What is the quarts "range" on the dipstick on these trucks?

[jfoj]

@blanchard7684

Oil temps were at 226F for approximately

226F? Goodness.

For how long?

So oil temps were 220F or higher for 1 hour and 40 minutes of my drive. Total drive was around 2 hours and 15 minutes. 31 minutes of the lower temps was due oil warm up from cold start to 220F and lower speeds in town at the end of the drive.

The oil was in the 225F range for 30 minutes of this above timeframe.

The 226F range was for around 20 minutes of the above timeframe.

 

[SuperOldSchool]

Yes and no. 8 quart fill with filter only puts the oil level about 1/3 up the dipstick.

Are you running 0W20 oil?

How many miles on the engine?

How many miles since you last checked the oil?

How much highway driving are you doing?

Suggest you check the oil every 2nd or 3rd fill up.

I run put in 9 qts when I change oil. Puts oil level just slightly above top hash marks on dipstick, gives a buffer for oil consumption and fuel dilution.

I do exact same thing - 9qts

 

[KMeloney]

Any problems with mixing in different viscosity oil with the 0W20? Even if with only a quart of, say, 5W30? (Could you introduce a greater amount, too?)

 

[SuperOldSchool]

No I do it when I’m short … 153k mi on my l86 and no issue. Also I run 5w30 in summers

 

[KMeloney]

No I do it when I’m short … 153k mi on my l86 and no issue. Also I run 5w30 in summers

Incidentally, we're all a bit concerned about our L87s here... Thanks for the info, assuming it holds true for the L87.

 

[jfoj]

I do exact same thing - 9qts

Smart man!

I got roasted when I asked the question about 8 qts not being enough. Granted things may have changed with the oil pan size, but a number of years ago, I think up to about 2015, all the V8 trucks indicated 8.5 qts with filter. Then with a single piece of paper, GM updated the oil fill with filter from 8.0 to 8.5 qts, nothing changed with the motors that had already been been built.

I checked my oil level when I purchased the truck and before the first oil change at 500 miles and matched the level on the dipstick. 8.0 qts did not even touch the stick when I initially poured the oil in. Sure I could have waited until overnight, but this was not my plan.

I run 9 qts and have ZERO issues. More oil to be diluted by fuel, more oil to get dirty, more oil to lubricate the engine. Given all the 6.2l problems are OIL related, this is not going to hurt anything. I also WILL NOT run 0W20 oil in the engine. Either 5W30 or 0W40. After tracking the oil temps on longer highway cruises, I am going to switch to 0W40 and see what happens with oil temps and the oil analysis.

The 6.2l in the Camero's spec 0W40 and the DI 5.3l and 6.2l in boats (doubt they have DFM in these) spec 5W30. 0W20 was speced because GM sold too many 6000 lb trucks and they were worried about the CAFE numbers.

 

[jfoj]

Any problems with mixing in different viscosity oil with the 0W20? Even if with only a quart of, say, 5W30? (Could you introduce a greater amount, too?)

Dump the 0W20 and move up to 5W30 or 0W40. The same 6.2 in the Camero is spec'ed for 0W40. And trust me the Camero does not weight 6000 lbs and run below 1700 RPM on the highway!

 

[KMeloney]

Dump the 0W20 and move up to 5W30 or 0W40. The same 6.2 in the Camero is spec'ed for 0W40. And trust me the Camero does not weight 6000 lbs and run below 1700 RPM on the highway!

I live in PA where we have long winters and summers. Which weight oil is appropriate?

Also, I haven't yet understood the issue with these trucks running at 1700 on the highway. Does/can the oil not get taken up/pumped thoroughly at low RPMs? Or is something else going on?

 

[jfoj]

0W40 would probably be best for the PA Winters and Summers.

The 6.2l is lugging and running at very low RPM and HIGH engine LOADING on the highway. Which puts a lot of load on the rod bearings and sets up a situation for LSPI (Low Speed Pre Ignition) or engine knock.

On the first graph there are clearly quite a few times the engine RPM is much higher than 1700 RPM, even some spikes to 4000 RPM, but I was doing quite the job bobbing and weaving around a bunch of left lane campers that some were not even going the speed limit. But at 75 MPH my 6.2l Yukon Denali XL's RPM is pretty much 1620 RPM! A fast idle, but the transmission typically only downshift to 9th gear, which only brings the engine speed up about 100 RPM, but this causes the engine loading to go into 85-95% load range pulling very sight grades. You would be far better of in 7th gear and the engine RPM being much higher, BUT you will take a hit on fuel economy. This would limit the engine knock as well. So the loading of the engine at the lightweight oil that is operating at 225+F on the highway and extended engine knock, much worse if not running Premium fuel is receipe for disaster.

 

[KMeloney]

0W40 would probably be best for the PA Winters and Summers.

The 6.2l is lugging and running at very low RPM and HIGH engine LOADING on the highway. Which puts a lot of load on the rod bearings and sets up a situation for LSPI (Low Speed Pre Ignition) or engine knock.

On the first graph there are clearly quite a few times the engine RPM is much higher than 1700 RPM, even some spikes to 4000 RPM, but I was doing quite the job bobbing and weaving around a bunch of left lane campers that some were not even going the speed limit. But at 75 MPH my 6.2l Yukon Denali XL's RPM is pretty much 1620 RPM! A fast idle, but the transmission typically only downshift to 9th gear, which only brings the engine speed up about 100 RPM, but this causes the engine loading to go into 85-95% load range pulling very sight grades. You would be far better of in 7th gear and the engine RPM being much higher, BUT you will take a hit on fuel economy. This would limit the engine knock as well. So the loading of the engine at the lightweight oil that is operating at 225+F on the highway and extended engine knock, much worse if not running Premium fuel is receipe for disaster.

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Thanks. Now, I’ve always considered myself a car guy, but I guess I’m just not understanding the term “high loading” here, especially at low rpms. Is that the same as what I’d have called “lugging the engine”? Like if you’re trying to go up an incline on a bike in 10th gear when you should be in a lower gear? If so, ok, but if the highway is flat, then… what’s the real issue? I’d have to think that the transmission and gear ratio and whatnot were designed to operate this way/in this range. But is that THE problem you suspect is at hand here? That that’s way too low of a gear for that speed and that rpm? I guess I always believed that higher rpms, more often, are what harm engines over time — but it sounds as though you’re convinced that the opposite is true here.

…Or is it really all about these engines just not getting enough oil under these conditions?