Mhingram first of all, you want to make sure you are using a diesel specific synthetic oil, preferably with an API rating of CI-4. If you check your manual, most likely it has as specification requirement. My e300 requires CH-4, which CI-4 supercedes. Most MB dealers will not have this, so you'll have to make sure you get it. The dealer will tell you he has the right oil, and then will just dump in gasoline spec Mobil 1. Diesel specific oil has a different additive chemistry, designed to suspend soot and neutralize the acids of diesel combustion. Use the right tool for the job.
Secondly, high pressure common rail injection is extremely clean and complete burning, which typically lends to longer oil drain intervals. If you use gasser mobil 1, I definitely think 13,000 miles is pushing it. If you were to use mobil Delvac 1 , you could most likely easily do 15k miles on a change. These engines are nothing like the dirty old IDI mb diesels of the past. Even my '99 E300, at 7500 miles into the d1, oil analysis shows the oil is barely worn. Next time I'm going 10k. Oil analysis tests are about $15, not $30 by the way, and that's including a TBN test.. I would suggest running the oil out like I have to 7500, and doing a test, then 10k, then 13k or 15k, and see how the oil is doing. At 422/gal, you don't want to dump this stuff when it's still perfectly good ya know?
Some common high quality diesel synthetics(PAO/Ester synthetic base) are:
Mobil Delvac 1 5w40 (not to be confused with dino Delvac 1300 super)
Amsoil 15w40 Heavy Duty Diesel Oil
Amsoil Series 3000 5w30 HDD Oil
Redline 15w40 Diesel Oil
Some slightly less pure 'synthetics' (these have a group 3 petroleum base)for diesels are:
Shell Rotella T synthetic 5w40
Valvoline Premium Blue Extreme 5w40
Petro Canada Duron 5w40 (best of the bunch)
Tommy9298, depending on what type of oil you're using, oil analysis could give you tangible proof that you are throwing your money in the garbage can and doing the environment a disservice by dumping your oil every 3k miles. Most likely even though you are doing all city driving, and if you're using synthetic, you can easily and safely extend to 5k.
Aus - we have low sulfur diesel here in the states - less than 500 ppm.
Hope this helps guys
