More oil talk

[BrianX128]

So at Walmart today I noticed for the first time a rotella 15w-40 synthetic t5. Usually I notice a t5 10w-30 synthetic and a t6 5w-40 synthetic. I had considered the 10w-30 synthetic for winter but after noticing this t5 15w-40 synthetic I'm very tempted to give that a try next oil change. The regular 15w-40 just is so thick on cold mornings and I've read many a thread on various subjects hearing so many good things for synthetic.

I also know he previous owner used the same rotella oil for the first 100k miles and I've kept doing the same for the 10k I've owned it. I don't imagine that there would be any real negatives since it's the same weight oil and brand name just synthetic... Truck doesn't burn much oil maybe a quart every 2000-2500 miles. That might increase with synthetic I suppose from what I've read. Thoughts or concerns? I don't really need it to be thinner or crank faster but if there are no negative drawbacks...

 

[pickupman]

I put in the Rotella T5 for my last oil change. It was the same price as the normal Rotella at the time, so I figured why not. It has worked fine for me. I do notice that they call it a "synthetic blend", so it may not be a full synthetic, thus the cheaper price.

 

[hce]

15w-40 synthetic kind of defeats the purpose for cold startup. The 15 is how a straight 15 weight oil would flow when cold. The 40 reflects operating temperature and is how a straight 40 weight would flow at operating temperature (212 F). At operating temperature a 0w-40, 5w-40 and 15w-40 will flow the same. At the rated cold temp(Have never found what this temp is) a synthetic and conventional 15w-40 will flow the same. If you want thinner oil at startups look for a 0w-40 or 5w-40, they are only thinner when cold, when all oils are thicker then the engine requirements.