I have owned my 1995 6.5 Diesel K2500 Suburban since new. It has 137,000 miles. I religiously changed oil every 3,000 miles for the past 22 years with Rotella 15W40. One oil change ago I tried the new T6 5W40 synthetic for better cold starts. The truck only gets about 6,000 miles a year. Only mechanical issue in its history was a blown headgasket at 121,000 miles, which occurred four years ago. (A common 6.5 diesel problem) It was caught immediately and shut off before the oil was contaminated.
The oil anaylsis report came back indicating I had over 17 times the lead amount (158 PPM versus 9), and 3 times the tin (9 PPM versus 2) and almost twice the iron (80 PPM versus 43).
Blackstone Labs opinion is that there is a serious problem brewing and were surprised that the engine is still running. It runs beautifully, with good oil pressure (55 PSI) and no knocks or other noises.
I use Optilube XPD fuel lubricant additive and regular diesel fuel.
Could it be that the change to the new synthetic 5W40 is somehow flushing out contaminants that were dormant in the engine all these years? Or is there a real problem brewing?
Just to be sure I sent them a second sample a week later from the same crankcase oil thinking maybe I contaminated it somehow by scooping the sample out of the drain bowl. But even the new sample caught mid stream was still bad: it had a similar result though the bad stuff was down by about 20% due to the addition of a new quart of oil (106 PPM lead, 6 PPM tin, and 63 PPM iron). At that point I changed all the oil to a new fill of syn 5W40 Rotella T6.
Any suggestions? I have been pricing out new 6.5 long blocks just in case...
The oil anaylsis report came back indicating I had over 17 times the lead amount (158 PPM versus 9), and 3 times the tin (9 PPM versus 2) and almost twice the iron (80 PPM versus 43).
Blackstone Labs opinion is that there is a serious problem brewing and were surprised that the engine is still running. It runs beautifully, with good oil pressure (55 PSI) and no knocks or other noises.
I use Optilube XPD fuel lubricant additive and regular diesel fuel.
Could it be that the change to the new synthetic 5W40 is somehow flushing out contaminants that were dormant in the engine all these years? Or is there a real problem brewing?
Just to be sure I sent them a second sample a week later from the same crankcase oil thinking maybe I contaminated it somehow by scooping the sample out of the drain bowl. But even the new sample caught mid stream was still bad: it had a similar result though the bad stuff was down by about 20% due to the addition of a new quart of oil (106 PPM lead, 6 PPM tin, and 63 PPM iron). At that point I changed all the oil to a new fill of syn 5W40 Rotella T6.
Any suggestions? I have been pricing out new 6.5 long blocks just in case...
Last edited by a moderator: