SUNRG
Top Post Dawg
- Joined
- Oct 19, 2003
- Location
- Roanoke, VA
- TDI
- None currently. Previously owned 04 Golf TDI & 05 Passat GLS Wagon TDI
Many moons ago, TwoSlick posted SAE study info (IRCC) that indicated that the initial wear (engine wear immediately after an oil change) is higher than the subsequent engine wear (wear that occurs once the new oil's anti-wear additives have established themselves). Since then, I've done extensive UOA testing in my TDI to begin to see if this "higher initial wear" theory is applicable to PD TDIs.
My results so far indicate that initial wear (0-2000miles) is higher than the engine wear in subsequent oil sampling intervals (2000-4000, 4000-6000, 4000-8000 (missed 6000mile OSI in second testing)).
Note: To exclude both inherited Fe wear metal particles and naturally occurring Fe in the oil (many oil VOAs will come back with Fe of 1 or 2) I did preliminary oil sampling at 94 miles on the first OCI and 228 miles on the second OCI - and only Fe wear after these respective data points was considered.
(note: this sequence ended prematurely when a rock took out my oil pan)
Test Sequence#2: OSI / Fe Wear Rate
(note: this oil is still in my Golf PD-TDI and will be tested again at 10,000 miles)
Based on these and other UOA results in this vehicle, the 50,000 mile oil change will likely be my last 10,000 OCI, since this data suggests that at least through 8,000 miles, draining good oil and replacing it with new oil results in more wear than just leaving the good oil in.
Important Note: Wear trends in your vehicle may be very different. I recommend using used oil analysis to determine the optimal OCI length for your TDI.
My results so far indicate that initial wear (0-2000miles) is higher than the engine wear in subsequent oil sampling intervals (2000-4000, 4000-6000, 4000-8000 (missed 6000mile OSI in second testing)).
Note: To exclude both inherited Fe wear metal particles and naturally occurring Fe in the oil (many oil VOAs will come back with Fe of 1 or 2) I did preliminary oil sampling at 94 miles on the first OCI and 228 miles on the second OCI - and only Fe wear after these respective data points was considered.
Oil: Elf Evolution CRV 0w-30 506.01
Oil Filter: OEM MANN
Fuel: B33 (33% ASTM Virgin Soy BioDiesel - 66% common diesel from a variety of stations)
Fuel Filter(s): MANN In-Line Pre-Filter, Stanadyne FM100 5-micron and 2-micron elements
Air Filter: OEM Type A (includes pre-filtration media)
Test Sequence#1: OSI / Fe Wear Rate Oil Filter: OEM MANN
Fuel: B33 (33% ASTM Virgin Soy BioDiesel - 66% common diesel from a variety of stations)
Fuel Filter(s): MANN In-Line Pre-Filter, Stanadyne FM100 5-micron and 2-micron elements
Air Filter: OEM Type A (includes pre-filtration media)
(note: this sequence ended prematurely when a rock took out my oil pan)
- mile 94 to mile 2011 / 3.12 (higher initial)
- mile 2011 to mile 4007 / 1.00 (lower subsequent)
- mile 4007 to mile 6008 / 2.50 (lower subsequent)
Test Sequence#2: OSI / Fe Wear Rate
(note: this oil is still in my Golf PD-TDI and will be tested again at 10,000 miles)
- mile 228 to mile 2016 / 2.79 (higher initial)
- mile 2016 to mile 4319 / 0.00 (lower subsequent)
- missed mile 6000 sampling
- mile 4319 to mile 8108 / 1.84 (lower subsequent)
Based on these and other UOA results in this vehicle, the 50,000 mile oil change will likely be my last 10,000 OCI, since this data suggests that at least through 8,000 miles, draining good oil and replacing it with new oil results in more wear than just leaving the good oil in.
Important Note: Wear trends in your vehicle may be very different. I recommend using used oil analysis to determine the optimal OCI length for your TDI.