Shell Rotella T 15W/40

[TuxedoPk]

I was prepared to change my engine oil on the 468 today to Mobile 1 synthetic. Picked up 16 quarts, drove to the marina and was advised that since the engine is older and has always been run with non-synthetic oil that I should be using Shell Rotella T 15W/40.

I know that 'oil' is a fighting topic here, but does this make sense? What would be the recommended number of hours of run time between oil changes?

Also, what oil should I be using on the Caselle V-Drive and how frequently should I change it?

[txtaz]

Scott, You have a drum of Amsoil 20-50? Can we work something out to get several gallons? Even though synthetics are more expensive, I think it's worth it in the long run. After I finish up the case of Mercury oil I have left, I'm going synthetics on everything.
Thanks,
Wes

[TuxedoPk]

Rotella was changed a couple years ago, it is not the oil it used to be. Currently Shell is doing lad analysis on the Kendal Oil I am using in my truck.....
A straight 40 WT IMO is fine for your engine. Boats put more stress on the oil, and as such need more frequent changes, so IMO a synthetic is a waste.. and yes, I am an AMSOIL dealer. drum of 20 - 50 in stock for the boats, never opened it...

If you don't like the current Rotella T, whose 15/40 WT would you use? What is a realistic period of time between changes?

Also, what oil should I be using on the Caselle V-Drive and how frequently should I change it?

[David Ochs]

[QUOTE=TuxedoPk]If you don't like the current Rotella T, whose 15/40 WT would you use?



There is "Delo" 15-40. I use it in my power-stroke truck. i buy it at either Costco or Wally's.

[Cuda]

I have Rotella in my F20. Since I put it in, I haven't put enough hours on the boat to make a determination. Somebody told me a reason not to use diesel oil in a boat, but I don't remember what it was, and I remember not putting much stock in it. Diesel exceeded automotive oil in all aspects in a study I read one time. I can't see a reason not to use it. If I ever get the boat back on the water, I'll give it a real test.

[smokediver]

just curious but why does merc. use 25w 40 ?

[mikev]

just curious but why does merc. use 25w 40 ?

probably same reason gm tells you to change oil every 7500 instead of 3k recomended by oil manufacurers because the want to sell you another motor sooner? just a guess though. or else they figure most people who buy boats are idiots and dont let the engine and oil warm up well before they really get on it.

[Gary S.]

I was a diesel mechanic for 9 years and I will say that I don't run 15-40 oil in any gas engine, diesel oil is exactly that, for diesels. without going into a 10 page response and keeping this sorta short,,,, the 15 weight is because the tolerances in a diesel are so much tighter than gas,,,a brand new gas engine is worn out and sloppy to diesel standards the 40 weight helps with the huge amounts of stress and high heat in the diesel. Also there are a lot of attitives and detergents in it for all the soot that used to go up the stacks,,, it's now going in the oil. Rotella is a great diesel engine oil BUT, you won't find anything except straight weight Pennzoil in my King Cobra.