2020 6.2L: misfires, lifter issues and engine replacement

my wife's 2020 tahoe started giving episodic check engine lights and had a rough idle a couple weeks ago. i do basic maintenance on this car and change the oil every 5k mi and oil filter every 20k mi. engine oil level looked fine, and when i used a scan tool (launch x431) it didn't show any notable engine-related trouble codes. as a result of having so little to go on for diagnostics, i had her take the car to a nearby dealership last friday.

the dealership takes 4 business days to make a substantive diagnostic response, where they eventually note some historical misfires, that they're checking spark plugs and fuel injectors, and a cylinder has low compression and is being tested for leaks. after 5 buiness days, they say "we removed the valve cover and found some sludge built up" and "there is a stuck lifter in engine. recommend replace engine". the quote to replace the engine is $14k.

based on what i know about the 2020 tahoe, i am to understand that stuck lifters that require replacement is not an uncommon scenario, but suggesting a wholesale engine replacement seems ridiculous. i did some searching here on the forum and found this recent thread where it sounds like a similar scenario has led to the (questionable) suggestion of an engine replacement from a dealership. as a result of what i read in that thread, i plan to get a 2nd opinion from an independent shop.

i appreciate any input here, thanks for reading.

What oil filters are you using that last 20k miles?

I've got to know why you wouldn't change the filter at every oil change. Such a minimal cost compared to 8 quarts of quality synthetic motor oil. The standard dealer response is engine replacement with a stuck lifter due to the probability of the camshaft being damaged also.

Fless said:

What oil filters are you using that last 20k miles?

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Fram xg line says they're good for 20k and their fe line says 25k but why someone would go that long especially when changing the oil multiple times throughout that period.....

I use their fe line in my vehicles but it gets changed every 5k with the oil. Oil and filters are cheap compared to cam and lifters or a new motor.

persistent said:

... "there is a stuck lifter in engine. recommend replace engine." the quote to replace the engine is $14k.

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There is something fundamentally wrong with an engine's INITIAL design specs,
such that when a SINGLE lifter gets stuck, the pound of cure is to replace the engine entirely.

In an ideal world, replacing that stuck lifter alone should be enough.
Do keep in mind, especially given the GenV 6.2L suicide issues lately,
that the fix you should be considering is to replace the two-mode lifters
with the lifters used in the 6.6L L8T (yes, this would require an ecm tune).

Holy crap! Oil filter every 20k????? REALLY??

Not trying to be mean, but come on man, you're down there anyways. This is probably the most worrysome post I've read in a long time. "I do my own maintenance every 5k, but NO filter."

You dealership diagnosis of SLUDGE is 110% correct. That filter isn't doing anything after 5000 miles normally. Then almost nothing at all after your oil change. Then almost nothing after the first 500 miles of your current schedule of filter change.

You need to be very careful at this point......change the oil AND filter with new. Then add some ATF or SEAFOAM and run for 500 miles. Change oil and filter. Do again for 1000 - 1500 miles. Change oil and filter. Do again for 3000 miles. Change oil and filter.......

Then stick with 5k, or less, with oil AND filter and you should be good. Your "cost savings for a 20k filter" just cost you WAY more. Don't belive all the filter advertised hype......it's a bunch of BS by marketing people who know Jack S H i T about engines.

Sorry to be so harsh, but this is reality if you want to be a DIY guy. 30 yrs experience speaking....

persistent said:

i do basic maintenance on this car
and change the oil every 5k mi
and oil filter every 20k mi ...

dealership said:

"we removed the valve cover and found some sludge built up"

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I freely admit to not reading this slowly enough the first time.
If it makes you feel better, find THE ABSOLUTE CHEAPEST oil filter,
and change it every time you change the oil.

Engines cost more than oil. Engines cost more than oil filters.
Q.E.D.

B-train said:

Holy crap! Oil filter every 20k????? W T F ??

Not trying to be mean, but come on man, you're down there anyways. Do you trip over $100 bills to pick up dimes too? This is probably the most absurd post I've read in a long time. "I do my own maintenance every 5k, but NO filter."

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^X2
He should not be doing any oil changes period.

For sure the sludge was caused by the 20k mile oil filter changes. Wow! I bet if you cut one of those open after 20k miles it would be packed with crap and sludge. No good man.

Common sense says no matter what a filter says it will have the old oil and crap lodged in it just contaminating the engine.

Fless said:

What oil filters are you using that last 20k miles?

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K&N.

i was just going off the packaging that said they were good for 20k mi. if the service interval should be every oil change, that's easy enough to adapt to in the future.

i'm really surprised at the amount of crap i'm catching for not changing the filter more often. my recollection of every car i've ever taken to a dealership is that they definitely would not change the filter every time the oil was changed. telling me i'm an idiot for not changing the filter more often does literally nothing to help me make a decision about the repair.