Most of the knowledgable people on this site will encourage you to get the engine oil analysis done before you buy. However, I didn't do that late last summer before I bought mine and so far I'm happy with the unit, granted I've only put a few thousand miles on it since then. I had the oil changed and other service work done by a Frieghtliner/Cat dealer when I got home with it (it was located about 850 miles from me). Time will tell how it holds up. The current owner may have a recent analysis for you to look at. I'm sure others will post better and more relevent info before too long.