This is the first UOI for our 2001 Impala with the 3.4 L engine and 75,067 miles at the time of oil sample.
Oil analysis kit was NAPA "FIL 4077" for $14.35 + tax.
We purchased this vehicle with 30K miles on it 9 years ago, and ran Mobil drive clean 5000 5W30 with 3K OCI, until 13K miles ago.
Then I switched to GC, both to help stop some minor oil leaks and to go with longer oil changes.
Ran GC with new Purolator extra long oil filter PL24011 for 5K on the first fill of GC.
Then I ran this most recent fill of GC with new PL24011 for 8K miles over 24 months.
The oil analysis from NAPA calles TBN "Physical/Chemical Base Number (mgKOH/g)" and the report shows a value of 2.0
I know anything lower than 1 is no good, so I guess a value of 2 (even though I did not know this value at the time) was a good time to change it. I figured 2 years was about the maximum I wanted to run GC for, and with 8K on it that was certainly better than the 3K OCI I use to run, as far as getting my moneys worth out of an oil change.
Everything about the oil report is OK except that the viscosity came back as "Viscosity (cSt 100C) 14.2 Abnormal"
There was no make up oil for the 2 year 8K run of GC. The original viscosity of GC is supposed to be 12.1 (just below the maximum of 12.2 for a 30 weight).
Has anyone else seen GC having an increase in the viscosity with any similar amount of use?
I know 14.2 is about the middle of the 40 weight range, and certainly the engine was harmed running an oil that thick. But it is puzzling how an oil like GC can end up with a thicker viscosity than it probably had when new. I have read about oils shearing and having a reduction in viscosity. But I have no idea how an oil, especially an oil like GC, ends up with a thicker viscosity?
Any ideas of what could be going on causing the viscosity to show up as 14.2 after 2 years and 8K miles?
Here it the full report:
------------------------------------------------------------------------
Oil GC0W-30 Castrol European Formula
Miles in use 8,025
Miles on vehicle 75,067
Lab no. 41020697237 (the Ohio lab for for NAPA UOI)
Metals (ppm)
Iron (Fe) 110
Chromium (Cr) Lead (Pb) 196
Copper (Cu) 45
Tin (Sn) 7
Aluminum (Al) 21
Nickel (Ni) Silver (Ag) Titanium (Ti) Vanadium (V)
Contaminants (ppm)
Silicon (Si) 23
Sodium (Na) 67
Potassium (K) 5
Water (%) Coolant No
Additives (ppm)
Magnesium (Mg) 445
Calcium (Ca) 1626
Barium (Ba) Phosphorus (P) 781
Zinc (Z) 965
Molybdenum (Mo) 12
Boron (B)
Physical Tests
Viscosity (cSt 100C) 14.2 Abnormal
Physical/Chemical
Base Number (mgKOH/g) 2.0
-----------------------------------------------------------------------------------
Please feel free to make any comments regarding this report.
The 14.2 Aby-Normal viscosity for GC is puzzling to say the least.
At least it did not thin out.
Thanks in advance for any ideas of what is going on here.
Sincerely,
JimPghPa
PS: to the moderators, I wrote this report taking time to have all the numbers aligned in one column like shown in the post about how a report should look. But when I hit Preview Post something somewhere in the combination of all the software, deleted the extra spaces that made all this line up. I then tried using the tab key to get things to align, and still an no go on getting the numbers into columns. Sorry, but I did try.
Oil analysis kit was NAPA "FIL 4077" for $14.35 + tax.
We purchased this vehicle with 30K miles on it 9 years ago, and ran Mobil drive clean 5000 5W30 with 3K OCI, until 13K miles ago.
Then I switched to GC, both to help stop some minor oil leaks and to go with longer oil changes.
Ran GC with new Purolator extra long oil filter PL24011 for 5K on the first fill of GC.
Then I ran this most recent fill of GC with new PL24011 for 8K miles over 24 months.
The oil analysis from NAPA calles TBN "Physical/Chemical Base Number (mgKOH/g)" and the report shows a value of 2.0
I know anything lower than 1 is no good, so I guess a value of 2 (even though I did not know this value at the time) was a good time to change it. I figured 2 years was about the maximum I wanted to run GC for, and with 8K on it that was certainly better than the 3K OCI I use to run, as far as getting my moneys worth out of an oil change.
Everything about the oil report is OK except that the viscosity came back as "Viscosity (cSt 100C) 14.2 Abnormal"
There was no make up oil for the 2 year 8K run of GC. The original viscosity of GC is supposed to be 12.1 (just below the maximum of 12.2 for a 30 weight).
Has anyone else seen GC having an increase in the viscosity with any similar amount of use?
I know 14.2 is about the middle of the 40 weight range, and certainly the engine was harmed running an oil that thick. But it is puzzling how an oil like GC can end up with a thicker viscosity than it probably had when new. I have read about oils shearing and having a reduction in viscosity. But I have no idea how an oil, especially an oil like GC, ends up with a thicker viscosity?
Any ideas of what could be going on causing the viscosity to show up as 14.2 after 2 years and 8K miles?
Here it the full report:
------------------------------------------------------------------------
Oil GC0W-30 Castrol European Formula
Miles in use 8,025
Miles on vehicle 75,067
Lab no. 41020697237 (the Ohio lab for for NAPA UOI)
Metals (ppm)
Iron (Fe) 110
Chromium (Cr) Lead (Pb) 196
Copper (Cu) 45
Tin (Sn) 7
Aluminum (Al) 21
Nickel (Ni) Silver (Ag) Titanium (Ti) Vanadium (V)
Contaminants (ppm)
Silicon (Si) 23
Sodium (Na) 67
Potassium (K) 5
Water (%) Coolant No
Additives (ppm)
Magnesium (Mg) 445
Calcium (Ca) 1626
Barium (Ba) Phosphorus (P) 781
Zinc (Z) 965
Molybdenum (Mo) 12
Boron (B)
Physical Tests
Viscosity (cSt 100C) 14.2 Abnormal
Physical/Chemical
Base Number (mgKOH/g) 2.0
-----------------------------------------------------------------------------------
Please feel free to make any comments regarding this report.
The 14.2 Aby-Normal viscosity for GC is puzzling to say the least.
At least it did not thin out.
Thanks in advance for any ideas of what is going on here.
Sincerely,
JimPghPa
PS: to the moderators, I wrote this report taking time to have all the numbers aligned in one column like shown in the post about how a report should look. But when I hit Preview Post something somewhere in the combination of all the software, deleted the extra spaces that made all this line up. I then tried using the tab key to get things to align, and still an no go on getting the numbers into columns. Sorry, but I did try.