What oil to use? T triple protection 15w-40 or T6 synthetic

[matt.ahern]

Okay i saw your post on the MoHo - Cummins 8.3 - you are using 15w-40 Shell Rotella T "triple protection" w/ Rislone Additive (6 gallons)

I was looking on Shell's site about the difference between synthetic T6 vs T it looks like the synthetic is just a bit better - not sure. its more expensive though

http://www.walmart.com/ip/Shell-Rote...om/ip/42299972 (3 gallons 55.00) is a great deal @ 2 would be $110.00 + tax.

comments pls

[matt.ahern]

also what rislone additive are you using ?

http://rislone.com/product/high-perf...oil-treatment/

http://rislone.com/our-products/?category=fuel-2

[Josh]

Another very good question. My basic thinking on oil for our awesome old Cummins engines involves a few different lines of reasoning.

First, although the synthetic looks like a good deal it is still almost double the price of the regular Rotella T which I wouldn't hesitate to pay if I thought it had some benefit for us. The main benefit of synthetic is longer life span from a mileage standpoint but not necessarily from actual age of the oil. Oil should be changed yearly on our rigs even if they are barely driven. Assuming you only put a few thousand miles a year like the average RV owner (my limit would be five thousand), then the Rotella T will serve you fine and the extra longevity of the synthetic is a waste. Some of what you are paying extra for is the technology that prevents damage to modern emissions control systems.

Second, based on my old school knowledge (possibly outdated and useless) many older engines develop leaks when switched to synthetics. The materials in old gaskets sometimes didn't seal properly when exposed to synthetic oils.

Third, old solid lifter motors need the Zinc lubrication to maintain a healthy valve train and it's good for turbo bearings and the Rotella T has a good high Zinc level but still not as much as the oils back in the day. It appears the T6 has similar good levels of Zinc but for much more dough. I add the Rislone to boost the Zinc (ZDDP).

Rislone 3x ZDDP Engine Treatment

Shell Rotella T6

Shell Rotella T Triple Protection

[matt.ahern]

http://www.ezoildrainvalve.com/ Price: $23.38

http://www.amazon.com/EZ-EZ-104-Oil-...3956313&sr=8-4

B-Series (3.3L, 3.9L & 5.9L), C-Series (8.3L), ISB, ISC, ISL engines

EZ-104