5.3 L84 vs 3.0 LZO Reliability?

[tjonesdfw]

What does everyone here think is most reliable... 5.3 OR 3.0?  After a prolonged period of electrical issues with my 5.3 Sierra (all documented on this forum), I was on the cusp of trading for a 2024 6.2 L87 truck when the recall hit the fan.  I had been quietly monitoring the issue because we also own a GM SUV with the 6.2 which ended up being under the recall.  Not wanting to end up with two vehicles with potential engine issues, I thought I would just wait to trade until 2025 or 2026, but now I'm told that the 2025 6.2s are blowing up too.  I've been reluctant to consider the 3.0 Duramax because most of my trips are relatively short; 12-14 miles one way, with a longer highway trip once or twice a month, but drive on average 15K-18K miles a year.  I've had guys in the office with multiple blown 6.2s, but also several with repeat issues with coolant control valves on LM2 and LZO 3.0 Duramax trucks, all with very long times at the dealer.  I'm at my wits end with GM, and worry I'm just trading one problem for another if I traded the 5.3 with electrical gremlins for a new LZO Duramax that needs a backordered coolant valve every 30K to 40K miles.  Unfortunately I cant get a 5.3 in the AT4 or AT4X, so I would be forced into another Denali if I stuck with the 5.3. I also hear rumors the 6th gen gas small blocks in the 2027 will have more emissions equipment such as EGR, which sounds like an even bigger mistake.  Wondering if its time to jump ship and go somewhere else.  

Edited July 7, 2025 by tjonesdfw
Forgot a line

[wxman13]

I don't know where you go, all the manufactures are having issues with recalls, you see one of them each week recalling lots of vehicles. I have the LZ0 Duramax in my 2024 GMC Sierra, love the truck and fuel mileage so far, but now at only 2200 miles I have a oil leak, my dealer is working on trying to figure out where its coming from, certainly hope its not the rear main seal, pretty sure the transmission will have to be removed if it is. 

[garagerog]

You can always go one of two ways, go 3/4 ton and get the reliable but gas guzzling 6.6 gasser or go over to the dark side and get a blue oval F150 in Lariat trim that comes standard with the 5.0 liter 400 hp Coyote V-8. Last fall I flew across country to Wa. state to check on the old homestead and since I was going to be driving in some rough pasture land I reserved a p/u. Upon arrival at the airport Enterprise put me in a super crew F150 4x4 in Lariat trim. Being a GM guy all my life I wasn't all that familiar with the Ford trim offerings so when I got back to the hotel and popped the hood I was expecting to see the 2.7 V-6, maybe the 3.5 if I was really lucky, but holy cow Batman I counted 8 intake runners and coil packs and no damn HVAC turbo ductwork! That base Mustang GT motor in that p/u made it really rip, sounded good too, when you opened it up even with the single exhaust system you could swear it had duals with turbo mufflers. I like that Ford has a dash gear indicator for all the forward gears 1-10 on their 10 speed. That 4x4 Ford had a 10" ground clearance, I needed 11" as I managed to bounce the front skid plate off a rock hidden by dirt, but it did it's job, no diffs, oil pan, or transfer case harmed in testing. I put on around 700 miles on that rig and managed close to 21 mpg, although I wasn't exactly driving it for mpg, it put a big smile on my face to flog that Ford! The Lariat trim isn't cheap but has some nice bells and whistles like fully automatic folding mirrors.

[Jus Cruisin]

My neighbor has the LZO in his Yukon and is over 20,000 miles all trouble-free. I went from the 6.2l to the LZO and so far so good. I have just under 2,200 miles on it. I love the fuel economy and the less expensive per gallon cost, too. 

[newdude]

39 minutes ago, Jus Cruisin said:

My neighbor has the LZO in his Yukon and is over 20,000 miles all trouble-free. I went from the 6.2l to the LZO and so far so good. I have just under 2,200 miles on it. I love the fuel economy and the less expensive per gallon cost, too. 

 

 

LM2 unless his Yukon is a 2025.  Yukon has had the LM2 from 2021-2024.  

[newdude]

L3B Turbomax FTW.

 

In all seriousness, 5.3 has swayed somewhat back into the reliability realm as of the 2024/2025 window.  The 3.0 Duramax gets great mileage even with your described driving but I'd steer one towards someone who drives 20+mi one way a day and keeps city and stop and go driving on the lower end.  I know GM and its engineers say stuff like that "isn't an issue" but IMO it still is.  

 

If I had to throw coin on a brand new truck right now, its the L3B Turbomax or the 5.3.  I love the 3.0 Duramax, don't think I'd want to deal with diesel emissions equipment again.  Did it on my 2016 Colorado Duramax with an 8 week wait for a part once before.    

 

As far as jumping ship?  Its all going to get more complex no matter the brand.  Plus if you spend almost 16 years in the industry, you realize they all have their potential or widely known problems.  Gas particulate filters are on the horizon for the US and some manufacturers are already using them (Ford threw one on the Maverick with the 2.0 turbo). 

 

Toyota seems to have hammered out their 3.4 TT V6 issues they had the first year or two (assembly/machining just like GM and the 6.2s). 

 

Ford's 2.7 Ecoboost and 5.0 Coyote seem to be their most solid options. 

 

Ram?  Its either the headache Hurricane which has had plenty of first/second year problems or you wait for the Hemi to hit the lot again.  

Edited July 7, 2025 by newdude

[tjonesdfw]

1 hour ago, garagerog said:

You can always go one of two ways, go 3/4 ton and get the reliable but gas guzzling 6.6 gasser or go over to the dark side and get a blue oval F150 in Lariat trim that comes standard with the 5.0 liter 400 hp Coyote V-8. Last fall I flew across country to Wa. state to check on the old homestead and since I was going to be driving in some rough pasture land I reserved a p/u. Upon arrival at the airport Enterprise put me in a super crew F150 4x4 in Lariat trim. Being a GM guy all my life I wasn't all that familiar with the Ford trim offerings so when I got back to the hotel and popped the hood I was expecting to see the 2.7 V-6, maybe the 3.5 if I was really lucky, but holy cow Batman I counted 8 intake runners and coil packs and no damn HVAC turbo ductwork! That base Mustang GT motor in that p/u made it really rip, sounded good too, when you opened it up even with the single exhaust system you could swear it had duals with turbo mufflers. I like that Ford has a dash gear indicator for all the forward gears 1-10 on their 10 speed. That 4x4 Ford had a 10" ground clearance, I needed 11" as I managed to bounce the front skid plate off a rock hidden by dirt, but it did it's job, no diffs, oil pan, or transfer case harmed in testing. I put on around 700 miles on that rig and managed close to 21 mpg, although I wasn't exactly driving it for mpg, it put a big smile on my face to flog that Ford! The Lariat trim isn't cheap but has some nice bells and whistles like fully automatic folding mirrors.

If I could fit a 6.6 gasser in my garage when in town I would own one in a heartbeat compared to all the half ton offerings.  Wanted to buy a 5.0 F150 in 2021 but only a moron would have paid the 10K dealer markup they still had around here at the time.  It sure did sound healthy for as small as it is.  Wondering how long Ford keeps that 5.0 alive though.  

[tjonesdfw]

14 minutes ago, newdude said:

L3B Turbomax FTW.

 

In all seriousness, 5.3 has swayed somewhat back into the reliability realm as of the 2024/2025 window.  The 3.0 Duramax gets great mileage even with your described driving but I'd steer one towards someone who drives 20+mi one way a day and keeps city and stop and go driving on the lower end.  I know GM and its engineers say stuff like that "isn't an issue" but IMO it still is.  

 

If I had to throw coin on a brand new truck right now, its the L3B Turbomax or the 5.3.  I love the 3.0 Duramax, don't think I'd want to deal with diesel emissions equipment again.  Did it on my 2016 Colorado Duramax with an 8 week wait for a part once before.    

 

As far as jumping ship?  Its all going to get more complex no matter the brand.  Plus if you spend almost 16 years in the industry, you realize they all have their potential or widely known problems.  Gas particulate filters are on the horizon for the US and some manufacturers are already using them (Ford threw one on the Maverick with the 2.0 turbo). 

 

Toyota seems to have hammered out their 3.4 TT V6 issues they had the first year or two (assembly/machining just like GM and the 6.2s). 

 

Ford's 2.7 Ecoboost and 5.0 Coyote seem to be their most solid options. 

 

Ram?  Its either the headache Hurricane which has had plenty of first/second year problems or you wait for the Hemi to hit the lot again.  

Appreciate the advice, especially from someone in the trenches.  All told, the electrical issues on our 5.3 never left me on the side of the road, and only put it in the dealer when I wanted.  I guess that's all you can ask for these days.  

 

I've owned every truck brand but Toyota (none without issue) and I'm certain they're all going to get more complex by the year.   I had a Ram that liked to eat plastic capped radiators and fry tail light circuit boards nearly every few months.   Also had an F150 with the 5.4 that had the top end re-built 3 times for collapsed lifters and god knows how many cam phasers, but then went to a 3.5 Ecoboost that ran like a top for tens of thousands of miles before starting to need cam phasers.  Before this latest Sierra, we had a GMC Canyon Denali that filled up the floorboards like a bathtub every time it rained or went through a carwash... 4 repair attempts only to find out the firewall was mis-stamped from the factory and the dealer bought it back.  Now a 5.3 Sierra with gremlins and a 6.2 SUV that could give up the ghost.  Nothing is immune!

 

Definitely leery of the modern diesel emission equipment too after seeing the issues with fleet trucks in our industry... almost all of them are going gas now.  Not sure how I feel about gas particulate filters that many say are coming on the 6th gen smallblock and others... going to be an interesting couple of years.  

[Jus Cruisin]

15 hours ago, newdude said:

 

 

LM2 unless his Yukon is a 2025.  Yukon has had the LM2 from 2021-2024.  

It's a 2025. He runs up to his cabin near Traverse Bay from metro Detroit a lot. 

[Atlas]

I'm rolling the dice on an LZ0. If it turns out to be a problem child, I'll get something else. I love the way it pulls nice and low, it just feels so much better than a 5.3 in these trucks.

 

If solid reliability and simplicity was my goal, I'd be after a 6.6 in a GM offering, or a 5.0 in a Ford. GM's 6.2 is a wait and watch for me, have they truly solved the issue? I'll be miffed if my Camaro is affected, I really don't want a dealer tearing into my weekend driver/garage queen.

 

Wouldn't touch a Stellantis product with a 10' pole. They need to find themselves.

[PunchT37]

Everything is gonna be more complex [govt regs]. Modern diesel at the top of the list. I choose the L84 if staying GM.

 

5.0L Ford has belt drive oil pump. We`ll see on that, as miles pile up.

Edited July 8, 2025 by PunchT37

[Z45]

Almost 1 yr with my LZO and its been flawless and 26.6 mpg in the first 7,500 miles. Have friends (3 but 1 just got a 25 LZO) with the LM2 and they have not had any issues.  But I suppose I should qualify this, all of them are retired (over 60) as I am I so no messing with tires, exhaust, suspensions etc, we just drive them.  Btw, all those who say the diesel has more maintenance are not correct.  The engine only takes 7 qts of oil and I get about 1,000+- miles on a gallon of DEF so it averages out.  Fuel is in the low $3 whereas the 6.2L (17mpg) I was paying over $4 gallon for 91 here.  About 200+ miles on a tank of fuel, 700 range.

 

PS - If you are concerned about the 3.0L then don't get one. You will pressure yourself into coming up with problems.  

 

 

Edited July 8, 2025 by Z45

[redwngr]

My '23 LZO is a little over 30,000 miles. 

(had an LM2, but convinced myself I 'needed' the new dash/interior)

If I need another truck tomorrow, it will be another LZO. 

Trying to convince the better half that she needs a Yukon with the LZO

 

 

 

 

Edited July 8, 2025 by redwngr

[Port Tack Farm]

I've had my 24 Sierra SLT with the LZ0 for a year now and surprising already have 19K miles.  They have been all trouble free and the truck has been flawless.  I came out of a 2017 Yukon Denali the the 3.6 liter and it was a great truck.  I put 112K on it before we sold it to our daughter and her husband, and other than a transmission issue around 40K miles, fixed with a full flush and refill, it was flawless.  I think he's got nearly 140K on it now and still running strong. 

 

Back to the LZ0 on my Sierra, I average 28 mpg most to the time.  Diesel in my area runs $3.09 a gallon so it's been very economical to run.  I refill the DEF tank when it drops below 1/2 and I'm filling it every 2.5K-3K miles.  Oil changes are a breeze too with the drain plug and filter right there.  I expect I'll need to replace the fuel filter in a few months.  Most of our miles are highway between our home and our farm about 50 miles away, but it's also become the go-to for longer distance trips instead of my wife's Audi Q5.   I absolutely love this truck.  It's a standard bed with Max Tow so it's also a workhorse when I need to tow or haul something.  I strongly considered getting a 3/4 or 1 ton with the 6.6 gasser but the cost of entry vs my 1/2 ton and the expected fuel expense at 12-15 mpg were just to hard to swallow.  I may still need to jump up to the 2500 or 3500 at some point if i end up maxing out my tow capacity on the 1500, but I'm pretty happy now and hope I won't have to trade up in size.