Alright folks, I'm new round these parts but I want to assure you that I have a good head on my shoulders and will always do my best to share my ideas and opinions with any of you.
That said, I did a search and didn't find jack so I wanted to throw out something called "Engine Oil Analysis". Mods, if I missed it and a thread already exists, kindly merge. Thanks.
On to the skinny.
For those of you that don't know what engine oil analysis is, it is a range of tests you can run on your used motor oil that will assist you in determining signs of premature wear, leaks and other ongoing and sometimes otherwise undetectable problems. Coming from a military background and being well school in preventative vehicle maintenance, I am quite familiar with annual and/semi-annual oil analysis. FWIW, you can also have this type of test conducted on your transmission and transfer case.
I have had my JK Wrangler for just over a year and have managed to rack up 39,000 miles. Seeing as this is a daily driver, I have a long daily commute, wheel it regularly and really aint all that confident that my "lifetime drivetrain warranty" is worth the paper it's written on, I want to be sure I'm taking the best care of my Jeep as I possibly can. SO! I sent my 38k oil change off after 4200 miles on it and had it tested using a standard analysis.
The standard engine oil analysis consists of a spectral exam, viscosity check, insolubles check and flash point check.
A spectral exam checks the levels of wear metals, silicon, and additives present in the oil as well as the presence of coolant. This test can tell you if your bearings are wearing prematurely or if you have an internal leak (such as head gasket).
A viscosity check, of course, determines the grade of the oil. Viscosity can degrade as the oil wears. This test will tell you if you can extend out your change interval or maybe you need to change it more often than you are.
Insolubles quantifies the percentage of solids present in the oil indicating how well your engine is filtering both the oil and the air it ingests.
Flash Point determines the flash point of the oil. This is used to determine whether any contamination is present in the oil and is determined when the flash is lower than it should be.
Now this is all VERY good information to have as your engine begins to rack up the miles and if it is done on a regular basis, can help you diagnose engine problems LOOONG before they result in a critical breakdown.
There are assuredly innumerable laboratories out there that can do this for you and I certainly cannot recommend any single one of them, however I can tell you that I am currently using Blackstone Labs and am happy with their service and reporting procedures. I mailed off my sample on Friday last week (USPS) and today in my email I have a PDF of the results and they will be sending a hardcopy via snailmail.
On that note, this is what they had to say (synopsis, the actual values were listed in a table I won't include here)
"Based on data from this initial analysis of oil from your 3.8L, this engine appears to be in good shape. Universal averages show typical wear levels for this type of engine after about 5,000 miles on the oil. This oil was in use a little less than that and wear metals are very much in line with averages, some reading better than average. Insolubles, which are oxidized solids caused by heat, use, and blow-by, read low at 0.2%, showing good oil filtration and no combustion problems. No fuel, coolant, or water was noted. Try 6K miles on the next fill of oil."