What did you do to your NBS GMT800 Tahoe/Yukon Today?

[Rocket Man]

Not sure why it says 14 miles on it for 2017. I believe it had about 140k on it or so. Maybe they forgot a few zeros on there, lol. But yes, my last sample was indeed much worse. I just chalked it up to going SO long on the oil, because I went over 10k miles on it. The next one I only went about 5k, but I forgot to do a sample. Now I'm at 148k and just changed it and sent in another sample. It makes sense that all the wear metals are down, but there's still what they call critical levels of coolant in the oil. The ONLY visual sign of coolant I have EVER seen in my oil was moisture on the bottom of my oil fill cap. And I was told that is normal with my driving style, I very rarely drive more than 4-5 miles at a time, then the truck sits for at least 6-8 hours.

Whew, Im glad those wear metal numbers are down, that looked real bad last time and that note was scary. I’d do another test at maybe 1500 miles just to see what’s happening more short term.

 

[ScottyBoy]

Your wear numbers have certainly improved. Says a lot for a shorter OCI, imo.

Your sodium and potassium are REALLY high. After ~6k miles, mine were 8 and 2, respectively. You have coolant in there somehow. Your intervals are very long, so it's tough to guess how bad it is. A little leak adds up over such a long OCI.

I'm planning on doing another oil analysis at 3k miles this time.
Yes, I know I am losing coolant but I don't see any external leaks. I probably have to add almost a quart about every 10 months or so. A mechanic told me that was within the "normal" range but obviously it's getting into my oil somehow. I'm thinking about getting one of those cheap borescope cameras that attach to your phone. And inspect each cylinder with that and go from there. I don't know what else to do.

 

[ScottyBoy]

Whew, Im glad those wear metal numbers are down, that looked real bad last time and that note was scary. I’d do another test at maybe 1500 miles just to see what’s happening more short term.

Also, just before that oil change in 2017 with the very high wear metals, I did an engine flush. So I don't know if that loosened up any old crud and that's another reason why the numbers were so high. I flushed it, dropped the pan and replaced the oil pick up tube and screen. I had to replace a leaking oil pan gasket anyways, so I decided to flush it and get out any old sludge. And there was indeed some sludge in the oil pan. I COMPLETELY cleaned the oil pan before installing the new gasket though.

 

[HiHoeSilver]

Also, just before that oil change in 2017 with the very high wear metals, I did an engine flush. So I don't know if that loosened up any old crud and that's another reason why the numbers were so high. I flushed it, dropped the pan and replaced the oil pick up tube and screen. I had to replace a leaking oil pan gasket anyways, so I decided to flush it and get out any old sludge. And there was indeed some sludge in the oil pan. I COMPLETELY cleaned the oil pan before installing the new gasket though.

The flush would definitely raise those numbers.

 

[Rocket Man]

Also, just before that oil change in 2017 with the very high wear metals, I did an engine flush. So I don't know if that loosened up any old crud and that's another reason why the numbers were so high. I flushed it, dropped the pan and replaced the oil pick up tube and screen. I had to replace a leaking oil pan gasket anyways, so I decided to flush it and get out any old sludge. And there was indeed some sludge in the oil pan. I COMPLETELY cleaned the oil pan before installing the new gasket though.

Yeah I wouldn’t have done an oil analysis right after a flush. Their tests are pretty sensitive. I just did an analysis on my 08 Silverado that has 60k miles on it. I had no previous record of oil changes so I had no idea how long it had been, plus I realized after they sent the results back that I had drained the oil into the same pan that had been used to drain my trans on the Beast after I had grenaded it. I’m pretty sure the oil mixed in with whatever stuff that was deposited in that pan from the trans because the report pretty much said the engine on the Silverado was about done lol. That’s when I remembered what I had done when I got the sample. Next time it comes right out of the drain and into the sample container.

 

[HiHoeSilver]

Yeah I wouldn’t have done an oil analysis right after a flush. Their tests are pretty sensitive. I just did an analysis on my 08 Silverado that has 60k miles on it. I had no previous record of oil changes so I had no idea how long it had been, plus I realized after they sent the results back that I had drained the oil into the same pan that had been used to drain my trans on the Beast after I had grenaded it. I’m pretty sure the oil mixed in with whatever stuff that was deposited in that pan from the trans because the report pretty much said the engine on the Silverado was about done lol. That’s when I remembered what I had done when I got the sample. Next time it comes right out of the drain and into the sample container.

You want to make sure it's warm, and you get the sample from the "middle" of the drain. I usually open the plug, then about 3 seconds in, fill the sample jar (straight from the drain), pour it mostly out, count to about 5, and then fill it again. Call me crazy. Lol.


Here's my latest sheet. The time before last was when it was -30 here and I waited until almost 6k to change it. Didn't add any, but should have because I found it low. Too low. I have to think that's why the numbers were so bad. Did everything the same for collection. Had me worried for a minute. Newest sample in the mail now.

 

[Rocket Man]

You want to make sure it's warm, and you get the sample from the "middle" of the drain. I usually open the plug, then about 3 seconds in, fill the sample jar (straight from the drain), pour it mostly out, count to about 5, and then fill it again. Call me crazy. Lol.


Here's my latest sheet. The time before last was when it was -30 here and I waited until almost 6k to change it. Didn't add any, but should have because I found it low. Too low. I have to think that's why the numbers were so bad. Did everything the same for collection. Had me worried for a minute. Newest sample in the mail now.

View attachment 232615

Yeah I knew how to take a sample, just forgot to do it while it was draining so I poured it out of the drain pan. Not smart lol.

 

[HiHoeSilver]

Yeah I knew how to take a sample, just forgot to do it while it was draining so I poured it out of the drain pan. Not smart lol.

Lol. If I did that, his note would say "We found high levels of maple leaves and spider webs in your sample...."

 

[Rocket Man]

Lol. If I did that, his note would say "We found high levels of maple leaves and spider webs in your sample...."

Or more likely the chemicals that make up maple leaves and spider webs. I’m pretty sure my sample confused them with clutch material and trans fluid and who knows what else was in there from a grenading 4l60.

 

[Tonyrodz]

Head bolts came in.