805cherokee
NAXJA Forum User
- Location
- California
Hey guys I am new on here and I just changed the oil and oil pan gasket. I want to know if anyone has or suggests adding bestline oil additive to an xj with 205054 miles?
Agreed. (Good) modern engine oils have a lot of chemical engineering know-how put into them and shouldn't require the use of any special additives. In fact, adding additives to them can actually mess up the formulation of the oil, rather than help it. That being said, changing a high-mileage 4.0 that has seen nothing but cheap conventional it's whole life to a synthetic oil can cause oil leaks since the additional detergents in the synthetic oil can knock loose crud around the seals that was keeping them from leaking in the first place. For what it's worth, I run Mobil 1 High Mileage 10W-30 synthetic in mine with a K&N oil filter. I will also say that I don't buy into the 7,500 mile "normal use" oil change interval in the owner's manual. Thus, I usually split the difference between that and the 3,000 mile "severe use" interval and change my oil every 5,000 to 5,500 miles.
Don't run K&N - avoid them like the plague. They let too much fine dirt get through. The DSPO ran a K&N and my first oil analysis was scary with the level of silica. I switched to an AEM Dry Flow (same as we run on the desert racer) and haven't had a bad analysis since. I run Mobil 1 High Mileage 10-40 with a Motorcraft FL-1A filter. Also with the analysis, I have found that 7500 miles is just fine, and the lab is saying that I could probably extend to 10K miles based on the test results. I also don't buy into the "if you switch to synthetic it will leak" hype. It had 180K miles when I bought it, and now has 216K and I had nothing start leaking when I switched to synthetic.