Gitpik

My truck now has 20,000 on it and someone advised me to switch to synthetic oil. What's the membership's view on this ? Does one still chage oil at the same milage interval and if I do switch what's the best choice of oil for my 5.9 Cummings.. Thanks for all opinions.

3500lly

It's be fine to switch but I'd recommend installing an oil bypass such as FS-2500 or an amsoil system when you do it because sythetic oil isnt cheap and an oil bypass will greatly lengthen your intervals plus add filtration to a smaller particle size

wcbcruzer

You can switch. It would be quite a waste of money if you change it often though... Get a bypass if you do it.

lgp9999

Change to synthetic and change it at the oil manufacturer's recommendation. With Amsoil they recommend around 25K miles, depending on which series you buy.

Synthetic oil does not break down like petroleum does. A *good* synthetic's only weak point is its filtration. You really don't even HAVE to change the oil (once again, if you're running GOOD synthetic), but if you choose not to, make absolute sure that you're doing semi-regular oil analysis's (is that a word? LOL!). I've never had the ***** not to change my oil, I usually just do it by Amsoil's recommendation, as it's far enough apart for me that it's not a PITA.

There was once a trucker who was using Amsoil products and went over 300K without an oil change (he did regularly scheduled filter changes, obviously). The internal engine parts were then inspected, and found to be in prestine condition.

Gitpik

I have sent the FS2500 dealer an e-mail enquiring if they have a Canadian dealer. If not we also have a place down in Reno so will have it shipped there. Thanks a million guys. The FS2500 video was really impressive and sold me on the spot.

supr

Syn Oil only offers adnavtages if your truck gets overly hot, or in extrene cold at start-up. Cummins makes no exception to their oil change interval recommendationd bases on syn. If you want to keep your warranty, run whatever meets the Cummins spec. Their new Valovoline premium blue classic (a DINO lube recommended by Cummins) is an excellent lube, CI-4.
The NAPA CI-4(if available) is also made by Ashland Oil and is also a very high quality. Save your money and change your oil by the book.
It is your warranty.

Dieseljunkie

Go with a synthetic. I go about 25k between my oil changes with no bypass filter, just using the stock replacement Amsoil EAO series oil filter and Amsoil's 15w40 HD diesel and Marine motor oil. Works great, and I could go longer if I wanted to, but I change it for my peice of mind. If you would like to see some oil analysis results, I plan on posting up my results every 3 months or 5k miles, whichever comes first, here:

http://www.dieselbombers.com/showthread.php?t=4726a
Scott