I've been fretting over $7 a qt Mobil-1 since we tow heavy in southern heat or cheaping out with $3 a qt Motorcraft syn blend. I don't know if I would ever see the benefits of $7 Mobil-1 but, I used it in my '05 Hemi powered 2500HD and at 120k miles, it ran like day one. May have done as well with cheap oil but, I slept better knowing it was in there. If I have an oil related failure with Mobil-1 in the pan, at least I'll know it wasn't because I cheaped out on the oil. Makes no sense at all does it!

 

Use whatever says it meets or exceeds Fords specifications & makes you feel good & sleep well,

 

Just got back from my trip to Florida pulling my 30 ft 5th wheel with my 7.3. I drove over 4000 miles with no issues on the 5\40 syn rotella. This is the first time I have put in a synthetic oil and I have not noticed any real changes, no oil consumption, no better fuel mileage that I can notice. The ford shop also flushed my trans and put in syn oil in there and that didn't make any difference that I could tell but I sure did sleep better.

 

Thanxs for the replies on my rotella experiences, I will continue to use 5\40 syn because I believe it is a full syn oil at a great price and I know Rotella is a good oil.

 

Ah! I couldn't stand it any longer. I gave in to the hype and placebo affect and paid the $7 a qt for Mobil-1 5w-20. Maybe on one of those long uphill climbs this summer with the 5th wheel in tow I'll benefit from the extra protection. If nothing else, I'll sleep good with it in there.

 

Diesel Man, I've never personally seen any difference in mileage using synthetic. I started using it after an engine builder engineer that was involved in the development of the 5.7L Hemi engine suggested that if he were towing as much weight as we were at the time of 10,400 lbs, he would run Mobil-1 5w-30. Then the sludge problem with the 4.7L Durango lead to Mobil-1 for it for the cleaning since the wife drives short trips to work. So far no sludge problems with ours. But no change in mileage and certainly not in engine temps as I've seen claims of with synthetics. My thermostat still opens at 180*F or whatever it's designed to open at. I never used synthetic in the Diesels I owned. With the construction of the diesels and larger bearing surfaces and oil capacity, I never felt the need for more than Rotella or Valvoline Premium Blue. I bet most folks who switch to synthetics for mileage are also trying to achieve better mileage after the change with their driving style so when they see better mileage they attribute it to the synthetic oil. I believe it gives better mileage but I doubt it's enough to measure with normal driving. The engine probably doesn't know the difference but I do. Maybe I should pour some on some waffles!

 

IF synthetics could be scientifically proven to increase fuel mileage over friction modified dino, every car and truck maker in the United States would require it. CAFE regulations put much pressure on them to find efficiency anyplace they can without reducing safety, content or horsepower.

German carmakers specify special synthetics (not just any Mobil One, Syntec, etc.) in order to extend drain intervals, not for mileage. xW-20 is what Ford, Honda and more recently Toyota specify for CAFE, because it is thinner than xW-30 at operating temperature. That reduces hydrodynamic drag inside the engine. Base oil composition is not the issue. Any oil company can "rig" a test that favors its product, but CAFE is based on the repeatable, universal EPA test cycle.

Jim

 

There have been anecdotal claims made on both sides of this debate. Many claim increased MPGs. Many others claim no change at all.

I am reminded of one post by a Big 3 engineer a couple of years ago about a test they did on some "Super Fuel Saver" additive. In Round 1, they told the additive people that they were getting the real deal, and the non-additive people that they were getting the dummy liquid. Sure enough, the additive people reported increased MPGs and the dummy liquid people reported no MPG difference.

In Round 2, they gave the additive to a group of people and told them it was the dummy liquid. They gave the dummy liquid to another group of people and told them that it was the additive.

Sure enough, the group who thought that they got the additive (but really got the dummy liquid) reported increased MPGs. The group who thought that they got the dummy liquid (but really got the additive) reported no difference in MPGs.

I have a pharmaceutical industry background, where double and even triple blind studies are the norm. The placebo effect (sugar pill) is absolutely amazing and has been well-documented in many, many studies.

I have seen studies in which 50%-60% of the people in the group who actually got the drug had some improvement, but 30%-40% of the people who got the sugar pill also showed some improvement. One of the harder things to do in a drug trial is to show that your new drug is actually better than the sugar pill!

So when people say they made some change, like switching over to a full syn., and then tell me they saw a noticeable change, I am skeptical at best.

 

The irony of it is, I "know" it's placebo. But I shell out the $7 a qt anyhow. But that's pretty much how the human brain works. Most of the time with us hairless apes, it not what IS but, what we perceive it to be. TV and paper ads have gone crazy with it. Movies and shows, especially infomercials are full of it. Every four years we get a real big dose of it. $7 a qt and I know better...