Just drained 10 quarts of oil from my L8T

[BuckWallace]

I guess my main concern is that if any damage was caused by the overfill and/or wrong oil, when is it going to become apparent? The only way to tell if anything has been damaged is to tear the engine open, which I definitely would not want them to do. I can just see something popping up five years down the road due to premature wear because of this, then I'm SoL since I'm out of warranty. 

[Chuck FB]

I'm with you on your line of thinking in the scenario where if they really did F up and put in the wrong oil that was never recommended for a good reason for these gas engines. I don't know if its physically possible to 100% see the initial signs of damage by a bore scope into each cylinder as I gather this type of pre-igntion is happening just above the compression ring rather than with old school pre-igntion which started melting/flaking off parts of the top of the piston. Having said that don't take my word for it as I am not a mechanic but have seen some ugly photos/videos of what can happen with this low speed pre-ignition if a very wrong additive package type oil was used. It may have been the tribologist Lake Speed Junior on one of his episodes that showed that type of damage. In an instance like this I don't know if lets say GM ( although it would be the dealerships fault, not corporate GM ) would offer a long term engine warranty or if they would want to just make it all go away and claim there is nothing to see here and shuffle you out the door, I have no idea.

 

It is also a good question about the over fill aspect, each engine design would have its limitations to how much extra oil it could hold before odd things start happening, I am only "guessing" that with an engine of this size and two quarts over filled, perhaps it could cause a bit more misting of oil in the crank case and more of that finding its way into the pcv system and the air/oil separator system in the valve covers and then more oil mist able to get into the intake and onto the back side of the intake valves. Having said that, think of an engine attitude when its climbing up a steep off road hill, that oil is piled up in the back of the sump, or pointed down hill its sloshed to the front, yet there is room down in the pan to allow for that and not cause any major issues ( until the vehicle rolls onto its side or upside down ).

[Another JR]

3 hours ago, Chuck FB said:

New member here, I decided to sign up after some months of reading mostly through this particular GM forum since its official that I bought the truck I had ordered back in Oct and have it in my possession for over a week now. I believe I will have two free engine oil changes available to me within the next 12 months but I am one that is leery about bringing a perfectly good operating vehicle to a shop, certainly not some shady oil change place. Unfortunately even dealerships are not immune to screw ups as after all the people in the oil change bays are from what I understand anyway as typically new hires with often minimal if any experience prior, nor are they mechanics but they may have desires to go into that trade. 

 

If you kept that old oil filter, hang onto it as well as the used oil but don't cut it open. Get that oil sample done and back into your hands and then go from there. My fear and don't mean to go fear mongering, but lets say it turned out to be diesel rated 15W-40, it in theory may have a higher additive package as per zinc etc that could cause low speed pre-ignition that the Dexos 1, Gen 3 oil is designed to prevent. At this point one can just hope its the correct oil but with two quarts excess, otherwise if not its to the dealer to explain what was found in your engine and a course of action they would take.

 

Speaking about oil levels on my new truck, again because of this forum talking about their findings with some fluids being low from new, I went over my truck to check things out. Before it had left the dealer I happened to talk to the service manager who's background is a GM mechanic ( but I had never met him officially until that moment ) and we were talking about some of the issues with vehicles in general in the last few years, yes the valve body issue in the 10 speed HD etc and he said they had a couple of rear diffs/wheel bearing ends blow up on them a couple of years ago due to too low a factory fill and claimed that now they make a habit to check the oil levels. Now granted maybe he thinks they are doing that when bringing in new trucks but sadly my truck proved otherwise or mine slipped through the cracks. Engine compartment wise accessed fluid levels were all good as per engine oil 1/8" above full, brake fluid full, power steering fluid in the middle of range, coolant good. However the rest of the driveline varied and of course a pain in the butt to do the auto trans but did that as well just to be sure. All levels taken on a flat shop floor with fluids having sat over night ( other than the auto trans check which is done hot ) using a wire bent at 90degrees and measuring tape.

 

Front diff ; 1/2" low

Auto trans ; right on level after a whole procedure ( can explain that after )

Transfer case ; approx 3/8" low and also measured what I had to add which was about 200 ML

Rear diff ; exactly 1" low ( for F's sakes ... )

When you say “low,” do you mean distance below the bottom of the fill hole or distance below the bottom of the specified acceptable range, which might be 1/2 inch below the bottom of the hole (don’t remember the real value)?

[Chuck FB]

13 minutes ago, Another JR said:

When you say “low,” do you mean distance below the bottom of the fill hole or distance below the bottom of the specified acceptable range, which might be 1/2 inch below the bottom of the hole (don’t remember the real value)?

Now that you say that, I should have clarified from where I was calling the full mark and how far down the levels were from full, on the front and rear diffs and the transfer case. So from the considered "full" level as per the bottom of the threads of the fill ports is where I was referencing from. I know I have seen some specs in the past as to the lower acceptable range on the diffs as well as the full mark claiming to be at the threads on the diffs. Oddly I can not find any full level spec in the owners manual that has the limited amount of maintenance information, nor do they even say what the oil volumes of the diffs are or even what type of oil, "see your dealer" seems to be the theme there. However it does happen to state in the manual that if the transfer case level is found to be below the fill plug threads that the course of action is to fill it to the threads but they don't give a lower acceptable value which may mean they don't really have a lower level limit on it, just make sure its full. In topping up the diffs, the factory oil is 75W90 rear and they call for 75W85 front but of course 75W90 has been run for years in the front diffs, its all about getting that last little bit of fuel mileage. Anyway I wasn't too worried about the front since it wasn't going to take much volume and used from my five gallon pail of 75W90 I use in highway tractors and so on with the pump on it, same for the rear. Its the rear diff out of everything that concerned me as being well below any spec I have come across and yet it seems to be a theme and have seen mechanic youtubers that have bought an HD truck and they found the same thing with the oil being down 1 inch when they measured it.

 

It would be nice to have access to a shop manual, not that I would understand all the jargon but there would be a lot of invaluable information in it.

 

By the way the automatic trans, I had it up to temp and then pulled the check plug on the bottom and only the dribble from its stand pipe came out so there was no way of knowing where the level really is, is it there or is it down some. So let the truck cool off as the exhaust is right there by the fill plug port, I went ahead and pumped in a quart of ULV and then repeated the warming up of the trans and once again checked it and decided to catch the oil assuming it would flow out with a spotlessly clean measuring container and literally one quart ( ok so I am working with liters up here but whatever ! ) ran out and capped it at that volume I had put in as I think the trans temp was slightly higher than the first test. In any event it will be right there where it should be but what a pain, too full and excess runs out until its flow slows down but too little oil and a person is clueless unless putting more in and I certainly wasn't going to do it how I was equipped with the exhaust right there that I am squeezing in between with my bare hand to get my little sucker/filler hose into the port. But at least that satisfied me that I would not be driving around with low levels including the trans, a good starting point anyway vs wishing I had done it looking back from the future.

[Another JR]

11 minutes ago, Chuck FB said:

Now that you say that, I should have clarified from where I was calling the full mark and how far down the levels were from full, on the front and rear diffs and the transfer case. So from the considered "full" level as per the bottom of the threads of the fill ports is where I was referencing from. I know I have seen some specs in the past as to the lower acceptable range on the diffs as well as the full mark claiming to be at the threads on the diffs. Oddly I can not find any full level spec in the owners manual that has the limited amount of maintenance information, nor do they even say what the oil volumes of the diffs are or even what type of oil, "see your dealer" seems to be the theme there. However it does happen to state in the manual that if the transfer case level is found to be below the fill plug threads that the course of action is to fill it to the threads but they don't give a lower acceptable value which may mean they don't really have a lower level limit on it, just make sure its full. In topping up the diffs, the factory oil is 75W90 rear and they call for 75W85 front but of course 75W90 has been run for years in the front diffs, its all about getting that last little bit of fuel mileage. Anyway I wasn't too worried about the front since it wasn't going to take much volume and used from my five gallon pail of 75W90 I use in highway tractors and so on with the pump on it, same for the rear. Its the rear diff out of everything that concerned me as being well below any spec I have come across and yet it seems to be a theme and have seen mechanic youtubers that have bought an HD truck and they found the same thing with the oil being down 1 inch when they measured it.

 

It would be nice to have access to a shop manual, not that I would understand all the jargon but there would be a lot of invaluable information in it.

 

By the way the automatic trans, I had it up to temp and then pulled the check plug on the bottom and only the dribble from its stand pipe came out so there was no way of knowing where the level really is, is it there or is it down some. So let the truck cool off as the exhaust is right there by the fill plug port, I went ahead and pumped in a quart of ULV and then repeated the warming up of the trans and once again checked it and decided to catch the oil assuming it would flow out with a spotlessly clean measuring container and literally one quart ( ok so I am working with liters up here but whatever ! ) ran out and capped it at that volume I had put in as I think the trans temp was slightly higher than the first test. In any event it will be right there where it should be but what a pain, too full and excess runs out until its flow slows down but too little oil and a person is clueless unless putting more in and I certainly wasn't going to do it how I was equipped with the exhaust right there that I am squeezing in between with my bare hand to get my little sucker/filler hose into the port. But at least that satisfied me that I would not be driving around with low levels including the trans, a good starting point anyway vs wishing I had done it looking back from the future.

Thanks for clarifying about the levels, and for describing your check of the transmission. 

[Z45]

.....

Edited March 8, 2025 by Z45

[Grumpy Bear]

17 hours ago, BuckWallace said:

I guess my main concern is that if any damage was caused by the overfill and/or wrong oil, when is it going to become apparent? The only way to tell if anything has been damaged is to tear the engine open, which I definitely would not want them to do. I can just see something popping up five years down the road due to premature wear because of this, then I'm SoL since I'm out of warranty. 

 

The problem with over filling is windage. Foams the oil and then you loose oil pressure. But this happens when she's wound up a bit like when towing and you have her singing over 4K for awhile or you spin it to red line passing. There's an "The Oil Geek" dyno video for that.  Bearings are not fond of foam. 

 

That said if you weren't thrashing it.... 

[rjgvt]

I get 6 free oil changes at the dealer where I bought my truck, I've used 3 of them so far. I check my oil level frequently as some of the 6.6L motors burn oil. I check the oil level before going to the dealer for an oil change. Also check it the day after when the truck has sat overnight. Also check it before and after a long trip, ~850 to 900 miles. So far no issues at 16k miles. 

[Chuck FB]

1 hour ago, rjgvt said:

I get 6 free oil changes at the dealer where I bought my truck, I've used 3 of them so far. I check my oil level frequently as some of the 6.6L motors burn oil. I check the oil level before going to the dealer for an oil change. Also check it the day after when the truck has sat overnight. Also check it before and after a long trip, ~850 to 900 miles. So far no issues at 16k miles. 

I totally agree with how your keeping constant tabs on the level, its no different than running any type of construction or farm equipment, highway tractors etc, its part of a daily maintenance routine in those circles. I certainly hope my L8T will turn out to be a good one but I want to know sooner than later if there are any issues like using excessive oil. There was a reason years ago why service stations were full service, they ( if one would let them ) check the oil level and while not accurate as per having sat long enough, it was in theory someone at least checking it and adding if required. Its a good practice to get into and scan over the other fluids as well and add windshield washer fluid etc.

 

Grumpy Bear, yes I recall seeing that video from the oil geek and every engine design would have its point where the wind would affect it and in fact there is nothing to say that some engines could have such an issue due to design even with their intended oil level at high revs. There is some Russian youtube channel or a country in that area of the world and he's always doing some wacky test, he moulded a clear oil pan and bolted that to the engine, then started adding more and more oil in steps to see what would happen with aerating but also just how wild it would get by adding so much oil that the crank was partly submerged.

Edited March 8, 2025 by Chuck FB

[BuckWallace]

So today I figured I'd take a look at the PCV valve hose and found the little nipple it connects to, as well as the inside of the hose, has oil all over it. I understand the purpose is to allow vapor to escape the crankcase, but should there be this much?

Edited March 10, 2025 by BuckWallace

[the wanderer]

On 3/8/2025 at 9:18 AM, Grumpy Bear said:

 

The problem with over filling is windage. Foams the oil and then you loose oil pressure. But this happens when she's wound up a bit like when towing and you have her singing over 4K for awhile or you spin it to red line passing. There's an "The Oil Geek" dyno video for that.  Bearings are not fond of foam. 

 

That said if you weren't thrashing it.... 

 

HPL's oils don't foam, not even a tiny bit.

[BuckWallace]

Got the UOA analysis back today. Thankfully, it appears as if they at least put the correct oil in it. I'm just going to stop worrying about it since it doesn't appear anything adverse happened as a result—I'm just glad I'm done with the free dealer oil changes!

[Chuck FB]

Well that certainly is good news they didn't put the wrong oil in, just carelessness I assume in how much oil they poured in. What brand and flavour within the brand of oil did you put in when you changed it yourself ?. For curiosity sake if you wanted to do so, I'd be tempted to sample the oil again to send it out but not this oil change your on yet assuming its the same oil change you did when you discovered the extra volume, but the next oil change so that the oil the dealer used will have been pretty much flushed completely from the system. The viscosity being one aspect to recheck and if this is typical of the oil sheering down that far or if the oil at the dealership has a question mark, or if it happened that you had a few engine starts and it caused some of the issue with a bit of fuel contamination. Anyway glad to hear it was the correct oil at least.

[Jim71]

Just keep changing your own oil, and you will never wonder is this simple task was performed properly.

[BuckWallace]

1 hour ago, Chuck FB said:

Well that certainly is good news they didn't put the wrong oil in, just carelessness I assume in how much oil they poured in. What brand and flavour within the brand of oil did you put in when you changed it yourself ?. For curiosity sake if you wanted to do so, I'd be tempted to sample the oil again to send it out but not this oil change your on yet assuming its the same oil change you did when you discovered the extra volume, but the next oil change so that the oil the dealer used will have been pretty much flushed completely from the system. The viscosity being one aspect to recheck and if this is typical of the oil sheering down that far or if the oil at the dealership has a question mark, or if it happened that you had a few engine starts and it caused some of the issue with a bit of fuel contamination. Anyway glad to hear it was the correct oil at least.

Yeah, I was planning on sending in another sample after my next change or two. My sample was from the old rinsed-out lemonade jug (rather than as it was draining out of the oil pan as they recommend), so I wonder if some water left over in the jug settled on top and contaminated the sample and affected the viscosity.