Here is my first UOA on this truck, ran the HPL out to 10,000 miles. This is their CK-4 5W-30. The truck has 200,000 miles as of this oil change. Not sure I would go any further on this oil? I changed the filter halfway and probably added a total of 2 quarts make-up oil.
HPL 5W-30 CK-4 10,000 miles; 2002 GMC 2500 HD 6.0
- Thread starter Oscar11
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What did you find in the filter? If the TBN really is 3.45 (starts at > 13), then this oil has cleaned a lot of stuff from the engine and it may be a good time to change the oil.
Iron is pretty good for 200k, on engine, but can tell the Al Cu & Pb are elevated slightly. That is expected for a working truck engine at that point. fuel not too bad & viscosity still within a 30 grade. Great run! Si is creeping higher but you could probably get another 2,500 miles out of it based on that alone. So, run it to 12,500 miles if you want. 
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There is a ton to be learned from what is caught in the filter...
I will do that this time then. Would you suggest changing it halfway through again?
when were the 2 quarts make up oil added? if the engine was due another quart of makeup oil, that would boost TBN again and you likely could go a bit further. But if the last quart was added recently, you really don't want to go longer. But it seems like you added the 2 quarts when you changed the filter, so no actual consumption of oil?
Is this the first run of HPL?
Is this the first run of HPL?
Yes, if lots of carbon is being cleaned from the engine, it will load the filter fairly quickly.
I added a little less than a quart when the filter was changed, then periodically added 1/2 a quart at a time. I probably added closer to 3 quarts over the 10,000 miles because it does use a little oil, but I really didn't keep track like I should have. It was probably a 1/2 quart low right when I changed it, it's been a little while since I had added some. This was the first time I have run HPL in it. Previous 2 oil changes were Pennzoil synthetic (can't remember which one) at 5,000 oci
It's fine. HPL uses ester so it starts with a higher oxidation number.
the oxidation number notes how much oxygen is in the oil, this could come from old oil that reacted with oxygen or from esters which contain oxygen from the start. The oxygen makes the oil attracted to metal, so in the case of esters it helps keep metal coated with oil, or in case of oxygenated oil, it causes deposits like varnish.
The number is only of use if you know what the oil started with. Most oils will start with less than 15, but ester containing oils can be as high as 90 out of the bottle.
In that case I would change the oil filter at 5k (and check it for dirt/carbon) and then decide to keep changing every 5k, but I'd run the oil 15k, and keep the oil level topped up.
If the oil filter doesn't need changing every 5k there's less fresh oil added and I'd stick with 10k max.
What is the oil capacity for this engine?
Now you’re saying you “probably added 3 quarts over the course of the 10,000 miles.” You also said “it’s been a little while since I added some.”
Define “little while,” mileage wise.
Depending upon the oil sump capacity those three quarts could definitely slew the numbers on this UOA.
Now you’re saying you “probably added 3 quarts over the course of the 10,000 miles.” You also said “it’s been a little while since I added some.”
Define “little while,” mileage wise.
Depending upon the oil sump capacity those three quarts could definitely slew the numbers on this UOA.
The capacity is 6 quarts. The engine probably uses a 1/2 quart every 1500 miles or so, just estimating. The filter change at 5000 miles didn't require a whole quart, just estimating a 3 quart total on make-up oil through the whole oci. It was down 1/2 quart when I changed it, so I hadn't added any in about 1500 miles or so. All of the numbers are just guesses, as I didn't track it or write it down.
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