To Clean out the Clogged Lifters without requiring an Expensive Repair Bill:

... here is another Video on the topic of the OTHER NIGHTMARE... The DOD and AFM Feeatures that Fail and leave the Owner with the Best Option of DOD DELETION if it becomes the Go-To R&R Option to solve the problem:

 

[Cshults]

Thanks for the reply. I'm definitely open to and would prefer a southern vehicle and will travel for the right one. What are the sites you mention? I don't see any links..

Thank you

 

[C-ya]

If you end up with one, get a $99 tune from @limequat here on this forum and have him disable DOD/AFM. I did on mine. I bought one with 139K miles and it was drinking oil like I drink beer. (As a salty squid, I like my beer!) Six qts in a normal OLM interval - and they hold only hold 6 qts. I should have just put a new filter on and called it good. If you are looking at lower mileage units, they may not be there yet.

 

[Cshults]

If you end up with one, get a $99 tune from @limequat here on this forum and have him disable DOD/AFM. I did on mine. I bought one with 139K miles and it was drinking oil like I drink beer. (As a salty squid, I like my beer!) Six qts in a normal OLM interval - and they hold only hold 6 qts. I should have just put a new filter on and called it good. If you are looking at lower mileage units, they may not be there yet.

Was just reading some posts about disabling the DoD via a connection on the brake booster or via a tune with DoD delete. I like the sound of a tune and waking the engine up a little in the process but seems like the tune comes with some engine knock? Might rather deal with pulling the sensor on the booster and a CEL than engine knock.. Either way it sounds like disabling the DoD solves the potential lifter failure..

 

[mrrsm]

Click on the 'Pale Blue Box":

Used GMC Terrain Denali for Sale (with Photos) - CARFAX

Find the best GMC Terrain Denali for sale near you. Every used car for sale comes with a free CARFAX Report. We have 646 GMC Terrain Denali vehicles for sale that are reported accident free, 453 1-Owner cars, and 650 personal use cars.

www.carfax.com

 

[northcreek]

Hi all,

New to the forum and am here because I am looking at purchasing a 07-09 Envoy Denali. I'm coming off the last 13 years with my 01 Platinum Edition Bravada and it's been a great, reliable vehicle.

I figured the 5.3l envoy would be at least as solid as the Bravada but have come across some scary stories involving lifters collapsing due to a fuel management system I didn't even know existed on these vehicles, ultimately causing thousands of dollars in repair bills.

The ones I am looking at have between 60k-85k miles on them and appear to be in good/very good condition but pictures always make things look great.

Anyhow, I'm now second guessing purchasing one but from what I can tell it seems like this collapsing lifter problem can be completely avoided by simply disconnecting the fuel management system, is this true?

Secondly, are there any other major telltale things to look for on these vehicles? I want to do the best I can to avoid buying a money pit.

Thanks for any advice

Don't let any of these things that you read about on the "interweb" scare you, you are looking at a small sampling of the vehicles that are on the road without those problems. I just traded my 07 Envoy Denali 5.3 (for no good reason) with 125k miles that only threw one code in it's life which was a bad oil pressure sensor $20.
These are great vehicles and have no more problems than any other vehicle that you might consider.

 

[C-ya]

Was just reading some posts about disabling the DoD via a connection on the brake booster or via a tune with DoD delete. I like the sound of a tune and waking the engine up a little in the process but seems like the tune comes with some engine knock? Might rather deal with pulling the sensor on the booster and a CEL than engine knock.. Either way it sounds like disabling the DoD solves the potential lifter failure..

I don't have any engine knock. @limequat updated the fuel tables so I can run 87 or 93. I generally run the cheap stuff and it performs as well as can be expected for a now 200K mile motor. If you intentionally set a code, you should scan frequently to make sure there is not a new code. Jeremy (Limequat) can also do some other magic on these trucks. You would need to send both the ECM and TCM if you want any transmission mods as the V8 has separate controllers. I live in MI and I was in his area so I stopped by and had him do the update.

 

[Mooseman]

You probably read about my experiences. Yes, it knocked and pinged but it only did that for the first while until it learned the engine again.

If the DOD/AFM is working correctly when you buy it, you can mitigate the lifter failing by disabling via the booster sensor temporarily or permanently via the tune, which also wakes this beast up quite a bit.

Don't let DOD scare you from buying a good truck.

 

[TollKeeper]

I am at 186k miles on my Envoy V8. The engine "knock" isnt engine knock. Its piston slap, and -ALL- GM's suffer from it. V6, V8, I4, or I6. The only ones that dont are diesel. It is very normal for the LS engines. 99-03 were the worst, but the miles that these LS engines get speak for themselves.

I am looking at replacing my Envoy with a Denali myself. Looking at a 06 with 115k miles. Hoping to get it cheap! Needs minor work. Current owner says a tow truck hooked up to it wrong, and took the bumper and grill and headlights out. No frame damage. Just plastics!

You cant go wrong with a GM with the LS engine. Just make sure to change the Transmission Fluid, Transfer Case fluid, and front/rear diff fluids religiously, and the truck will not let you down..

 

[Cshults]

Thanks for all the replies guys, feel a bit better about picking one up and I'm checking one out tomorrow evening. An 08 Denali with ~63k on it. Once I settle on one, 3 things will happen..

1) Disable the DoD
2) Have the engine flushed or cleaned to dissolve any gunk that may have built up due to the DoD (read about doing this in another post)
3) Change the trans fluid, transfer case fluid, front and rear diff fluid (and of course the oil)

Just haven't settled on the method of disabling the DoD yet..came across these last night and seems like a really easy way to disable the DoD..

AFM/DFM Disabler - Range Technology

AFM Disabler and DFM Disabler for GM car, truck and suv

rangetechnology.com

Anyone have any experience with the range units?

 

[Mooseman]

No experience but to me, those are expensive for what they do. You have to take it out for e-tests and if it falls out or forget to put it back in, it could activate DOD and could be even riskier if it hadn't been working for a long time and the lifters are gunked up.

For half the cost at lime-swap.com (member @limequat ), you can get a tune to permanently disable it and get a performance improvement at the same time. It's a no brainer.

 

[northcreek]

Thanks for all the replies guys, feel a bit better about picking one up and I'm checking one out tomorrow evening. An 08 Denali with ~63k on it. Once I settle on one, 3 things will happen..

1) Disable the DoD
2) Have the engine flushed or cleaned to dissolve any gunk that may have built up due to the DoD (read about doing this in another post)
3) Change the trans fluid, transfer case fluid, front and rear diff fluid (and of course the oil)

Just haven't settled on the method of disabling the DoD yet..came across these last night and seems like a really easy way to disable the DoD..

AFM/DFM Disabler - Range Technology

AFM Disabler and DFM Disabler for GM car, truck and suv

rangetechnology.com

Anyone have any experience with the range units?

Yes, I had the Range unit on mine for a few years and it worked as advertised. I removed it because I was trying to reset a few monitors to pass inspection and decided not to put the Range back in, went back to AFM with no problems. Don't feel that it's imperative that you remove AFM(DOD). It works flawlessly and you will not be aware of it. The average driver doesn't even know that he has AFM and enjoys his vehicle without a hitch.

 

[Mooseman]

Yes, I had the Range unit on mine for a few years and it worked as advertised. I removed it because I was trying to reset a few monitors to pass inspection and decided not to put the Range back in, went back to AFM with no problems. Don't feel that it's imperative that you remove AFM(DOD). It works flawlessly and you will not be aware of it. The average driver doesn't even know that he has AFM and enjoys his vehicle without a hitch.

Did you actually notice a REAL calculated (not DIC) difference with and without DOD? Literature on DOD said it would improve mileage by 5%. So if you were getting 17MPG, that should go to 17.85%. Not even one MPG. On my Saab, I saw absolutely no difference with and without. Specs are that the system must go back to 8 cyl. mode at least every 10 minutes, which never happens because any little slope turns DOD off. It's a real stupid troublesome system of no value.

 

[northcreek]

I can't say that I saw any real difference with or without AFM but, most of my driving is village and secondary roads, I think that the benefits of AFM would be more measurable by those who do daily interstate highway driving.
It must count for something when they are trying to meet their CAFE numbers but, real world benefits seem to be more smoke and mirrors.

 

[Reprise]

Current owner says a tow truck hooked up to it wrong, and took the bumper and grill and headlights out. No frame damage. Just plastics!

Umm...isn't that what a Denali is? Plastics? LMAO
Seriously, the bumper cover isn't terrible, and the headlamps are the same between trims. The grill is a little spendy, but not hard to find. And aftermarket alternatives are available.

Now if the tow driver had taken out the side steps, somehow...that'd be a deal-breaker

You cant go wrong with a GM with the LS engine. Just make sure to change the Transmission Fluid, Transfer Case fluid, and front/rear diff fluids religiously, and the truck will not let you down..

No argument here. Watch the oil level (they're not stellar on oil control, plus the parts that tend to leak on their own (crank position sensors, oil pressure sending units, valve cover gaskets)). But the rest of it is just 'regular maintenance'. I'd get the TransGo 'orange box' kit put in at some point, and maybe an outboard trans cooler. But I'd do that for an I6 version, too.

There's a reason why "LS swap", when put into Google, returns 1,000,000 hits. There really isn't a better choice when it comes to size, power to weight ratio, simplicity (DOD/AFM notwithstanding), and longevity. If you want to hop one up, it's just like the old SBC - outstanding aftermarket support.

Only downside is that the engine bay of the 360 platform is pretty tight with a V8 in it. Spark plugs especially are a pain (go 'under' the inner fender on the passenger side, and 'over the top' on the driver side).

If you're doing new shocks / upper ball joints, that's a perfect time to go after the plugs, while the springs are out on the psgr side.

For half the cost at lime-swap.com (member @limequat ), you can get a tune to permanently disable it and get a performance improvement at the same time. It's a no brainer.

This is the way I'd go, for sure, and he charges the same price for the V8s as he does for the I6. Best deal around.

 

[northcreek]

Only downside is that the engine bay of the 360 platform is pretty tight with a V8 in it. Spark plugs especially are a pain (go 'under' the inner fender on the passenger side, and 'over the top' on the driver side).

Amen to that, I wasted a perfectly serviceable Saturday morning trying to locate the coolant block drains using mirrors and every possible angle to no avail. If I could have found an opening to even "see" one, I doubt if I could have got a wrench on it. Fortunately the plugs were good for 100K before I had to test out new swear words....

 

[Bow_Tied]

The 5.3 Envoy checks all the boxes. When all is well, I love this rig. All is rarely well. It is with certainty that is the low ebb in reliability for all GM vehicles I have owned from the 70s, 80s, and 90s. For reference, my previous 3 GMs were S-series Jimmys which are not known for high reliability but certainly exceed the envoy. I love this rig... but cannot recommend it. Perhaps the '07+ were better than '06 I have. Good luck.

 

[littleblazer]

Not a 5.3 but I put roughly 50k miles on the TB last year and did nothing but add fuel and oil... i only have one 5.3 and it's an LT based one however I've had several 6.0s. AFM is annoying, i can hear the lifter tick and feel when it drops out on the new truck but it does work... aside from leaking like a SOB, one of the 6.0s has 270+ on it and the other 220ish and doesn't use a drop of oil between changes. It depends on what day of the week the thing was built lol. It's a pretty solid driveline.

 

[DocBrown]

I have an '08 Sierra with the 5.3. The same engine as what you are looking at in an Envoy Denali. The DOD/Lifter issues are real. However they are a very small percentage of them. I bought mine with 85k on, it now has 153k and running as good as new.

There is another issue where oil loss is also a prominent "feature". This scared a lot of folks into doing expensive lifter replacements that weren't necessary. The driver side valve cover has a design that allows excess oil into the combustion chamber. It doesn't blow smoke but it causes the #1 and #7 plugs to foul out and cause misfires. In time it will throw codes. This valve cover design is also related to the DOD, but the fix is a replacement cover that changes how the oil flows.

Mine has this issue. As I get older I'm less inclined to tear things apart, so I replace the #1 and #7 plugs every 6 months. Of course my truck is full size so they are easy to get at and it's a 10 minute job.

Also I switched to synthetic oil at about 100k and any lifter noise that was there really quieted down.