2.7L Turbomax teardown

Grumpy Bear · September 25, 2025

Correct. We look for several things to be true at the same time and it is also true we have to give a few a good old fashion educated guess. Emphasis on EDUCTATED.

Enough viscosity. Enough Anti-wear and enough solvency. We can get enough viscosity in any oil by the grade we select and knowing what our targets are. The second one doesn't shout out at you. You have to stay current on the API and ACEA specification. Google is good for that. Some oil actually say. Mobil 1 Euro FS 5W40 is 'FULL SAPS". Not yelling, how it is presented. The last, solvency is the sticking point of most shelf oils. They don't have any. The exceptions I noted. Havoline Pro-RS and Renewable Lubricants BioSyn are required by law to contain a minimum 25% organic ester. Valvoline is an outlier. Chemical cleaning without an ester. Don't ask me how but it works. The remainder that are not shelf oils will either say OR will show up as an oxidation level over 30 units on the virgin oil sample. Google is your friend there too.

My personal selection is 82 on oxidation.

silveradosid · September 26, 2025

i don't think there is any oil that could help , this was a daily rental that had the crap ran out of it. which explains the neglect on the roller. typical rental being beat to death

asilverblazer · September 26, 2025

16 minutes ago, silveradosid said:

i don't think there is any oil that could help , this was a daily rental that had the crap ran out of it. which explains the neglect on the roller. typical rental being beat to death

I don't think this would do it.

The oil life monitor SHOULD account for driving conditions/characteristics/environment and require sooner oil changes.

The results are:

1. The oil life program wasn't engineered well enough

2. It wasn't followed

3. Engine specifications whether mechanical or fluid weren't sufficient

...or combination of any of those.

My guesstimate, is mostly #2.

PunchT37 · September 26, 2025

Can the HPFP leak gas into the oil?

newdude · September 26, 2025

39 minutes ago, PunchT37 said:

Can the HPFP leak gas into the oil?

If the seals leak, yes. The Gen V small blocks have been known to do this on occasion. Pump leaks fuel and when you pull the dipstick it will show overfilled and smell strongly like gas in the oil.

Grumpy Bear · September 26, 2025

3 hours ago, newdude said:

If the seals leak, yes. The Gen V small blocks have been known to do this on occasion. Pump leaks fuel and when you pull the dipstick it will show overfilled and smell strongly like gas in the oil.

Not always. Dizzy was a 8% by GC. never smelled, never showed over full. Just quietly ate herself. Gas killed the viscosity. Who knows how long before consumption outpaced the leakage.

PunchT37 · September 26, 2025

Not sure if that 2.7 was taken care of. Gas will kill the oil. That thing had everything roasted. Head seemed to be clean. Oil pan showed a different story.

Maybe fuel contaminate with long oci?

Every bearing and turbo destroyed. Lots of black in the pan with glitter. Hmmm. Lack of maintenance with a fuel leak to "clean" the top end? Rocker sure wasn`t happy.

Someone run a flush after engine was toast?

Turbo was about to take the whole engine out anyway.

customboss · October 1, 2025

On 9/26/2025 at 5:23 PM, Grumpy Bear said:

Not always. Dizzy was a 8% by GC. never smelled, never showed over full. Just quietly ate herself. Gas killed the viscosity. Who knows how long before consumption outpaced the leakage.

Gasoline in his fuel not only affected viscosity but it also shellacked the heck out of the internals including his rings and cylinders. EGR, valves, and PCV plumbing. Its not just a design issue its a service issue because people think observing without analyzing is enough. He didn't do oil analysis until he paid me to do it for him and it was pretty much too late.

customboss · October 1, 2025

On 9/23/2025 at 10:36 AM, Grumpy Bear said:

146K miles to destruction. So a few questions.

1.) How many of those miles was that rocker "ticking"? (had to be awhile as the axle was half gone).

2.) At that number of miles is this still a "defective part" that slipped through manufacturing/assembly final QC?

3.) Are the prematurely wiped out bores, baked rings, worn on rocker axle etc. due to an oil that was doing its job?

While you ponder this remind yourself that the oil was changed often enough to prevent ALL rocker and timing cover deposits so it wasn't getting extended changes. It wasn't even getting 7.5K changes and stay that clean.

Engine oil does not stop this. Someone just sat and drove it.

TheRiver · October 3, 2025

I'm still interested/intrigued by this engine.............if'n I need to buy before I want to.

newdude · October 4, 2025

3 hours ago, TheRiver said:

I'm still interested/intrigued by this engine.............if'n I need to buy before I want to.

They've been a rather good engine in the field. Sure, its got its issues (which engine doesn't these days) but it really has been pretty good. Plus 2024 and newer its the only gas engine in the 1500 pickups that offers a 5 year/100k mile powertrain warranty. Same warranty time as the 3.0 Duramax.

silveradosid · October 4, 2025

so 5 years to refine this engine and offer a better warranty. was gm as comfortable with this engine in the first gen and know they could push more out of it. i am over 100k miles on my 2020 and other than the oil separator failure it has been good. i am going to switch to valvoline restore and protect to see if i can reduce the oil consumption. which isn't really bad but i think it should not use a1.5 quarts in 4500k miles

newdude · October 4, 2025

2 hours ago, silveradosid said:

so 5 years to refine this engine and offer a better warranty. was gm as comfortable with this engine in the first gen and know they could push more out of it. i am over 100k miles on my 2020 and other than the oil separator failure it has been good. i am going to switch to valvoline restore and protect to see if i can reduce the oil consumption. which isn't really bad but i think it should not use a1.5 quarts in 4500k miles

I'd say the 2022.5 updated to the HO/Turbomax was an indication that they knew the 19-22 had some limits to it perhaps, at least in terms of trying to get more power out of its original form. Hence the beefed block, crank, bearings, etc. The Cadillac variant even gained the benefits from the Turbomax/HO upgrades from looking in the parts catalog but still maintains its 325hp/380tq and 91 octane or higher required. Strange they never seemed to make an announcement though for the engine enhancements.

Edited October 4, 2025 by newdude

GETGONE · October 4, 2025

I thought the engine output was strictly from the engine tune. That's why originally there were 3 tunes in the Colorado. The base motor, a mid HP and the HO version which were even dealer programmed and not from the factory that way.

newdude · October 5, 2025

1 hour ago, GETGONE said:

I thought the engine output was strictly from the engine tune. That's why originally there were 3 tunes in the Colorado. The base motor, a mid HP and the HO version which were even dealer programmed and not from the factory that way.

Quick history.

L3B debuted for 2019. Truck and car usage. Truck and CT4 non V model was 310hp 348tq, 87 octane. Cadillac CT4-V got a bump in power, 325hp 380tq, 91 octane.

2022.5 truck refresh happens. L3B gets an evolution to 2.7 High Output. Oil flow improvement, 30% stronger forged crank, fully forged bottom end and stiffer block (2kg heavier).

Colorado and Canyon next gen debuts for 2023. Canyon only gets the new 2.7 HO. Colorado got 3 variants off the updated L3B basis (HO). L2R was the base 2.7. 10psi of boost, no piston squirters, but otherwise the bottom end is the same as the HO.

L3B then came in two flavors in Colorado. Turbo Plus 310hp 390tq, and High Output 310hp 430tq. Turbo Plus and HO are the exact same engine just slight tune variation. Turbo Plus hits its 390tq at 2000rpm, 20psi max boost, HO hits its 430tq at 3000rpm, max boost 27psi. If you bought a Turbo Plus you could fork over I think it was $500 for the flash to the HO tune, sold through the accessories catalog.

2024 they chopped off the Turbo Plus for Colorado, so L2R and L3B Turbomax only.

2025 they chopped off the L2R, Colorado goes Turbomax only.

1/2 ton trucks never got the Turbo Plus. They went from the original 2.7 form for 2019-2022, then 2022.5 refresh to current to the HO/Turbomax updated 2.7.

Best I can tell for the Cadillac L3Bs, the power ratings stayed as when it came out for the car, but it did gain the HO/Turbomax construction upgrades for what seems to be the 2023 model year.

Edited October 5, 2025 by newdude