My understanding (I could be wrong) is they cut back on the zinc in Rotella a few years back because of cat problems.

I do think weight is more important than dino vs. syn. It's critical to match ambient temp to oil weight. I bought M110w-30 because it was easy to find, and because I thought the M1 20w-50 was probly a bit thick for my Arkansan winter where temps will hover around the 30-40s. I'll probly swap it for Amsoil 10w-40 in the spring, and then run that year round.

I personally plan to send a oil sample for analysis when I think it's almost exhausted. If it's time, I'll change it. If not, I'll wait a bit and send in another sample. After a coupla oil changes I should be able to nail down an oil change interval appropriate to my vehicle/oil/driving habits.

I just go to Wallmart and by the dino Rotella for $12.95 a gallon, get the Purolator oil filters at Amazon for $3.66 and change it every 3k miles.

Worth it using Rotella in synthetic? Or don't waste money and just use dino version?

This^^^

It's not the difficult; use a good oil and filter and change regularly. Do the above with a full syn at 5k. Either way, fresh oil and a filter that traps and holds grime and you'll be good.

But then again, if it was that simple, we wouldn't have multiple threads with multiple pages of replies

My .02:

Synthetic and change at 5k miles
Dino and change at 3k miles

The cost difference is not that great to run syn; one less 12-pack per oil change interval is all.

First, see my earlier post out the advantages of synthetic oil.

Second, a 5w-XX oil is very thin when cold. This is always good - it means the oil circulates quickly througout the engine during the period of greatest engine wear (start up).

As that 5w-XX oil heats up, it thickens to the XX value. So a 5w-40 and a 15w-40 have the same thickness at running temps. The only difference between them is the 15w is thicker on start, which isn't a good thing. If it gets well below 0 deg F where you live, 15w is a bad idea because it thickens so much when very cold.

Really, the only reason to run 15w-40 is it's usually a dino oil and cheaper. 5w-40 synthetic will do everything the 15w-40 will do but better, and will last longer also. I'd feel very comfortable running Rotella 5w-40 out to 8000 miles if it still looked good. I've read reports of people running it out to 12k-13k miles before it needed to be replaced.

So what you have learned after 36 posts is this board is kind of like congress they cant agree on crap. if you want to run synthetic run 5w-40. if you want run Dino run Rotella 15w-40 adjust for temperture; either way run a good filter and change it often.

I have been using Rotella T6 5w40 and a Purolater L30001 filter. It's easy to get and not that expensive (Wal-Mart). So far so good.

New England.. your weather mimics what I see down here.

Get the Rotella T6 5w40 for all the reasons already mentioned. Aside from the superior zinc content, the ability to encapsulate particulate until it gets filtered is huge.

Changing your oil every 3,000 miles, even with dollar store brand motor oil is to often and a waste of money.
Changing your full syn motor oil every 5,000 miles is also a waste of money.
I use Rotella, change it every 5,000 miles and dont worry about it, its just a truck.